VIBRONIC MEASURING SYSTEM

Description

[0001] The invention relates to a vibronic measuring system formed by a vibration-type measuring transducer and electrically connected measuring system electronics, in particular a Coriolis mass flow meter or Coriolis mass flow / density meter, for measuring and / or monitoring at least one measured variable of a flowing medium, in particular a gas, a liquid, or a dispersion. The measured variable can be, for example, a time-varying flow parameter, such as a mass flow, a volume flow, or a flow velocity, and / or a time-varying material parameter, such as a density and / or viscosity, of the respective medium. Such measuring systems—typically designed as an in-line measuring device with a compact design—have been known for a long time and have proven themselves in industrial applications.not least in the field of control and monitoring of automated process engineering processes or process plants or in the area of transfer points of goods transport that may also be subject to legal metrology. Examples of vibronic measuring systems of the type in question are, for example, in EP-A 317 340, EP-A 816 807, JP-A 8-136311, JP-A 9-015015, US-A 2005 / 0125167, US-A 2006 / 0000293, US-A 2006 / 0112774, US-A 2006 / 0266129, US-A 2007 / 0062308, US-A 2007 / 0113678, US-A 2007 / 0119264, US-A 2007 / 0119265, US-A 2007 / 0151370, US-A 2007 / 0151371, US-A 2007 / 0186685, US-A 2008 / 0034893, US-A 2008 / 0041168, US-A 2008 / 0141789, US-A 2010 / 0011882, US-A 2010 / 0050783, US-A 2010 / 0101333, US-A 2010 / 0139417, US-A 2010 / 0236338, US-A 2010 / 0242623, US-A 2010 / 0242624, US-A 2010 / 0251830, US-A 2011 / 0167907, US-A 2012 / 0123705, US-A 2014 / 0352454, US-A 2016 / 0033314, US-A 2016 / 0349091,US-A 2016 / 0123836, US-A 2016 / 0138997, US-A 2017 / 0030870, US-A 2017 / 0356777, US-A 2020 / 0132529, US-A 46 80 974, US-A 47 38 144, US-A 47 68 384, US-A 47 77 833, US-A 47 93 191, US-A 48 01 897, US-A 48 23 614, US-A 48 31 885, US-A 48 79 911, US-A 50 09 109, the US-A 50 24 104, US-A 50 50 439, US-A 52 91 792, US-A 53 59 881, US-A 53 98 554, US-A 54 76 013, US-A 55 31 126, US-A 56 02 345, US-A 56 91 485, US-A 57 28 952, US-A 57 34 112, US-A 57 96 010, US-A 57 96 011, US-A 57 96 012, US-A 58 04 741, US-A 58 31 178, US-A 58 61 561, US-A 58 69 770, US-A 59 26 096, US-A 59 45 609, US-A 59 79 246, US-A 60 47 457, US-A 60 73 495, US-A 60 92 429, US-A 63 11 136, US-A 2010 / 0011882, US-A 2010 / 0139416, US-B 62 23 605, US-B 63 11 136, US-B 63 30 832, US-B 63 97 685, US-B 65 13 393, US-B 65 57 422, US-B 66 51 513,the US-B 66 66 098, the US-B 66 91 583, the US-B 68 40 109, the US-B 68 68 740, the US-B 68 83 387, the US-B 70 17 424, the US-B 70 40 179, the US-B 70 73 396, the US-B 70 77 014, the US-B 70 80 564, the US-B 71 34 348, the US-B 72 99 699, the US-B 73 05 892, the US-B 73 60 451, the US-B 73 92 709, the US-B 74 06 878, the US-B 75 62 586, WO-A 00 / 14485, WO-A 01 / 02816, WO-A 03 / 021205, WO-A 2004 / 072588, WO-A 2005 / 040734, WO-A 2005 / 050145, WO-A 2006 / 036139, WO-A 2007 / 097760, WO-A 2008 / 013545, WO-A 2008 / 077574, WO-A 2009 / 136943, WO-A 2011 / 019345, WO-A 2013 / 002759, WO-A 2013 / 009307, WO-A 2017 / 019016, WO-A 2017 / 069749, WO-A 2019 / 017891, WO-A 2019 / 081169, WO-A 2019 / 081170, WO-A 87 / 06691, WO-A 93 / 01472, WO-A 95 / 16897, WO-A 95 / 29386, WO-A 96 / 05484, WO-A 96 / 08697, WO-A 97 / 26508, WO-A 99 / 39164, WO-A 99 / 40394,WO-A 99 / 44018 or the applicant's own unpublished patent applications DE102019124709.8 and PCT / EP2019 / 082044 and have been manufactured by the applicant itself for a long time and are sold as Coriolis mass flowmeters or as Coriolis mass flow / density meters, for example under the trade name ", PROMASS G 100", " PROMASS O 100", " PROMASS E 200", " PROMASS F 300", "PROMASS X 500", " CNGmass", " LPG mass" or " Dosimass " (https: / / www.endress.com / de / search?filter.text=promass).

[0002] Each of the transducers of the measuring systems shown therein comprises at least one pipe arrangement for guiding the flowing medium, an excitation arrangement for converting electrical power into mechanical power useful for exciting and maintaining forced mechanical vibrations of the pipe arrangement, and a sensor arrangement for detecting mechanical vibrations of the pipe arrangement and for providing vibration measurement signals representing vibrational movements of the pipe arrangement. Both the excitation arrangement and the sensor arrangement are electrically coupled to the measuring system electronics, which in turn serves to control the transducer, in particular its excitation arrangement, and to receive and evaluate measurement signals supplied thereby, in particular vibration measurement signals supplied by its sensor arrangement, in particular to determine measured values representing at least one measured variable.To protect against external influences, the tube assembly, together with the excitation and sensor assembly, is typically housed in a metallic transducer protective housing, and the measuring system electronics are housed in a protective electronics housing, also made of metal, for example. The latter can also be mounted directly on the aforementioned transducer protective housing, for example, forming a compact Coriolis mass flow / density meter. In the measuring systems shown in WO-A 96 / 08697 or WO-A 2019 / 017891, the transducer protective housing and the tube assembly are, in particular, detachably connected to one another, for example, to enable subsequent insertion of the tube assembly or replacement of a defective or worn tube assembly with an intact one on site.

[0003] The aforementioned pipe arrangements are each intended to be integrated into the course of a process line and each have at least one pipe - for example exactly one pipe or exactly two pipes or exactly four pipes - which extends from a respective first pipe end to a respective second pipe end with a pipe length and has a lumen enclosed by a - typically metallic - pipe wall and extending from the first pipe end to the second pipe end. The pipe, which is at least partially curved and / or at least partially straight, is - due to the measuring principle - designed to flow in or out of the pipe connected via the process line, at least in a flow direction pointing from the first pipe end to the second pipe end.The medium is then discharged and, during this time, is caused to vibrate, for example in order to generate Coriolis forces dependent on the mass flow, inertial forces dependent on the density of the medium and / or frictional forces dependent on the viscosity of the medium. For example, bending vibrations are used to create a static equilibrium. The tubes of commercially available (standard) measuring systems typically have at least two mutually orthogonal planes of symmetry and can, for example, have a U-shaped, V-shaped, rectangular, or triangular shape, and more rarely, an Ω-shaped or helical shape. In addition, their respective tube walls are typically made of a steel, for example stainless steel, duplex steel or super duplex steel, a titanium alloy, a zirconium alloy, for example Zircaloy, and / or a tantalum alloy.The length of such pipes can range between approximately 100 mm and 2000 mm, and the caliber (inner diameter) of such pipes can range between approximately 0.1 mm and approximately 100 mm, typically such that the respective pipe has a caliber-to-pipe length ratio in the range between approximately 0.08 and 0.25. In the case of transducers with a single pipe, this pipe usually communicates with the aforementioned process line via a substantially straight connecting pipe section opening into the inlet side and a substantially straight connecting pipe section opening into the outlet side.Furthermore, the tube arrangement of such measuring transducers with a single tube each comprises at least one single-piece or multi-piece counteroscillator, for example, tubular, box-shaped, or plate-shaped, which is coupled to the tube on the inlet side to form a first coupling zone and which is coupled to the tube on the outlet side to form a second coupling zone, and which, during operation, is essentially at rest or oscillates inversely to the tube, i.e., at the same frequency and in opposite phase. The tube arrangement of such a measuring transducer, formed by the tube and counteroscillator, is usually mounted in the aforementioned protective housing for oscillation solely by means of the two connecting tube pieces through which the tube communicates with the process line during operation.In the (standard) transducers with a single, essentially straight tube, shown, for example, in US-A 52 91 792, US-A 57 96 010, US-A 59 45 609, US-B 70 77 014, US-A 2007 / 0119264, WO-A 01 / 02816, or WO-A 99 / 40394, the tube and the counteroscillator are aligned essentially coaxially with each other, as is quite common in conventional transducers. The materials used for the counteroscillators are usually comparatively inexpensive steel grades, such as structural steel or free-cutting steel, especially when titanium, tantalum, or zirconium are used for the tube.In the case of transducers with two or more tubes, the respective tube arrangement typically has an inlet-side flow divider extending between the tubes and an inlet-side connection flange, as well as an outlet-side flow divider extending between the tubes and an outlet-side connection flange, via which the tube arrangement can be integrated into the process line. Pipe arrangements shown in US-A 2012 / 0123705, US-A 56 02 345, US-A 59 26 096, WO-A 2009 / 136943, WO-A 87 / 06691, WO-A 96 / 05484, WO-A 96 / 08697, WO-A 97 / 26508, WO-A 99 / 39164 or WO-A 2019 / 017891 each have two pipes, namely a first pipe and a second pipe of identical construction and parallel thereto, as well as a first flow divider with exactly two flow openings - serving here as a line branch or on the inlet side - and a first flow divider with exactly two flow openings that is identical to the first flow divider - serving here as a line union oroutlet-side - second flow splitter with exactly two flow openings, whereas in US-A 56 02 345, WO-A 96 / 08697 or US-A 2017 / 0356777 or WO-A 2019 / 081169 or WO-A 2019 / 081170 or the aforementioned patent application PCT / EP2019 / 082044 the pipe arrangements shown each have a first flow splitter - serving here as a line branch or on the inlet side - with exactly two flow openings, a second flow splitter structurally identical to the first flow splitter - serving here as a line connection or on the outlet side - with exactly two flow openings and two pipes, namely a first pipe and a second pipe. In addition, each of the two orfour pipes are connected to each of the first and second flow dividers in such a way that the first pipe opens with its first end into a first flow opening of the first flow divider and with its second end into a first flow opening of the second flow divider, the second pipe opens with its first end into a second flow opening of the first flow divider and with its second end into a second flow opening of the second flow divider.that the first tube opens with its first end into a first flow opening of the first flow divider and with its second end into a first flow opening of the second flow divider, the second tube opens with its first end into a second flow opening of the first flow divider and with its second end into a second flow opening of the second flow divider, the third tube opens with its first end into a third flow opening of the first flow divider and with its second end into a third flow opening of the second flow divider and the fourth tube opens with its first end into a fourth flow opening of the first flow divider and with its second end into a fourth flow opening of the second flow divider. The flow dividers of commercially available measuring transducers are also typically designed as an integral component of the aforementioned protective transducer housing.

[0004] In order to generate vibration signals influenced by the respective measured variable to be measured or corresponding thereto, the at least one tube of the measuring transducer is actively excited by means of the excitation arrangement during operation of the measuring system to vibrate in a vibration form suitable for measuring the respective measured variable or generating the aforementioned Coriolis, inertial or friction forces, occasionally also referred to as drive or useful mode, and the corresponding vibration responses, namely the resulting vibration movements of the at least one tube, are simultaneously recorded by means of the sensor arrangement.

[0005] To excite mechanical vibrations of the at least one tube, the exciter arrangement comprises at least one electromechanical, typically electrodynamic, vibration exciter, which is partially mechanically connected to the tube and configured to convert electrical power into mechanical power using a time-varying electrical current, such that a time-varying drive force acts on the tube at a drive point formed by the vibration exciter on the mechanically connected tube. For the aforementioned case in which the tube arrangement comprises at least one further (second) tube, the at least one vibration exciter can also be partially attached thereto, such that the vibration exciter acts differentially on the two tubes.For the other aforementioned case, in which the pipe arrangement has a counter-oscillator, the vibration exciter can be partially attached thereto in such a way that the vibration exciter acts differentially on the pipe and the counter-oscillator. However, the vibration exciter can also be partially attached to the aforementioned transducer protective housing, for example. In the case of transducers of conventional (standard) measuring systems, the at least one vibration exciter is typically designed and arranged such that the driving force generated thereby acts practically only at a point on the respective pipe, or that a line of action of the driving force generated thereby runs essentially perpendicular to a normal of a drive cross-sectional area, namely a cross-sectional area of the pipe enclosed by an imaginary circumferential line passing through the aforementioned drive point.In the case of (standard) measuring transducers of commercially available (standard) measuring systems, the excitation arrangements, as shown, inter alia, in US-A 56 02 345, US-A 57 96 010, US-B 68 40 109, US-B 70 77 014 or US-B 70 17 424, US-A 2014 / 0352454, WO-A 93 / 01472, WO-A 2005 / 050145, WO-A 2013 / 002759, WO-A 2011 / 019345, are typically also designed in such a way that each of the tubes is (proportionately) connected to exactly one vibration exciter, in such a way that the excitation arrangement, apart from the (one) vibration exciter, does not have any other vibration exciter connected to the respective tube. connected vibration exciter.Not least for this (standard) case, the vibration exciter is typically of the electrodynamic type, namely formed by means of a voice coil, for example in such a way that its magnetic armature is mechanically connected to the at least one tube to form the drive point and that its air coil, which is flooded by the magnetic field of the armature, is electrically connected to the measuring system electronics and mechanically connected to the other tube or the counter-oscillator of the tube arrangement or to the transducer protective housing.Nevertheless, vibronic measuring systems are also known, for example from WO-A 2017 / 069749, WO-A 2017 / 019016, WO-A 2006 / 036139, US-A 59 26 096, WO-A 99 / 28708, WO-A 99 / 44018, WO-A 99 / 02945, US-A 2020 / 0132529, US-A 48 31 885, US-B 65 57 422, US-A 60 92 429 or also US-A 48 23 614, in which the exciter arrangement has two or more vibration exciters each connected to one and the same of the tubes of the respective tube arrangement and / or formed by means of one or more piezo elements.

[0006] To detect vibrations of the at least one pipe, the sensor arrangement comprises at least two vibration sensors, for example electrodynamic or optical, of which a first vibration sensor is positioned on the inlet side of the pipe, spaced apart from the vibration exciter in the direction of flow, and a second vibration sensor—typically identical in construction to the first vibration sensor—is positioned on the outlet side of the pipe, spaced apart from the vibration exciter in the direction of flow. Each of the at least two vibration sensors is also configured to detect vibrational movements of the pipe and to convert them into a first or second vibration measurement signal representing the same vibrational movements, in particular an electrical or optical one, for example, using an electrical voltage dependent on the vibrations of the pipe.In the case of electrodynamic vibration sensors, these can, for example, each be formed by means of a moving coil electrically connected to the measuring system electronics, for example in such a way that its magnetic armature is mechanically connected to the at least one tube and that its air coil, which is flooded by the magnetic field of the armature, is electrically connected to the measuring system electronics and mechanically connected to the other tube or the counter-oscillator of the tube arrangement or to the converter protection housing.

[0007] The measuring system electronics of each of the aforementioned measuring systems is also designed to energize the at least one vibration exciter during operation according to the useful mode to be excited, namely to feed electrical power into the at least one vibration exciter by means of at least one electrical drive signal having a time-varying electrical current, e.g., with an electrical current regulated with regard to (alternating current) frequency, phase angle, and amplitude, such that the pipe executes forced mechanical vibrations, for example, bending vibrations, with one or more vibration frequencies predetermined by the drive signal, typically corresponding to one or more resonance frequencies of the at least one pipe; this, for example, also with a constantly regulated vibration amplitude.The drive signal can be configured as a harmonic sinusoidal signal, namely a sinusoidal signal having exactly one (AC) frequency, or, for example, as a multifrequency signal, namely a signal containing multiple signal components with differing (AC) frequencies. Consequently, each of the first and second vibration measurement signals supplied by the sensor arrangement also contains one or more sinusoidal signal components, each with a frequency corresponding to a vibration frequency of vibrational movements of the pipe, such that each of the first and second vibration signals also has at least one useful signal component, namely a sinusoidal signal component with a (signal) frequency corresponding to the first useful frequency.Accordingly, the measuring system electronics are also configured to provide the aforementioned driver signal for the vibration exciter at least temporarily with a sinusoidal (useful) current having an (alternating current) frequency, such that the at least one tube at least partially or predominantly executes useful vibrations, namely mechanical vibrations forced by the (energized) vibration exciter with a useful frequency, namely an (oscillation) frequency corresponding to the aforementioned (alternating current) frequency.

[0008] In measuring systems of the type in question, the useful mode is typically one or more of a multitude of natural vibration modes inherent in the pipe, each having an associated resonance frequency, in particular one or more symmetrical vibration modes, in which the pipe can or does execute oscillation movements having an odd number of vibration antinodes and a correspondingly even number of vibration nodes. Not least because of their particular suitability for measuring both the mass flow and the density and viscosity of the flowing medium, one or more natural symmetrical bending vibration modes are preferably used as the useful mode in such measuring systems, especially in commercially available standard measuring systems.For curved pipes, a symmetrical bending vibration mode is typically selected as the useful mode, in which the respective pipe oscillates around a static rest position around an imaginary first vibration axis that imaginarily connects the first and second pipe ends, in the manner of a cantilever clamped only at the ends (. out-of-plane mode ), while in the case of transducers with a straight tube or straight tubes, a symmetrical bending vibration mode is usually chosen as the useful mode, in which the respective tube oscillates around a virtual vibration axis coinciding with one of its main axes of inertia (longitudinal axis) and imaginarily connecting the first and second tube ends, like a clamped string around a static rest position ( in-plane mode). In commercially available measuring systems, the use of the first-order (bending) vibration mode, occasionally referred to as the fundamental vibration mode or f1 mode, in which vibration movements of the pipe each have exactly one antinode and two vibration nodes and are therefore symmetrical, and more rarely the use of the third-order (bending) vibration mode, occasionally referred to as the f3 mode, in which vibration movements of the pipe each have exactly three antinodes and four vibration nodes, has been established as the useful mode.

[0009] For the aforementioned (standard) case that exactly one single vibration exciter is provided per pipe (or per pipe pair), this is always positioned and aligned in such a way that the aforementioned drive cross-sectional area is located as close as possible to half the pipe length, thus at a respective maximum vibration amplitude of each of the aforementioned symmetrical vibration modes or a maximum amplitude of the corresponding useful vibrations, but also at a vibration node of the asymmetrical vibration mode also inherent in the pipe.In order to achieve the highest possible efficiency in exciting the wanted mode, but also to avoid undesired excitation of vibrations in one or more of the aforementioned asymmetric vibration modes, the vibration exciter in commercially available (standard) measuring systems is also positioned in such a way that a drive offset, namely a smallest distance between the drive cross-sectional area of the tube and a predetermined reference cross-sectional area of the at least one tube, located at a maximum amplitude of the vibration movements of the wanted vibrations, is as small as possible, ideally zero. In commercially available (standard) measuring systems, there is also typically a line of intersection between two mutually orthogonal planes of symmetry of the at least one tube or a line perpendicular to the direction of vibration of the vibration movements of the tube in the second-order vibration mode orThe principal axis of inertia of at least one tube relative to the drive force within the aforementioned reference cross-sectional area. In commercially available (standard) measuring systems, the drive offset is actually slightly different from zero, not least due to the various tolerances in the manufacture of the transducers or the components and assemblies required for them. Typically, however, it is less than 5 mm and less than 0.5% of the tube length, and in most cases, less than 2 mm and less than 0.2% of the tube length.

[0010] For the purpose of efficient excitation of the useful mode, the measuring system electronics are also particularly designed to set the (alternating current) frequency determining the useful frequency accordingly so that it corresponds as closely as possible to a resonance frequency (f1) of the first-order oscillation mode or a resonance frequency (f3) of the third-order oscillation mode or deviates from the respective resonance frequency to be set by less than 1% of the same resonance frequency and / or by less than 1 Hz, and thus from the resonance frequency of each of the other natural oscillation modes of the tube by more than 5% of the same resonance frequency and / or by more than 10 Hz, orThe measuring system electronics are also accordingly configured to follow a change in the resonance frequency, for example due to a change in the density of the medium conveyed in the pipe, with a change in the (alternating current) frequency of the driver signal, such that the excited useful oscillations are predominantly resonance oscillations of the at least one pipe. To adjust the (alternating current) frequency, the measuring system electronics of the respective measuring system can, for example, use a phase-locked loop (.), possibly also a digital phase-locked loop (. PLL - phase-locked loop ).

[0011] As a result of the useful vibrations of at least one pipe excited in the manner described above, Coriolis forces which are also dependent on the mass flow are known to be induced in the medium flowing through it, such that Coriolis vibrations, namely additional forced vibrations with a useful frequency, are superimposed on the useful vibrations, which correspond to a natural vibration mode, occasionally also referred to as a Coriolis mode, with an order increased by one compared to the order of the useful mode, and that the useful signal components of the vibration measurement signals follow a change in a mass flow of the medium carried in the pipe with a change in a phase difference of the useful signal components, namely a difference between a phase angle of the useful signal component of the first vibration measurement signal and a phase angle of the useful signal component of the second vibration measurement signal.The measuring system electronics of each of the aforementioned measuring systems are also configured to generate mass flow measurement values representing the mass flow based on the aforementioned phase difference of the useful signal components caused by the tube's oscillations in the Coriolis mode. In commercially available (standard) measuring systems, when the fundamental oscillation mode is used as the useful mode, the second-order antisymmetric oscillation mode typically serves as the Coriolis mode, or when the third-order oscillation mode is used as the useful mode, the fourth-order antisymmetric oscillation mode typically serves as the Coriolis mode.Since the resonance frequency of the vibration mode serving as the wanted mode is particularly dependent on the instantaneous density of the medium, commercially available Coriolis mass flowmeters can be used to directly measure not only the mass flow but also the density of the medium flowing through it based on the (AC) frequency of the drive signal and / or the (signal) frequency of the wanted signal components of the vibration measurement signals. Accordingly, the measuring system electronics of measuring systems of the type in question are typically also configured to generate density measurement values representing the density based on the aforementioned (AC) frequency of the drive signal and / or the signal frequency of the aforementioned wanted signal component of at least one of the vibration signals.Furthermore, it is also possible to directly measure the viscosity of the flowing medium using vibronic measuring systems of the type in question, for example, based on the excitation energy or excitation power required to maintain the useful vibrations and / or based on the damping of the useful vibrations resulting from the dissipation of vibration energy. Furthermore, other derived measurement variables, such as the Reynolds number, can be easily determined from the aforementioned flow and / or material parameters using such vibronic measuring systems.

[0012] As described, inter alia, in the above-mentioned US-A 2007 / 0113678, US-A 2012 / 0123705, US-A 2016 / 0349091, US-A 2016 / 0123836, US-A 2016 / 0138997, US-B 73 92 709, US-B 75 62 586, WO-A 03 / 021205, WO-A 2005 / 050145, WO-A 2011 / 019345, WO-A 2013 / 002759, WO-A 2013 / 009307, WO-A 2017 / 069749, WO-A 93 / 01472, WO-A 99 / 39164 or the German patent application 102019124709.8, vibration-type measuring transducers, and thus the measuring systems formed with them, can be exposed to a multitude of loads during their service life, which usually lasts several years, which can cause considerable deviations of the measuring system from a reference state determined in advance, for example during calibration in the manufacturer's factory and / or when commissioning the measuring system, and thus significantly reduce the measuring accuracy of the measuring system with which it ultimately maps the measured variables to be recorded, not least the mass flow and the density, into the corresponding measured values.Examples of such leading loads which result in irreversible changes to the vibration properties of at least one pipe or the pipe arrangement formed thereby, whether they occur once or repeatedly, are:Examples of possible causes which may occur permanently or only briefly are high (excessive) temperatures, temperature shocks or other thermally induced overloads of the at least one pipe, high pressure surges in the medium to be measured, excessive clamping forces and / or vibration forces exerted on the measuring transducer by the process line and the associated crack formation and / or plastic deformation in the at least one pipe, erosion of the at least one pipe from the inside out caused by the medium carried in the measuring transducer, for example through corrosion and / or abrasion, and thus a reduction in its wall thickness, the formation of a deposit on the inside of the at least one pipe which comes into contact with the medium to be measured, material fatigue or other signs of wear on the at least one pipe. In addition, during the running time of the measuring system, the at least one vibration exciter as well as each of the vibration sensors can also be affected, for example through thermally induced overload orAgeing can lead to changes relevant to the measurement accuracy, for example in such a way that the electrical impedance of the measuring transducer is also changed.

[0013] As a result of such (over)loading of the measuring transducer, it can generally be assumed that one or more of the system functions (transfer functions) inherent in the measuring transducer, each of which characterises a vibration response of the pipe arrangement, for example a functional dependence of the useful vibrations or the vibration measurement signals on the driver signal or one or more functional dependences of the useful vibrations or the vibration measurement signals on the driver signal and the respective flow and / or material parameters of the measured material, are changed in comparison to a (reference) system function inherent in the respective original measuring transducer. An example of such system functions of the measuring transducer is, among others:a mass flow-to-phase difference system function, according to which the aforementioned phase difference of the useful signal components of the vibration measurement signals depends on the mass flow, or a density-to-resonance frequency system function of the transducer, according to which one or more resonance frequencies of the pipe arrangement depend on the density of the medium.Equally affected by such (over)loads of the measuring transducer are the measuring functions of the measuring system involving the aforementioned system functions of the measuring transducer, according to which the measuring system as a whole converts the respective measured variable to be recorded into the respective measured values, for example a mass flow-to-measured value measuring function of the measuring system composed of the aforementioned mass flow-to-phase difference system function of the measuring transducer and a phase difference-to-mass flow measured value characteristic function, namely a characteristic function implemented in the measuring system electronics, according to which a determined phase difference is converted into mass flow measured values, according to which the mass flow measured values determined thereby are dependent on the mass flow.The phase difference to mass flow measured value characteristic function can, for example, be a (linear) parameter function with a (scale) zero point corresponding to a phase difference of the useful signal components measured when the medium is at rest, and a (measurement) sensitivity that corresponds to a change in the phase difference of the useful signal components related to a change in the mass flow (slope of the characteristic function). Further examples of such system functions or measurement functions formed thereby can include a density to resonant frequency system function of the measuring transducer or a density to measured value (measurement) function of the measuring system involving this and a resonant frequency to density measured value characteristic function of the measuring system electronics and / or a viscosity to damping system function of the measuring transducer orThis, as well as a damping-to-viscosity measured value characteristic function of the measuring system electronics, is called the viscosity-to-measured value (measurement) function of the measuring system. The change in the respective system function can accordingly result, for example, in a drift of one or more of the respective characteristic parameters of one or more of the aforementioned characteristic functions, in the case of a linear parameter function, for example, of the zero point and / or its gradient.

[0014] The aforementioned change to one or more of the system functions of the transducer or one or more of the measuring functions of the measuring system can occasionally also lead to the transducer or the measuring system formed by it functioning so incorrectly that the high measurement accuracy typically sought for such measuring systems is no longer guaranteed, thus significantly impairing the functionality of the measuring system, possibly even suspending it, or resulting in a corresponding malfunction of the affected measuring system. Furthermore, as a result of such overloads, which also affect the structural integrity of the transducer as a whole, there may even be concern about the destruction of the pipe arrangement or the transducer formed by it, leading to leakage or explosion.Such changes, which also affect the operational safety of measuring systems of the type in question, can, for example in the case of toxic and / or highly flammable measuring substances or in the case of gases under high pressure, have catastrophic consequences for the entire process plant and for the persons present therein.

[0015] In view of this, measuring systems of the type in question are usually subjected to recurring checks, for example as part of regular predictive maintenance, in order to be able to initiate appropriate repair measures as quickly as possible if necessary, not least when a malfunction of the measuring system is detected. Such repair measures can, for example, in the event of a permanent reduction in measuring accuracy, include reprogramming resulting in a readjustment of the measuring system electronics or, in the event of wear or mechanical damage to the measuring transducer, its replacement or, as mentioned, among other things, in WO-A 2019 / 017891, a replacement of the tube arrangement. In order to detect such malfunctions of measuring systems of the type in question as early as possible, in particular those caused by a permanent reduction in measuring accuracy and / or an impairment of operational reliability,in US-A 2012 / 0123705, US-A 2010 / 0011882, WO-A 2005 / 050145, WO-A 2013 / 002759, WO-A 2017 / 069749, WO-A 2011 / 019345, WO-A 96 / 05484, WO-A 99 / 39164, US-A 46 80 974, US-A 57 96 010, US-A 57 28 952, US-A 59 26 096, EP 2 638 367 A1 or DE102019124709.8 it is proposed in each case to subject the respective measuring system to a corresponding diagnosis on site on a recurring basis. In particular, the measuring system can be subjected to self-diagnosis – additionally or exclusively – using on-board means, namely solely by means of a measuring transducer and connected measuring system electronics. In order to determine the aforementioned changes in system functions or the associated impairments to the functionality of the measuring system, the pipe can, for example, also be actively tested using the excitation arrangement during a (self-)diagnosis, if necessary.Vibrations can also be stimulated with multimodal vibrations and / or vibrations simultaneous with the useful vibrations, and the vibration measurement signals representing the resulting vibration responses can be evaluated accordingly in the measuring system electronics, namely, they can be examined for faults in the measuring system. For example, parameter values that characterize the respective vibration response or one or more of the aforementioned system functions can be determined based on the vibration measurement signals and compared with the correspondingly specified reference values. For example, in order to generate a system status or fault message that signals this accordingly and, if necessary, also declares an alarm when a correspondingly specified threshold value representing a still acceptable tolerance level is exceeded, thus diagnosing a fault.Parameters characterizing such vibration responses can be, for example, (vibration) amplitude ratios or (vibration) frequency ratios. The (system) parameters characterizing the system functions can, in turn, be, for example, one or more modal bending stiffnesses, one or more modal mass distributions, or even one or more modal dampings of at least one pipe. The corresponding reference values can be determined in advance, for example, during an (initial) calibration of the measuring system by the manufacturer in the factory or, if necessary, during commissioning of the measuring system on-site, using the measuring system itself while still in its original (reference) state, and stored accordingly in the measuring system electronics.

[0016] Suitable vibration modes for (self-)diagnosis in measuring systems of the type in question, not least in standard measuring systems, are those natural vibration modes of the pipe that are equally symmetrical as the respective established useful mode. For example, in the (standard) measuring systems shown in US-A 46 80 974, US-A 57 96 010, US-A 57 28 952, and WO-A 2017 / 069749, resonance vibrations of one or more symmetrical vibration modes, preferably resonance vibrations of first and / or third, and possibly also fifth-order vibration modes, are also excited and evaluated for the respective self-diagnosis. This can also be done, for example, by evaluating free vibrations, namely vibrations that have decayed after an active excitation. Alternatively or in addition, as in US-A 2012 / 0123705 or DE102019124709.8 proposes using non-resonant vibrations, namely vibrations of the pipe forced by the appropriately powered vibration exciter with a vibration frequency deviating from each resonance frequency of the pipe by more than 1 Hz or more than 1%, for (self-)diagnosis, for example, to minimize or eliminate any dependence of the system function of the transducer to be tested on the medium conveyed therein. However, as described in DE102019124709.8, due to the typically very low vibration amplitudes for non-resonant vibrations, this can lead to a very long observation period, namely more than 10,000, possibly even more than 10,000 vibration periods, associated with a high demand for computing power and storage capacity.

[0017] Based on the aforementioned prior art, one object of the invention is to improve vibronic measuring systems of the aforementioned type such that the occurrence of any malfunctions or defects in the measuring system, such as wear or aging phenomena of the respective measuring transducer that reduce the measuring accuracy and / or operational reliability of the measuring system, can be detected as early and reliably as possible, and if necessary, also signaled; this is particularly true when using the (standard) measuring transducers or typical measuring transducer designs established for conventional measuring systems, as well as while largely retaining proven technologies and architectures of already established measuring system electronics.

[0018] To achieve the object, the invention consists in a vibronic measuring system, in particular a Coriolis mass flow meter or Coriolis mass flow / density meter, for measuring and / or monitoring at least one measured variable, in particular a flow parameter, in particular a mass flow and / or a volume flow and / or a flow velocity, and / or a material parameter, in particular a density and / or a viscosity, of a fluid measuring substance, in particular a gas, a liquid or a dispersion.The measuring system according to the invention, designed for example as an in-line measuring device and / or measuring device in a compact design, comprises: a measuring transducer with a pipe arrangement for guiding the flowing medium, with an excitation arrangement for converting electrical power into mechanical power which is useful for exciting and maintaining forced mechanical vibrations of the pipe arrangement and with a sensor arrangement for detecting mechanical vibrations of the pipe arrangement and for providing vibration measurement signals which represent vibration movements of the pipe arrangement, as well as a measuring transducer, namely both with its excitation arrangement and with its sensor arrangement, in particular.Measuring system electronics, electrically coupled by means of electrical connecting lines, for example formed by at least one microprocessor and / or arranged in an electronics protective housing, for controlling the measuring transducer and for evaluating vibration measuring signals supplied by the measuring transducer.

[0019] The measuring system according to the invention further provides that the tube arrangement comprises at least one tube, for example, one that is at least partially curved and / or at least partially straight and / or first. This tube extends from a first tube end to a second tube end with a tube length of, for example, more than 100 mm and has a lumen enclosed by a, for example, metallic, tube wall and extending from the first tube end to the second tube end. This tube is configured to have a measuring medium flow through it at least in a flow direction pointing from the first tube end to the second tube end, and to be vibrated during this flow. The tube naturally contains a plurality of resonance frequencies (f1, f2, ...) each having an associated resonance frequency (f1, f2, ...)., fx) having vibration modes (natural vibration forms), in which the pipe can carry out or carries out vibration movements each having one or more vibration antinodes and two or more vibration nodes, such that vibration movements of the pipe in a fundamental vibration mode, namely a first-order vibration mode (f1 mode), for example a first-order bending vibration mode, have exactly one vibration antinode and two vibration nodes and that vibration movements of the pipe in a higher vibration mode, namely a second-order or higher-order vibration mode (f2 mode, ... fx mode), for example a second-order or higher-order bending vibration mode, have two or more vibration antinodes and three or more vibration nodes.

[0020] In the measuring system according to the invention, it is also provided that the exciter arrangement has a vibration exciter, for example an electrodynamic one, which is mechanically connected to the pipe and is designed to convert electrical power into mechanical power with a time-varying electrical current, such that a time-varying driving force acts on the pipe at a drive point formed by the vibration exciter on the pipe mechanically connected thereto, for example in such a way that Line of actionthe drive force runs perpendicular to a normal of a drive cross-sectional area of the pipe, wherein the vibration exciter is positioned and aligned such that a drive offset, namely a smallest distance between a drive cross-sectional area of the pipe enclosed by an imaginary circumferential line of the pipe passing through the drive point and a predetermined reference cross-sectional area of the at least one pipe, determined for example with an intact or original measuring transducer, is not more than 3°mm, for example less than 2 mm, and / or less than 0.5% of the pipe length, for example namely less than 0.2% of the pipe length, for example namely with an intact ororiginal transducer is equal to zero, wherein a vibration node of said vibration movements, formed between two vibration antinodes of vibration movements of the at least one pipe in a vibration mode (deviating from the first-order vibration mode) (second or higher order), for example (nominally) located at half the pipe length, lies within the reference cross-sectional area.

[0021] In the measuring system according to the invention, it is further provided that the measuring system electronics are configured to energize the vibration exciter, namely to feed electrical power into the vibration exciter by means of an electrical drive signal having a time-varying electrical current, such that the pipe executes forced mechanical vibrations, for example bending vibrations, with one or more vibration frequencies predetermined by the drive signal.

[0022] In the measuring system according to the invention, it is further provided that the sensor arrangement comprises a first vibration sensor, for example an electrodynamic or optical one, which is positioned on the pipe, for example at a distance of more than 10 mm and / or more than one fifth of the pipe length from the vibration exciter in the direction of flow, for example namely at least partially mechanically connected to the pipe, and which is designed to detect vibration movements of the pipe and to convert them into a first vibration measurement signal, for example an electrical or optical one, representing the same vibration movements, for example in such a way that the first vibration measurement signal contains one or more sinusoidal signal components, each with a frequency corresponding to an vibration frequency of vibration movements of the pipe, and that the sensor arrangement comprises at least one second vibration sensor, for example an electrodynamic or optical one, which,for example, more than 10 mm and / or more than one-fifth of the pipe length is spaced apart from the vibration exciter in the direction of flow and / or is positioned on the pipe at a distance from the first vibration sensor in the direction of flow, for example, namely at least partially mechanically connected to the pipe, and is designed to detect vibrational movements of the pipe and to convert them into a second vibration measurement signal, for example, electrical or optical, representing the same vibrational movements, for example in such a way that the second vibration measurement signal contains one or more sinusoidal signal components, each with a frequency corresponding to an vibration frequency of vibrational movements of the pipe.

[0023] In the measuring system according to the invention, it is further provided that the measuring system electronics are configured to receive and evaluate the first and second vibration measurement signals, for example to determine and output the measured values representing at least one measured variable.

[0024] Furthermore, in the measuring system according to the invention, it is further provided that the measuring system electronics are configured to provide the drive signal at least temporarily with a sinusoidal first (useful) current having a first (alternating current) frequency, such that the tube at least partially, for example predominantly, executes first useful oscillations, namely mechanical oscillations forced by the (energized) oscillation exciter with a first useful frequency, namely a (oscillation) frequency corresponding to the first (alternating current) frequency, for example such that the first useful frequency deviates from a resonance frequency, f1, of the fundamental oscillation mode by less than 1% of the same resonance frequency, f1, and / or by less than 1 Hz and / or that the first useful frequency deviates from a resonance frequency, f2, of the second-order oscillation mode by more than 5% of the same resonance frequency, f2,and / or deviates by more than 10 Hz and / or that the first useful oscillations are suitable for causing Coriolis forces in the flowing medium that are dependent on the mass flow, and that each of the first and second oscillation signals each has a first useful signal component, namely a sinusoidal signal component with a (signal) frequency corresponding to the first useful frequency, and also based on at least the first useful signal components, for example based on their (signal) frequency and / or based on an amplitude of at least one of the first useful signal components and / or based on a phase angle of at least one of the first useful signal components, to determine measured values representing at least one measured variable, for example mass flow measured values representing the mass flow of the medium and / or density measured values representing the density of the medium. Furthermore, the measuring system according to the invention also providesthat the measuring system electronics are arranged to provide both the driver signal at least temporarily, for example during a test interval lasting more than 10 ms and / or limited in time and / or repeatedly started, with a sinusoidal second (useful) current having a second (alternating current) frequency, such that the second (alternating current) frequency, , for example, for two or more oscillation periods and / or a period of more than 10 ms, deviates from a resonance frequency, f2, of the second-order vibration mode by less than 1%, for example by less than 0.1%, the same resonance frequency, f2, and / or by less than 1 Hz, for example by less than 0.1 Hz, and that the tube at least partially - for example simultaneously with the first useful vibrations and / or stationary, namely for two or more oscillation periods and / or a period of more than 10 ms, having a constant oscillation amplitude different from zero- second useful oscillations, namely mechanical oscillations forced by the (energized) oscillation exciter at a second useful frequency, namely a (oscillation) frequency corresponding to the second (alternating current) frequency, whereby each of the first and second oscillation signals each has a second useful signal component, namely a sinusoidal signal component with a (signal) frequency corresponding to the second useful frequency, as well as to carry out a (self-)diagnosis of the measuring system based on at least one of the second useful signal components, for example based on its (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components and / or based on a phase angle of at least one of the second useful signal components, for example to check the functionality of the measuring system and / or to (re-)calibrate and / or determine the measuring system,whether there is a malfunction in the measuring system.

[0025] According to a first embodiment of the invention, it is further provided that the first useful frequency deviates from a resonance frequency, f1, of the fundamental oscillation mode by less than 1% of the same resonance frequency, f1, and / or by less than 1 Hz.

[0026] According to a second embodiment of the invention, it is further provided that the first useful frequency deviates from a resonance frequency, fr3, of a third-order vibration mode inherent in the at least one pipe, for example, namely a third-order bending vibration mode, in which vibration mode the vibration movements of the pipe have exactly three antinodes and two vibration nodes, by less than 1% of the same resonance frequency, fr3, and / or by less than 1 Hz, for example, namely the resonance frequency, fr3. Further developing this embodiment of the invention, it is further provided that a first vibration node of vibration movements of the at least one pipe in the third-order vibration mode is located in the first pipe end and a second vibration node of the third-order vibration mode is located in the second pipe end.

[0027] According to a third embodiment of the invention, it is further provided that the harmonic vibration mode corresponds to a second-order vibration mode (f2 mode), for example a second-order bending vibration mode, in which second-order vibration mode the vibration movements of the pipe have exactly two vibration antinodes and three vibration nodes.Further developing this embodiment of the invention, it is further provided that a vibration node of said vibration movements formed between the two vibration antinodes of the vibration movements of the at least one pipe in the second-order vibration mode, for example (nominally) located at half the pipe length, lies within the reference cross-sectional area and / or that a principal axis of inertia of the at least one pipe, which is perpendicular to the vibration direction of the vibration movements of the pipe in the second-order vibration mode, lies within the reference cross-sectional area of the at least one pipe.

[0028] According to a fourth embodiment of the invention, it is further provided that the drive offset corresponds to a distance between a center of gravity (center point) of the drive cross-sectional area of the pipe and a center of gravity (center point) of the reference cross-sectional area of the at least one pipe.

[0029] According to a fifth embodiment of the invention, it is further provided that a line of action of the driving force runs perpendicular to a normal of a driving cross-sectional area of the pipe.

[0030] According to a sixth embodiment of the invention, it is further provided that an intersection line of two mutually orthogonal planes of symmetry of the at least one tube lies within the reference cross-sectional area.

[0031] According to a seventh embodiment of the invention, it is further provided that a main axis of inertia of the at least one tube, which is perpendicular to the driving force, lies within the reference cross-sectional area of the at least one tube.

[0032] According to an eighth embodiment of the invention, it is further provided that the measuring system electronics is configured to provide the second useful current of the driver signal at least temporarily simultaneously with the first (useful) current, for example in such a way that an amplitude of the first (useful) current is set to be not less than an amplitude of the second (useful) current and / or that an amplitude of the second (useful) current is set to be more than 40%, for example not less than 50%, of an amplitude of the first (useful) current.

[0033] According to a ninth embodiment of the invention, it is further provided that the measuring system electronics are configured to set the second (alternating current) frequency as a function of the first (alternating current) frequency, for example in such a way that the second (alternating current) frequency lies within a frequency setting interval, of which an upper interval limit and / or a lower interval limit and / or a center frequency corresponds to a predetermined multiple of the first (alternating current) frequency, for example namely more than 230% of the first (alternating current) frequency and / or less than 300% of the first (alternating current) frequency corresponding multiple of the first (alternating current) frequency.

[0034] According to a tenth embodiment of the invention, it is further provided that the measuring system electronics have a first phase-locked loop (PLL1), for example a digital one, used to set the first (AC) frequency, and that the measuring system electronics have a second phase-locked loop (PLL2), for example a digital one, used to set the second (AC) frequency. Further developing this embodiment of the invention, it is further provided that the measuring system electronics are configured to set a capture range of the second phase-locked loop (PLL2) by means of at least one output signal of the first phase-locked loop (PLL1), for example an output signal of a loop filter of the first phase-locked loop (PLL1), and / or based on the first (AC) frequency.

[0035] According to an eleventh embodiment of the invention, it is further provided that the measuring system electronics are configured to carry out the (self-)diagnosis of the measuring system based on the at least one second useful signal component, for example based on its (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components and / or based on a phase angle of at least one of the second useful signal components: to determine whether and / or to what extent there is a fault in the measuring system, for example a fault that reduces the functionality of the measuring system and / or causes a malfunction of the measuring system and / or reduces the integrity of at least one of the first and second vibration measurement signals or measured values obtained therefrom and / or provokes a measurement error in the measured values obtained therefrom;and / or to determine whether or to what extent the tube arrangement has changed compared to a previously determined reference state, for example namely damaged, and / or to determine whether and / or to what extent there is a malfunction of the measuring system due to one or more vibration properties of the tube arrangement which have changed compared to a previously determined reference state, for example as a result of damage to the tube arrangement, and / or to determine whether and / or to what extent there is damage to the tube arrangement, for example as a result of erosion on an inner side of the tube wall facing the lumen and / or as a result of deposit formation on an inner side of the tube wall facing the lumen, and / or to determine whether and / or to what extent there is a measurement error in the determination of the measured values due to damage to the measuring transducer, for example namely the tube arrangement.

[0036] According to a twelfth embodiment of the invention, it is further provided that the measuring system electronics are set up to carry out the (self-)diagnosis of the measuring system on the basis of the second useful signal components, for example on the basis of their (signal) frequency and / or on the basis of a (signal) amplitude of at least one of the second useful signal components and / or on the basis of a phase angle of at least one of the second useful signal components, to determine whether an existing fault in the measuring system is due to a, for example irreversible, change in one or more flow properties of the pipe arrangement, for example due to a reduction in a flow cross-section of the pipe arrangement, for example as a result of a blockage of one or more of the pipes and / or as a result of a coating on an inner side of the pipe wall of one or more of the pipes.

[0037] According to a thirteenth embodiment of the invention, it is further provided that the measuring system electronics are configured to carry out the (self-)diagnosis of the measuring system based on the second useful signal components, for example based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components and / or based on a phase angle of at least one of the second useful signal components, to determine whether an existing disturbance in the measuring system is due to a, for example irreversible, change in one or more vibration properties of the pipe arrangement, for example due to a reduction in the wall thickness of the pipe wall of one or more of the pipes and / or due to a plastic deformation of one or more of the pipes and / or due to a coating on an inner side of the pipe wall of one or more of the pipes and / or due to a crack in the pipe wall of one or more of the pipes,is due to.,

[0038] According to a fourteenth embodiment of the invention, it is further provided that the measuring system electronics is configured to determine a (modal) deflection of the first useful oscillations corresponding to a (signal) amplitude of one of the first useful signal components, for example a difference between the (signal) amplitudes of the first useful signal components, for example to determine deflection values representing the deflection of the first useful oscillations based on at least one of the oscillation measurement signals.

[0039] According to a fifteenth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine a (modal) deflection of the first useful oscillations corresponding to a (signal) amplitude of one of the second useful signal components, for example a difference between the (signal) amplitudes of the second useful signal components, for example to determine deflection values representing the deflection of the second useful oscillations based on at least one of the oscillation measurement signals.

[0040] According to a sixteenth embodiment of the invention, it is further provided that the measuring system electronics is configured to determine a deflection ratio corresponding to a ratio of a (modal) deflection of the first useful oscillations and a (modal) deflection of the second useful oscillations, for example, to determine deflection ratio values representing the deflection ratio based on at least one of the oscillation measurement signals.

[0041] According to a seventeenth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine a (modal) damping of the first useful oscillations corresponding to a ratio of the (signal) amplitude of one of the first useful signal components, for example a sum or a difference of the (signal) amplitudes of the first useful signal components, and a (signal) amplitude of the first (useful) current, for example to determine damping values representing the damping of the first useful oscillations based on the driver signal and at least one of the oscillation measurement signals.

[0042] According to an eighteenth embodiment of the invention, it is further provided that the measuring system electronics are set up to determine a (modal) damping of the second useful oscillations corresponding to a ratio of the (signal) amplitude of one of the second useful signal components, for example a sum or a difference of the (signal) amplitudes of the second useful signal components, and a (signal) amplitude of the second (useful) current, for example to determine damping values representing the damping of the second useful oscillations based on the driver signal and at least one of the oscillation measurement signals.

[0043] According to a nineteenth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine a damping ratio corresponding to a ratio of the (modal) damping of the first useful vibrations and the (modal) damping of the second useful vibrations, for example, to determine damping ratio values representing the damping ratio based on the driver signal and / or at least one of the vibration measurement signals.

[0044] According to a twentieth embodiment of the invention, it is further provided that the measuring system electronics is configured to determine, based on the driver signal and at least one of the vibration measurement signals, damping values representing a (modal) damping of the second useful vibrations, for example, namely, to compare one or more of the damping values with a reference value (damping reference value) determined in advance for this purpose. Further developing this embodiment of the invention, it is further provided that the measuring system electronics is configured to perform the (self-)diagnosis of the measuring system by comparing one or more of the damping values with at least one reference value (damping reference value) determined in advance and / or by means of an intact measuring system. For example, if one or more of the damping values deviate from the reference value, it is also provided to output a message representing this, for example, declared as a (fault) alarm.and / or that the measuring system electronics are configured to carry out the (self-)diagnosis of the measuring system based on several of the damping values, to determine a temporal change, for example a change trend and / or a change rate and / or a change speed, of the damping of the second useful vibrations, for example, to determine an increasing disturbance as the damping of the second useful vibrations decreases and / or to output a message representing an increase in a disturbance, for example declared as a (fault) alarm, and / or that the measuring system electronics are configured to determine a dispersion measure, for example an empirical variance and / or a range, for damping of the second useful vibrations of the at least one pipe based on a plurality of damping values,for example, to output and / or to compare the dispersion measure with one or more specified reference values for carrying out the (self-)diagnosis of the measuring system.

[0045] According to a twenty-first embodiment of the invention, it is further provided that the measuring system electronics has a non-volatile electronic data memory (EEPROM) which is designed to hold digital data, for example even without an applied operating voltage, for example namely to store one or more previously determined reference values for the measuring system characteristic number, wherein one or more reference values for the measuring system characteristic number, for example previously determined by the manufacturer of the measuring system and / or during manufacture of the measuring system and / or during operation of the measuring system, for example namely one or more reference values representing a reduced functionality of the measuring transducer and / or namely one or more reference values representing a malfunction of the measuring transducer, are stored in the electronic data memory.Developing this embodiment of the invention, it is further provided that the measuring system electronics is configured to compare one or more characteristic values for the measuring system characteristic with one or more reference values for the measuring system characteristic stored in the data memory.

[0046] According to a twenty-second embodiment of the invention, it is further provided that the measuring system electronics is configured to determine the resonance frequency f1 of the first vibration mode of the at least one tube, for example, namely to determine frequency values representing the resonance frequency based on the driver signal and / or at least one of the vibration measurement signals.

[0047] According to a twenty-third embodiment of the invention, it is further provided that the measuring system electronics are configured to determine the resonance frequency f2 of the second vibration mode of the at least one tube, for example, namely to determine frequency values representing the resonance frequency based on the driver signal and / or at least one of the vibration measurement signals.

[0048] According to a twenty-fourth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine a resonance frequency ratio corresponding to a ratio of the resonance frequency of the first vibration mode of the at least one tube and the resonance frequency of the second vibration mode of the at least one tube, for example, namely to determine frequency ratio values representing the resonance frequency ratio based on the first and second (AC) frequencies of the driver signal and / or based on the signal frequencies of the first and second useful signal components of at least one of the vibration measurement signals.

[0049] According to a twenty-fifth embodiment of the invention, it is further provided that the measuring system electronics is configured to determine frequency values representing the resonant frequency of the second vibration mode of the at least one pipe based on the driver signal and / or at least one of the vibration measurement signals, for example to compare one or more of the frequency values with one or more reference values predetermined for this purpose and / or to use several of the frequency values to determine a scatter measure for the resonant frequency of the second vibration mode of the at least one pipe.Developing this embodiment of the invention further, it is further provided that the measuring system electronics is configured to determine a scatter measure for the resonance frequency of the second vibration mode of the at least one pipe on the basis of a plurality of frequency values, for example also to output it and / or to compare the scatter measure with a reference value predetermined for this purpose in order to carry out the (self-)diagnosis of the measuring system and, in the event of a deviation of the scatter measure from the reference value, to output a message representing this.

[0050] According to a twenty-sixth embodiment of the invention, it is further provided that the measuring system electronics is configured to determine, based on the drive signal and / or at least one of the vibration measurement signals, frequency ratio values representing a ratio of the resonant frequency of the first vibration mode of the at least one tube and the resonant frequency of the second vibration mode of the at least one tube, for example, to compare one or more of the frequency ratio values with one or more reference values predetermined for this purpose and / or to use several of the frequency ratio values to determine a measure of dispersion for the resonant frequency ratio of the at least one tube. Further developing this embodiment of the invention, it is further provided that the measuring system electronics is configuredto carry out the (self-)diagnosis of the measuring system, to compare one or more of the frequency ratio values with at least one reference value (frequency ratio reference value) determined in advance for this purpose, for example, to issue a message representing this, for example declared as a (fault) alarm, even if one or more of the frequency ratio values deviate from the reference value, and / or that the measuring system electronics are configured to determine a dispersion measure, for example an empirical variance and / or a range, for the resonance frequency ratio of the at least one pipe based on a plurality of frequency ratio values, for example also to output it and / or to carry out the (self-)diagnosis of the measuring system, to compare the dispersion measure with a reference value predetermined for this purpose and to issue a message representing this in the event of a dispersion measure deviating from the reference value.

[0051] According to a twenty-seventh embodiment of the invention, it is further provided that the measuring system electronics is configured to determine, based on the vibration measurement signals, a phase difference of the second useful signal components, namely a difference between a phase angle of the second useful signal component of the first vibration measurement signal and a phase angle of the second useful signal component of the second vibration measurement signal, phase difference values representing, for example, one or more of the phase difference values with a reference value (phase difference reference value) determined in advance for this purpose and / or to use several of the phase difference values to determine a dispersion measure for the phase difference of the second useful signal components of the at least one pipe. Further developing this embodiment of the invention, it is further provided that the measuring system electronics is configuredto carry out the (self-)diagnosis of the measuring system, to compare one or more of the phase difference values with at least one reference value (phase difference reference value) determined in advance for this purpose, for example, to output a message representing this, for example declared as a (fault) alarm, even if one or more of the phase difference values deviate from the reference value, and / or that the measuring system electronics are set up to determine a dispersion measure, for example an empirical variance and / or a range, for the phase difference of the second useful signal components based on a plurality of phase difference values, for example also to output it and / or to carry out the (self-)diagnosis of the measuring system, to compare the dispersion measure with a reference value predetermined for this purpose and to output a message representing this in the event of a dispersion measure deviating from the reference value.

[0052] According to a twenty-eighth embodiment of the invention, it is further provided that the measuring system electronics are configured to determine, based on at least one of the vibration measurement signals, deflection ratio values representing a ratio of a deflection (amplitude) of the first useful vibrations and a deflection (amplitude) of the second useful vibrations, for example, to compare one or more of the deflection ratio values with one or more reference values predetermined for this purpose and / or to use several of the deflection ratio values to determine a measure of dispersion for the deflection ratio of the at least one pipe. Further developing this embodiment of the invention, it is further provided that the measuring system electronics are configured to compare one or more of the deflection ratio values with at least one reference value (deflection ratio reference value) previously determined for this purpose, in order to carry out the (self-)diagnosis of the measuring system.for example, in the event of a deviation of one or more of the deflection ratio values from the reference value, a message representing this, for example declared as a (fault) alarm, is output, and / or that the measuring system electronics is set up to determine a degree of dispersion, for example an empirical variance and / or a range, for the deflection ratio of the at least one pipe based on a plurality of deflection ratio values, for example also to output it and / or to compare the said degree of dispersion with a reference value specified for this purpose in order to carry out the (self-)diagnosis of the measuring system and to output a message representing this in the event of a deviation of the degree of dispersion from the reference value.

[0053] According to a twenty-ninth embodiment of the invention, it is further provided that the measuring system electronics is configured to provide the second (useful) current (eN2) with a predetermined (current) amplitude. Further developing this embodiment of the invention, it is further provided that the measuring system electronics is configured to carry out the (self-)diagnosis of the measuring system by repeatedly comparing the (signal) amplitude of at least one of the second useful signal components with a reference value (amplitude reference value) that is dependent on the (signal) amplitude of the second (useful) current and / or predetermined for this purpose, for example, namely a (signal) amplitude of the at least one second useful signal component corresponding to the predetermined (current) amplitude of the second (useful) current, for example, to determine whether or to what extent the (signal) amplitude deviates from the same reference value.

[0054] According to a thirtieth embodiment of the invention, it is further provided that the measuring system electronics is set up, for example to carry out the (self-)diagnosis of the measuring system, to calculate one or more characteristic value values for at least one measuring system characteristic, which characterizes an operating state of the measuring system, based on the second useful signal components of at least one of the vibration measurement signals, for example based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components and / or based on a phase angle of at least one of the second useful signal components, for example in such a way that the same measuring system characteristic is dependent on one or more parameters of a system function of the measuring system which mediates between the second useful current component of the driver signal and the second useful signal component of the at least one vibration measurement signal.Further developing this embodiment of the invention, it is further provided that the measuring system electronics is set up to carry out the (self-)diagnosis of the measuring system by comparing one or more key figure values for the measuring system key figure with one or more reference values determined for the measuring system key figure, for example by the manufacturer of the measuring system and / or during manufacture and / or commissioning of the measuring system and / or as a function of the driver signal, for example one or more reference values representing a reduced functionality of the measuring transducer and / or one or more reference values representing a malfunction of the measuring transducer and / or one or more reference values representing a defective measuring transducer, for example to evaluate and / or quantify a deviation of one or more of the key figure values from one or more of the reference values.Furthermore, the measuring system electronics can also be set up to determine whether one or more key figure values for the measuring system key figure are greater than the at least one reference value for the measuring system key figure, for example if one or more key figure values for the measuring system key figure are greater than one or more reference values representing a reduced functionality of the measuring transducer and / or greater than one or more reference values representing a malfunction of the measuring transducer and / or greater than one or more reference values representing a no longer intact measuring transducer, to output a message representing this, for example declared as a (fault) alarm.

[0055] According to a thirty-first embodiment of the invention, it is further provided that the measuring system electronics are configured to follow a change in the density of the medium conveyed in the pipe with a change in the first (alternating current) frequency of the driver signal, and that the measuring system electronics are configured to generate density measurement values representing the density based on the first (alternating current) frequency of the driver signal and / or based on the signal frequency of the first useful signal component of at least one of the oscillation signals.

[0056] According to a thirty-second embodiment of the invention, it is further provided that the first useful signal components of the first and second vibration measurement signals follow a change in a mass flow of the medium carried in the pipe with a change in a phase difference of the first useful signal components, namely a difference between a phase angle of the first useful signal component of the first vibration measurement signal and a phase angle of the first useful signal component of the second vibration measurement signal, and that the measuring system electronics are set up to generate mass flow measurement values representing the mass flow based on the phase difference of the first useful signal components.Further developing this embodiment of the invention, it is further provided that the measuring system electronics is set up, for example to carry out the (self-)diagnosis of the measuring system, to check or calibrate a (mass flow to phase difference) characteristic function of the measuring transducer, according to which the phase difference of the first useful signal components is dependent on the mass flow, and / or a (mass flow to measured value) characteristic function of the measuring system, according to which mass flow measured values determined on the basis of the phase difference of the first useful signal components are dependent on the mass flow, based on the second useful signal components of at least one of the vibration measurement signals, for example based on a phase angle of at least one of the second useful signal components and / or based on a phase difference of the second useful signal components.Furthermore, the measuring system electronics can also be set up, for example to carry out the (self-)diagnosis of the measuring system, to check the (mass flow to phase difference) characteristic function of the measuring transducer, for example a (scale) zero point of the same characteristic function and / or a (measurement) sensitivity of the measuring system, based on a phase difference of the second useful signal components, namely a difference between a phase angle of the second useful signal component (s1N2) of the first vibration measurement signal (s1) and a phase angle of the second useful signal component (s2N2) of the second vibration measurement signal (s2), for example to determine whether or to what extent a drift of the characteristic function or an irreversible change of the (scale) zero point is present.

[0057] According to a thirty-third embodiment of the invention, it is further provided that the measuring system electronics comprises a non-volatile electronic data memory which is designed to retain digital data, for example even without an applied operating voltage, for example to store one or more previously determined reference values for the measuring system characteristic number.

[0058] According to a thirty-fourth embodiment of the invention, it is further provided that the measuring system electronics is configured to provide the driver signal (e1) with the second (useful) current during a test interval, for example, lasting more than 10 ms and / or limited in time and / or recurringly started, with a sinusoidal signal having a second (alternating current) frequency, for example such that the second (useful) current (eN2) is non-volatile or stationary, namely has a (substantially) constant, non-zero amplitude for two or more oscillation periods and / or a period of more than 10 ms (milliseconds).Further developing this embodiment of the invention, it is further provided that the measuring system electronics are configured to determine the measured values representing at least one measured variable during the test interval based on the second useful signal components, for example based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2), and / or that the test interval lasts longer than 100 ms (milliseconds), for example not less than 1 s (second), and / or that the measuring system electronics are configured to automatically start and / or end the test interval, for example recurringly, for example in a time-controlled manner; and / or that the measuring system electronics are configured to receive and execute one or more commands that start the test interval.

[0059] According to a thirty-fifth embodiment of the invention, it is further provided that the pipe wall consists of a steel, for example a stainless steel, duplex steel or super duplex steel, of a titanium alloy and / or a zirconium alloy, for example a Zircaloy, and / or a tantalum alloy.

[0060] According to a thirty-sixth embodiment of the invention, it is further provided that the tube has a caliber (inner tube diameter) that is more than 0.1 mm, for example more than 0.5 mm. Further developing this embodiment of the invention, it is further provided that the tube has a caliber-to-tube length ratio that is more than 0.08, for example more than 0.1, and / or less than 0.25, for example less than 0.2, and / or that the tube length of the tube is more than 200 mm, for example more than 500 mm, and / or less than 2000 mm, for example less than 1500 mm, and / or that the tube has a caliber that is more than 10 mm, for example more than 15 mm.

[0061] According to a thirty-seventh embodiment of the invention, it is further provided that the exciter arrangement does not have any further vibration exciter connected to the pipe apart from the vibration exciter.

[0062] According to a thirty-eighth embodiment of the invention, it is further provided that the vibration exciter is positioned and aligned such that the drive offset is less than 0.5 mm, for example, zero, or that the center of gravity of the drive cross-sectional area of the tube corresponds to or coincides with the drive reference point.

[0063] According to a thirty-ninth embodiment of the invention, it is further provided that each of the first and second order vibration modes of the tube has a first vibration node located in the first tube end of the at least one tube and a second vibration node located in the second tube end of the at least one tube.

[0064] According to a fortieth embodiment of the invention, it is further provided that the tube is curved in sections, for example in a circular arc and / or V-shaped manner, for example in such a way that the tube has a central apex arc segment and / or that exactly one main axis of inertia of the at least one tube lies within the reference cross-sectional area of the at least one tube.

[0065] According to a forty-first embodiment of the invention, it is further provided that the pipe is straight in sections, for example over the entire pipe length, for example in such a way that three main axes of inertia of the at least one pipe lie within the reference cross-sectional area of the at least one pipe and / or a center of mass lies within the reference cross-sectional area of the at least one pipe.

[0066] According to a forty-second embodiment of the invention, it is further provided that the vibration exciter is formed by means of a voice coil, for example having an air coil and an armature.

[0067] According to a forty-third embodiment of the invention, it is further provided that each of the first and second vibration sensors is formed by a plunger coil, for example having an air coil and an armature.

[0068] According to a forty-fourth embodiment of the invention, it is further provided that the vibration exciter has a magnetic armature, formed, for example, by a permanent magnet, and a coil, for example, an air-core coil, through which the magnetic field of the armature flows. Further developing this embodiment of the invention, it is further provided that the magnetic armature is mechanically connected to the at least one tube, forming the drive point, and / or that the coil is electrically connected to the measuring system electronics and configured to receive the drive signal and carry its first and second (useful) currents.

[0069] According to a first development of the invention, it is further provided that the pipe arrangement has at least one second pipe, for example one which is curved at least in sections and / or straight at least in sections and / or identical in construction to the first pipe and / or parallel to the first pipe at least in sections.

[0070] According to a first embodiment of the first further development, it is further provided that the second tube extends from a first tube end to a second tube end with a tube length and has a lumen enclosed by a, for example, metallic, tube wall and extending from the first tube end to the second tube end, and that the second tube is designed to have the medium flowing through it at least in a flow direction pointing from the first tube end to the second tube end, for example at the same time as the first tube, and to be allowed to vibrate during this flow.

[0071] According to a second embodiment of the first further development, it is further provided that the second tube has a plurality of vibration modes (natural vibration modes), each having an associated resonance frequency, in which the second tube can carry out or carries out vibration movements having one or more vibration antinodes and two or more vibration nodes, for example in such a way that vibration movements of the second tube in the second order vibration mode (f1 mode) are opposite, for example inversely equal, to the vibration movements of the first tube in the second order vibration mode (f2 mode) and / or that vibration movements of the second tube in the first order vibration mode (f1 mode) are opposite, for example inversely equal, to the vibration movements of the first tube in the first order vibration mode.Developing this embodiment of the invention, it is further provided that a resonance frequency of the first-order vibration mode of the first tube is equal to a resonance frequency of the first-order vibration mode (f1 mode) of the second tube and that a resonance frequency of the second-order vibration mode of the first tube is equal to a resonance frequency of the second-order vibration mode of the second tube.

[0072] According to a third embodiment of the first further development, it is further provided that the first vibration sensor is positioned on both the first pipe and the second pipe, for example, namely is mechanically connected both partially to the first pipe and partially to the second pipe, and that the first vibration sensor is configured to detect vibration movements, for example, namely opposite vibration movements, of both the first pipe and the second pipe, for example differentially, and to convert them into the first vibration measurement signal, such that the vibration measurement signal represents, for example, opposite vibration movements of the first and second pipes.

[0073] According to a fourth embodiment of the first further development, it is further provided that the second vibration sensor is positioned on both the first pipe and the second pipe, for example, namely is mechanically connected both partially to the first pipe and partially to the second pipe, and that the second vibration sensor is configured to detect vibration movements, for example, namely opposite vibration movements, of both the first pipe and the second pipe, for example differentially, and to convert them into the second vibration measurement signal, such that the vibration measurement signal represents, for example, opposite vibration movements of the first and second pipes.

[0074] According to a fifth embodiment of the first further development, it is further provided that the pipe arrangement has a first flow divider with at least two flow openings, for example serving as a line branch and / or on the inlet side, and that the pipe arrangement has a second flow divider with at least two flow openings, for example identical in construction to the first flow divider and / or serving as a line union and / or on the outlet side.Further developing this embodiment of the invention, it is further provided that each of the first and second tubes of the tube arrangement is connected to each of the first and second flow dividers, for example by forming fluidically parallel flow channels, in such a way that the first tube opens with its first tube end into a first flow opening of the first flow divider and with its second tube end into a first flow opening of the second flow divider and the second tube opens with its first tube end into a second flow opening of the first flow divider and with its second tube end into a second flow opening of the second flow divider.

[0075] According to a sixth embodiment of the first further development, it is further provided that the vibration exciter is mechanically connected both partially to the first pipe and partially to the second pipe.

[0076] According to a seventh embodiment of the first further development, it is further provided that the vibration exciter is configured to act differentially on the first and second tubes, for example in such a way that the first and second tubes simultaneously perform forced mechanical vibrations of the same frequency and opposite to each other, and / or that the vibration exciter is configured to convert electrical power into mechanical power with a time-varying electrical current in such a way that a time-varying driving force acts on the second tube at a drive point formed by the vibration exciter on the second tube mechanically connected thereto, for example simultaneously and / or opposite to the driving force acting on the first tube at the drive point formed by the vibration exciter on the first tube mechanically connected thereto, and / or that the vibration exciter is configuredto simultaneously convert electrical power fed in by means of the electrical drive signal into forced mechanical oscillations of the first and second tubes, for example in such a way that the first and second tubes execute forced mechanical oscillations at the first useful frequency and / or at the second useful frequency simultaneously.

[0077] According to a second development of the invention, the measuring system further comprises an electronics protective housing for the measuring system electronics, for example, attached to a converter protective housing of the measuring converter and / or metallic.

[0078] According to a third development of the invention, the measuring system further comprises a, for example metallic, transducer protective housing, wherein the transducer protective housing and the tube arrangement are fastened to one another, for example detachably.

[0079] A basic idea of the invention is to use vibronic measuring systems of the type in question for the purpose of (self-)diagnosis by means of the at least one vibration exciter to generate useful vibrations, for example bending vibrations, according to such a natural vibration mode of the at least one pipe active, especially non-volatile or stationary,to excite or attempt to excite a vibration which has a vibration node located at the same vibration exciter or in its immediate vicinity. In measuring systems, not least commercially available (standard) measuring systems, with a single vibration exciter acting centrally on the pipe, the aforementioned vibration mode corresponds to a second-order vibration mode, for example a second-order bending vibration mode. Due to the resulting very small drive offset, the aforementioned useful vibrations nominally have only a very small amplitude or no amplitude at all, even when excited at the respective resonance frequency of the vibration mode. On the other hand, however, any change in the drive offset associated with a displacement of the aforementioned vibration node closest to the vibration exciter, for example due to changing geometric or mechanical properties of the pipe orof the resulting measuring transducer relative to the original drive offset, which is effective, for example, for the initial calibration of the measuring system, results in the amplitude changing accordingly for the same excitation compared to the initially measured amplitude; this is particularly true in such a way that as the drive offset increases, the amplitude also increases accordingly. For the purpose of (self-)diagnosis of the measuring system, for example, to check the functionality of the measuring system, the corresponding vibration responses generated by excitation of the second-order vibration mode or the (system) parameters characterizing them can be very easily and repeatedly determined during operation of the measuring system and compared with corresponding reference vibration responses ("fingerprint") or reference values for them, such that increased orDeviations from the corresponding reference values that exceed a specified tolerance level can be detected, and if necessary, signalled as a fault in the measuring system; this can advantageously be done simultaneously with the actual measuring operation without significantly affecting it or without having to interrupt the measuring operation for any lengthy period.

[0080] A further advantage of the invention is that the (self-)diagnosis according to the invention can also be implemented using extensively, if necessary exclusively, the designs proven for conventional vibronic measuring systems, not least for the transducers previously installed therein, as well as maintaining equally extensively proven technologies and architectures of established measuring system electronics; for example, in such a way that conventional, possibly already installed, measuring systems can be retrofitted by appropriately reprogramming the respective measuring system electronics.

[0081] The invention and advantageous embodiments thereof are explained in more detail below using exemplary embodiments illustrated in the figures of the drawing. Identical or similarly acting or functioning parts are provided with the same reference numerals in all figures; where clarity requires it or it otherwise seems expedient, previously mentioned reference numerals are omitted in subsequent figures. Further advantageous embodiments or developments, in particular combinations of partial aspects of the invention initially explained only individually, will become apparent from the figures of the drawing and / or from the claims themselves.

[0082] In detail: Fig. 1 shows a perspective side view of an embodiment of a vibronic measuring system; Fig. 2 shows a block diagram of an embodiment of a vibronic measuring system according to Fig. 1suitable vibration type measuring transducer and a measuring system electronics electrically coupled thereto; Fig. 3 schematically shows in the form of a block diagram a further embodiment of a vibronic measuring system according to Fig. 1 suitable vibration type measuring transducer and electrically coupled measuring system electronics; Fig. 4a schematically shows a tube arrangement of a vibronic measuring system according to Fig. 1 suitable vibration type transducer with a tube excited to first useful vibrations; Fig. 4b schematically with a tube arrangement according to Fig. 4 Mass flow dependent Coriolis oscillations of the tube, excited by useful oscillations; Fig. 5 schematically shows a diagram of a tube of a tube arrangement according to Fig. 4 immanent vibration modes of first, second and third order, respectively; Fig. 6, 7 schematically the tube arrangement according to Fig. 4 with tube excited to second useful vibrations;

[0083] In Fig. 1or 2 and 3, exemplary embodiments or design variants for a vibronic measuring system suitable for measuring and / or monitoring at least one, in particular time-varying, measured variable of a fluid, for example at least temporarily flowing and / or at least temporarily two- or multi-phase or inhomogeneous, medium FL are shown schematically, wherein the measured variable can be, for example, a flow parameter, such as a mass flow ṁ, a volume flow and / or a flow velocity, or for example a material parameter, such as a density ρ and / or a viscosity η, of the medium FL. The measuring system is particularly intended or set up to be integrated into the course of a process line carrying a fluid FL serving as a medium - for example a gas, a liquid or a dispersion - and, during operation, from the fluid supplied to or discharged via the process line.The fluid FL is then discharged again and flows through it at least temporarily. Furthermore, the measuring system is designed to determine, in particular, calculate, and / or output the measured values XM that quantify at least one physical measured variable (sequentially in time), possibly also digitally. The process line can be, for example, a pipeline, for example a pipeline of a filling plant, a refueling device, or another industrial facility.

[0084] As in Fig. 1 , 2or 3 respectively or as is readily apparent from their combination, the measuring system comprises a measuring transducer 10 of the vibration type, namely a measuring transducer with a tube arrangement formed by at least one (first) or more tubes for guiding the measuring medium, an excitation arrangement (31) for converting electrical power in the excitation and maintenance of forced mechanical vibrations of the at least one tube and a sensor arrangement (41, 42) for detecting mechanical vibrations of the tube arrangement and for providing vibration measuring signals (s1, s2), for example electrical or optical, representing vibration movements of the tube arrangement, in particular of its one or more tubes.In addition, the measuring system further comprises a measuring system electronics 20 which is electrically coupled to the measuring transducer 10, namely both to the aforementioned excitation arrangement of the measuring transducer and to the aforementioned sensor arrangement of the measuring transducer, for example by means of corresponding electrical connecting lines, in particular formed by means of at least one microprocessor (µC) and / or arranged in an electronics protective housing (200) and / or serving as a transmitter, for controlling the measuring transducer, in particular namely for causing the aforementioned mechanical vibrations of the at least one pipe, and for evaluating vibration measurement signals supplied by the measuring transducer, for example namely for determining the aforementioned measured values.

[0085] According to a further embodiment of the invention, the measuring system further comprises a support frame 100, in particular a support frame which is rigid and / or torsion-resistant, wherein - as in Fig. 1 , 2or 3 schematically shown - namely support frame 100 and the pipe arrangement are fastened to one another, for example, materially or detachably. To protect the measuring transducer or its components from harmful environmental influences, to avoid undesirable sound emissions from the vibrating pipes, or to collect medium escaping from a leaking pipe arrangement, as is quite common in vibronic measuring systems of the type in question, the aforementioned support frame 100 can also be designed as a transducer protective housing enclosing the pipe arrangement together with the excitation and sensor arrangement, for example also in such a way that the transducer protective housing is metallic and / or has a compressive strength that is greater than a maximum compressive strength of at least one pipe of the pipe arrangement and / or that is more than 50 bar.Furthermore, the measuring system electronics 20 can also be accommodated within a metallic electronics protective housing 200, for example, which is attached to the aforementioned support frame or converter protective housing of the measuring converter, as is quite common in measuring systems of the type in question.

[0086] The at least one tube of the tube arrangement can be straight at least in sections, in particular hollow-cylindrical, and / or curved at least in sections, for example such that the tube has a central apex arc segment, in particular is essentially V-shaped or has a V-shaped silhouette, and / or that the tube as a result has a tube shape lying in a single (tube) plane. As in Fig. 2As indicated, the at least one pipe extends from a first pipe end to a second pipe end with a pipe length corresponding to a length of an imaginary center line of the pipe, for example more than 100 mm, and the pipe has a lumen enclosed by a pipe wall and extending from the first pipe end to the second pipe end. According to a further embodiment of the invention, the pipe length of the pipe is more than 200 mm, for example more than 500 mm, and / or less than 2000 mm, for example less than 1500 mm. In the case of a pipe that is curved at least in sections, the aforementioned pipe length corresponds to a stretched or unwound length of the pipe and the pipe can be manufactured by bending a tubular semi-finished product. According to a further embodiment of the invention, the pipe wall of the at least one pipe consists of a metal, for example namely a steel, in particular.a stainless steel, duplex steel or super duplex steel, a titanium alloy and / or a zirconium alloy, in particular a Zircaloy, and / or a tantalum alloy and / or a nickel-based alloy. In addition, the at least one tube of the tube arrangement can be formed in one piece, for example in such a way that the tube is seamless or (at least in the case of a tube wall made of metal) with a single welded seam. According to a further embodiment of the invention, the at least one tube of the tube arrangement has a caliber (inner tube diameter) that is more than 0.1 mm, for example even more than 0.5 mm, and / or the tube wall of the at least one tube has a minimum wall thickness that is not less than 0.5 mm, for example even more than 1.5 mm, in particular in such a way that the wall thickness of the tube wall is essentially uniform.According to a further embodiment of the invention, the tube has a caliber-to-tube length ratio of more than 0.08, in particular more than 0.1, and / or less than 0.25, in particular less than 0.2. The at least one tube or each of the tubes of the tube arrangement can also assume any other of the geometric shapes and / or dimensions customary in conventional (standard) vibronic measuring systems, for example, 1 mm, 2 mm, 5 mm, 10 mm, 15 mm, or even more, and / or be made of other materials customary for this purpose.

[0087] According to a further embodiment of the invention, the tube arrangement of the measuring transducer 10 - as in Fig. 3 schematically shown - at least one second tube 112. The tube 112 can be curved at least in sections and / or straight at least in sections. In addition, the tube 112 - as in Fig. 3indicated - for example, also be constructed identically to tube 111 and / or arranged at least partially parallel to tube 111. Tube 112 extends, like tube 111, from a first tube end to a second tube end with a tube length and, like tube 111, has a lumen enclosed by a, for example, metallic, tube wall and extending from the first tube end to the second tube end. In addition, tube 112 is also designed to be flowed through by the measuring medium or a partial volume thereof, at least in a flow direction pointing from the first tube end to the second tube end, in particular simultaneously with the first tube, and to be caused to vibrate during this flow. In addition, the tube arrangement can further comprise a first flow divider 21, which here serves, for example, as a line branch and / or is on the inlet side, with at least two flow openings and a,for example, the aforementioned flow divider 21 can have a second flow divider 22 which is structurally identical and / or serves as a line connection and / or is on the outlet side and also has at least two flow openings, and each of the tubes 111, 112 of the tube arrangement can then be connected to each of the first and second flow dividers to form two fluidically parallel flow channels, for example in such a way that the first end of the tube 111 opens into a first flow opening 21a of the flow divider 21 and the second end of the tube opens into a first flow opening 22a of the flow divider 22, and that the first end of the tube 112 opens into a second flow opening 21b of the flow divider 21 and the second end of the tube opens into a second flow opening 22b of the flow divider 22. The length of the tube 111 can, for example, be equal to the length of the tube 112. Furthermore, the pipe arrangement can include additional pipes,for example, namely two further tubes, thus, as shown, among other things, in the aforementioned US-A 56 02 345, WO-A 96 / 08697, US-A 2017 / 0356777, WO-A 2019 / 081169 or WO-A 2019 / 081170, a total of four tubes. Accordingly, both the flow divider 21 and the flow divider 22 can each have, in particular exactly, four flow openings, and each of the tubes of the tube arrangement can be connected to each of the flow dividers 21, 22 to form four fluidically parallel flow paths. For the aforementioned case in which the tube arrangement has four tubes, the tubes can, for example, also be designed such that they are only structurally identical in pairs, for example the tube lengths are only selected to be the same in pairs. In addition, in the case described above that the pipe arrangement comprises two or more pipes,the wall of each of the tubes - as is quite common with tube arrangements of the type in question or with measuring transducers or measuring systems formed thereby - may, for example, be made of the same material; this may, for example, also be such that the tube wall of each of the tubes in the tube arrangement has a wall thickness equal to the wall thickness of the other tube or each of the other tubes and / or that each of the tubes in the tube arrangement has a caliber, namely an inner diameter, equal to the caliber of the other tube or each of the other tubes.

[0088] The pipe arrangement or the measuring transducer MW formed thereby is, as already indicated, specifically intended to be connected to the aforementioned process line via an inlet end 10+ of the pipe arrangement or the measuring transducer MW, for example, enclosed by a first connecting flange, and a corresponding outlet end 10#, for example, enclosed by a second connecting flange, and to be flowed through by the medium FL during operation. A sealing surface can also be formed on each of the aforementioned connecting flanges.In the aforementioned case that the pipe arrangement has at least two pipes and the two flow dividers connected thereto, the inlet end 10+ of the pipe arrangement is formed by means of the flow divider 21 and the outlet end 10# of the pipe arrangement is formed by means of the flow divider 22, and accordingly the flow divider 21 can have the aforementioned first connection flange and the flow divider 22 can have the aforementioned second connection flange. In addition, the at least one pipe of the pipe arrangement is further configured to carry the measured substance FL or a partial volume thereof in its lumen and to be vibrated during this process, for example, namely - in particularForced mechanical oscillations, which cause a measuring effect corresponding to the at least one measured variable and / or are excited by the excitation arrangement, in order to execute a corresponding static rest position; this is done in particular by vibrating the at least one tube of the tube arrangement and, during this time, flowing medium from its first tube end towards its second tube end (flow direction). The aforementioned forced mechanical oscillations can, as is quite common with measuring transducers of the type in question, be at least partially forced bending oscillations of the at least one tube about an imaginary oscillation axis of the tube arrangement, for example an oscillation axis imaginarily connecting the first and second tube ends.

[0089] The aforementioned excitation arrangement of the measuring transducer 10 is in turn particularly intended or arranged to convert electrical power fed thereto (from the measuring system electronics 20) into mechanical power in such a way that - as in Fig. 4a indicated or also from a summary of the Fig. 2 and 4awithout further ado - the at least one pipe 111 of the pipe arrangement and / or each of its pipes carries out at least temporarily forced mechanical oscillations about a respective static rest position, while the sensor arrangement is provided or configured to detect mechanical oscillations of the pipe arrangement, not least mechanical oscillations and / or bending oscillations of the at least one pipe forced by the excitation arrangement, and to provide a first oscillation measurement signal s1 and a second oscillation measurement signal s2, of which - for example electrical - oscillation measurement signals s1, s2 each at least partially represents oscillatory movements of one or more of the pipes of the pipe arrangement, for example in each case by means of a respective variable electrical voltage corresponding to oscillatory movements (X s1 , X s2 ) of the at least one pipe; this in particular in such a way that - as in Fig. 4bschematically shown - the vibration measurement signals s1, s2 (or in each case a spectral signal component s1N1 or s2N1 thereof) follow a change in a mass flow of the medium guided in the pipe arrangement with a change in a first phase difference (Δφ12), namely a change in a difference between a phase angle of the vibration measurement signal s1 and a phase angle of the vibration measurement signal s2, and / or in such a way that each of the aforementioned vibration measurement signals s1, s2 follows a change in a density of the medium guided in the pipe arrangement with a change in a respective signal frequency of at least one spectral signal component.

[0090] The exciter arrangement of the measuring system according to the invention comprises a vibration exciter 31, for example an electrodynamic one, which is mechanically connected to the at least one tube and is also designed to convert electrical power into mechanical power with a time-varying electrical current, such that - as in Fig. 2 indicated or from a summary of the Fig. 2 and 4a immediately apparent - a time-varying drive force F exc1 acts on the pipe at a drive point formed by the same vibration exciter 31 on the pipe mechanically connected thereto. An imaginary circumferential line of the pipe passing through the aforementioned drive point encloses a cross-sectional area of the pipe, which is also referred to below as the drive cross-sectional area of the pipe. According to a further embodiment of the invention, the vibration exciter 31 is positioned such that - as shown in Fig. 4aindicated - a line of action of the aforementioned drive force F exc1 runs perpendicular to a normal of the drive cross-sectional area of the tube. According to a further embodiment of the invention, the vibration exciter 31 is of the electrodynamic type, namely formed by a voice coil, for example, having an air coil and an armature, or the vibration exciter 31 has a magnetic armature, for example, formed by a permanent magnet, and a coil through which the magnetic field of the armature flows, for example, namely an air coil. The magnetic armature can, for example, be mechanically connected to the at least one tube 111 to form the drive point, and / or the coil can, for example, be electrically connected to the measuring system electronics 20.

[0091] For the aforementioned case in which the pipe arrangement comprises two pipes, according to a further embodiment of the invention, the vibration exciter 31 is configured to excite mechanical vibrations of the two pipes 111, 112 simultaneously; this is done in particular in such a way that the vibration exciter 31 acts differentially on the two pipes 111, 112, namely, it can and does introduce only opposing excitation forces into the two pipes 111, 112, for example, such that the first and second pipes 111, 112 simultaneously execute opposite, forced mechanical vibrations of the same frequency. Accordingly, the vibration exciter 31 can, for example, be mechanically connected to both the pipe 111 and the pipe 112, for example, such that the aforementioned driving force acts on both the pipe 111 and the pipe 112.According to a further embodiment of the invention, the vibration exciter 31 is configured to convert electrical power into mechanical power using a time-varying electrical current such that a time-varying drive force acts on the second tube at a drive point formed by the vibration exciter 31 on the second tube mechanically connected thereto, in particular simultaneously and / or oppositely to the drive force acting on the tube 111 at the drive point formed by the vibration exciter 31 on the tube 111 mechanically connected thereto. According to a further embodiment of the invention, it is further provided that the exciter arrangement, as is also customary, for example, in conventional (standard) vibronic measuring systems, has no further vibration exciter connected to the tube other than the vibration exciter 31.

[0092] The sensor arrangement of the measuring system according to the invention has - as in Fig. 2schematically shown - a first vibration sensor 41, in particular an electrodynamic or optical one, and a second vibration sensor 42, in particular an electrodynamic or optical one. Each of the vibration sensors 41, 42, for example even if they are of identical construction, is positioned on the pipe, in particular namely at least partially mechanically connected to the pipe, and is also configured to detect vibrational movements of the at least one pipe and to convert them into a first or second vibration measurement signal, for example an electrical or optical one, representing the same vibrational movements; this is done in particular in such a way that each of the first and second vibration measurement signals contains one or more sinusoidal signal components, each with a frequency corresponding to an vibration frequency of vibrational movements of the pipe.According to a further embodiment of the invention, it is further provided that each of the vibration sensors 41, 42 is positioned on the pipe at a distance from the vibration exciter 31 in the direction of flow, in particular by more than 10 mm and / or more than one fifth of the pipe length and / or the same distance; this in particular in such a way that the vibration sensors 41, 42 are positioned on the pipe at a distance from one another in the direction of flow, as is usual with conventional vibronic (standard) measuring systems. According to a further embodiment of the invention, each of the first and second vibration sensors 41, 42 is each formed by a moving coil, for example having an air coil and an armature. For the aforementioned case in which the pipe arrangement has at least two pipes, each of the vibration sensors 41, 42 can be positioned on both the first pipe 111 and the second pipe 112, in particular bynamely, be mechanically connected both proportionally to the first pipe and proportionally to the second pipe, and each of the vibration sensors 41, 42 can also be configured to detect vibration movements, in particular opposing vibration movements, of both the first pipe and the second pipe, in particular differentially, and to convert them into the first or second vibration measurement signal, such that each of the vibration measurement signals, in particular opposing vibration movements, represents vibration movements of the first and second pipes 111, 112 (. Fig. 3); this particularly also applies to the aforementioned case in which the vibration sensors 41, 42 are each electrodynamic vibration sensors constructed in the manner of a moving coil. For the aforementioned case in which the pipe arrangement has two pipes, according to a further embodiment of the invention, each of the first and second vibration sensors is positioned on both the first pipe and the second pipe, for example, namely, it is mechanically connected both partially to the first pipe and partially to the second pipe. In addition, each of the first and second vibration sensors is configured to detect vibration movements, for example, opposite vibration movements, of both the first pipe and the second pipe and to convert them into the respective first or second vibration measurement signal, such that each of the first and second vibration measurement signals represents vibration movements of the first and second pipes.The vibration sensors can be designed in particular in such a way that vibration movements, not least also opposite vibration movements of the pipes, are detected differentially and / or that each of the first and second vibration measurement signals represents opposite vibration movements of the first and second pipes.

[0093] The at least one tube or each of the tubes of the tube arrangement naturally has a plurality of vibration modes (natural vibration modes), each having an associated resonance frequency (f1, f2, ..., fx), in which the tube can execute or executes vibration movements having one or more vibration nodes (SB) and two or more vibration nodes (SK), such that the number of vibration nodes is exactly one greater than the number of associated vibration nodes. Vibration movements of the respective tube in a fundamental vibration mode, namely a first-order vibration mode (f1 mode), for example a first-order bending vibration mode, have - as also in Fig. 5indicated - exactly one antinode and accordingly two nodes (f1 mode: 1SB, 2SK), while vibration movements of the respective pipe in a higher vibration mode (deviating from the fundamental vibration mode), namely a second or higher order vibration mode (f2 mode, f3 mode, f4 mode, ... fx mode), for example namely a bending vibration mode of second, third, fourth or higher order, accordingly have two or more antinodes and accordingly three or more nodes (f2 mode: 2SB, 3SK, f3 mode: 3SB, 4SK, f4 mode: 4SB, 5SK,..., fx mode: x·SB, [x+1]·SK). Each of the aforementioned vibration modes of the tube, thus also the vibration modes of the first, second and third order (f1 mode, f2 mode, f3 mode) has a first vibration node located in the first tube end of the at least one tube and a second vibration node located in the second tube end of the at least one tube ( Fig. 5). In the aforementioned case that the tube arrangement has two (or more) tubes, the second tube 112 also has a plurality of vibration modes, each having an associated resonance frequency, in which the second tube (like the tube 111) can execute one or more vibration antinodes and two or more vibration nodes.carries out; this, for example, in such a way that - upon appropriate excitation - oscillatory movements of the tube 112 in the first-order oscillation mode (f1 mode) are opposite to, for example even opposite to, the oscillatory movements of the tube 111 in its first-order oscillation mode (f1 mode) and / or that - upon appropriate excitation - oscillatory movements of the tube 112 in the second-order oscillation mode (f2 mode) are opposite to, for example even opposite to, the oscillatory movements of the tube 111 in its second-order oscillation mode. According to a further embodiment of the invention, the tube arrangement is further designed such that - at least with the original or intact measuring transducer - a resonance frequency f1 of the first-order oscillation mode of the tube 111 is equal to a resonance frequency of the first-order oscillation mode (f1 mode) of the tube 112 and / or that - at least nominally, namely with the original orintact transducer - a resonance frequency f2 of the second-order vibration mode of the tube 111 is equal to a resonance frequency of the second-order vibration mode of the tube 112. In addition, for the aforementioned case in which the tube arrangement has two or more tubes and as is also quite common in conventional vibronic (standard) measuring systems, the tube arrangement can also have coupler elements useful for adjusting vibration properties of the tube arrangement, not least for tuning one or more resonance frequencies of its tubes; this in particular in such a way that, as also in . Fig. 3indicated, a first coupler element 23, for example plate-shaped, is mechanically connected to each of the tubes and is positioned further away from the flow divider 22 than from the flow divider 21, and that at least one second coupler element 24, for example plate-shaped and / or structurally identical to the coupler element 23, is mechanically connected to each of the tubes and is positioned further away from the flow divider 21 than from the flow divider 22.

[0094] In the measuring system according to the invention, the vibration exciter 31 is positioned and aligned so that - as in Fig. 4aor 6 and is also quite common in conventional vibronic (standard) measuring systems - a drive offset ΔE, namely a smallest distance between the aforementioned drive cross-sectional area of the tube 111 and a predetermined reference cross-sectional area of the at least one tube, is not more than 3°mm and / or less than 0.5% of the tube length, wherein the reference cross-sectional area is in turn selected or determined in such a way, for example, namely with an intact or original measuring transducer, that a vibration node of the said vibration movements formed between two vibration antinodes of vibration movements of the at least one tube in a higher vibration mode, for example, namely the second order vibration mode, and / or located (nominally) at half the tube length, lies within the reference cross-sectional area.The drive offset ΔE thus practically corresponds to a distance between a center of gravity (center point) of the drive cross-sectional area of the tube and a center of gravity (center point) of the reference cross-sectional area of the at least one tube. According to a further embodiment of the invention, the reference cross-sectional area of the at least one tube is also selected such that a main axis of inertia of the same tube, which is perpendicular to the aforementioned drive force, and / or a line of intersection between two mutually orthogonal planes of symmetry of the same tube lies within the reference cross-sectional area. Moreover, according to a further embodiment of the invention, the tube arrangement and excitation arrangement are designed such that the drive offset ΔE - at least nominally or initially, thus with an intact or original measuring transducer and as, among other things,also quite common in conventional vibronic (standard) measuring systems - is only slightly larger than zero, namely less than 2 mm, for example less than 1 mm, and / or less than 0.2% of the pipe length; in the case of ideal or completely symmetrical pipe and sensor arrangements also such that the drive offset is zero (ΔE = 0), thus the centroid of the drive cross-sectional area of the pipe corresponds as far as possible to the centroid of the reference cross-sectional area or coincides with it.For the aforementioned case that the at least one tube is curved at least in sections, for example, namely at least in sections circularly arcuate and / or substantially V-shaped, the at least one tube 111 can also be designed and the aforementioned reference cross-sectional area can be selected such that exactly one principal axis of inertia of the at least one tube lies within the reference cross-sectional area of the same tube. For the other case, that the at least one tube is straight over the entire tube length, the aforementioned reference cross-sectional area can in turn be selected such that each of the three principal axes of inertia of the at least one tube lies within the reference cross-sectional area of the at least one tube or that a center of mass lies within the reference cross-sectional area of the at least one tube.According to a further embodiment of the invention, the reference cross-sectional area is selected such that a vibration node of said vibration movements formed between the two vibration antinodes of the vibration movements of the at least one pipe in the aforementioned second-order vibration mode, in particular the second-order bending vibration mode, and / or a principal axis of inertia of the at least one pipe perpendicular to the vibration direction of the vibration movements of the pipe in the same second-order vibration mode lies within the reference cross-sectional area of the at least one pipe.

[0095] As already mentioned, in addition to the measuring transducer 10, the measuring system comprises measuring system electronics 20 which is electrically coupled to the transducer, in particular to both its excitation arrangement and its sensor arrangement. The measuring system electronics 20 can, for example, be designed to be programmable and / or remotely parameterizable, for example by means of at least one microprocessor and / or at least one digital signal processor (DSP) and / or by means of a programmable logic module (FPGA) and / or by means of a customer-specific programmed logic module (ASIC). Furthermore, the measuring system electronics 20 can be supplied with the electrical energy required during operation by means of internal energy storage devices and / or from outside the measuring system electronics 20 via a connecting cable. The electrical coupling orThe measuring transducer 10 can be connected to the measuring system electronics 20 using appropriate electrical connecting cables and corresponding cable bushings. The connecting cables can be designed, at least in part, as electrical conductors, at least partially covered by electrical insulation, e.g., as twisted-pair cables, ribbon cables, and / or coaxial cables. Alternatively or additionally, the connecting cables can also be formed, at least in part, by conductor tracks of a printed circuit board, especially a flexible one, possibly coated. The measuring system electronics 20 can also—as shown in FIG. Fig. 1schematically shown - for example, in a corresponding, in particular impact- and / or explosion-proof and / or at least splash-proof, dedicated electronics protective housing 200 and also be designed so that, during operation of the measuring system, it can exchange measurement and / or other operating data, for example also status messages, with a higher-level (not shown here) electronic (measurement) data processing system, for example a programmable logic controller (PLC), a process control system (PCS), a remote control terminal (RTU), or a monitoring control and data acquisition system (SCADA) running on a personal computer (PC) and / or a workstation, via a data transmission system, for example a fieldbus system and / or wirelessly via radio, such as current measured values or setting and / or diagnostic values used to control the measuring system ( Fig. 2or 3). Accordingly, the measuring system electronics 20 can, for example, have such a transmitting and receiving circuit COM, which is powered during operation by a (central) evaluation and supply unit provided in the aforementioned data processing system and remote from the measuring system. For example, the measuring system electronics 20 (or its aforementioned transmitting and receiving circuit COM) can also be designed such that it is electrically connectable to the aforementioned external electronic data processing system via a two-wire connection 2L, possibly also configured as a 4-20 mA current loop, and can thereby draw the electrical power required for the operation of the measuring system from the aforementioned evaluation and supply unit of the data processing system and, if necessary,digitized measured values can be transmitted to the data processing system, for example by (load) modulation of a direct current supply fed by the evaluation and supply unit. In addition, the measuring system electronics 20 can also be designed such that it can be nominally operated with a maximum power of 1 W or less and / or is intrinsically safe. The measuring system electronics 20 can also be constructed in a modular manner, for example, such that various electronic components of the measuring system electronics 20, such as a measuring and evaluation circuit DSV, formed for example by one or more microprocessors and / or by one or more digital signal processors, for processing and evaluating the measurement signals provided by the measuring transducer 10, not least the vibration measurement signals, a driver circuit Exc for controlling the measuring transducer 10 orwhose excitation arrangement, an internal power supply circuit VS for providing one or more internal operating voltages, and / or the aforementioned transmitting and receiving circuit COM for communication with the aforementioned higher-level (measurement) data processing system or the aforementioned external fieldbus, are each arranged on one or more separate circuit boards and / or are each formed by one or more separate microprocessors. As can be seen from the . Fig. 2or 3, the aforementioned transmitting and receiving circuit COM can, for example, also be provided for the output (xm) of measured values (XM) determined internally, for example, by the aforementioned measuring and control circuit DSV, measuring system. Accordingly, the transmitting and receiving circuit COM can also be configured to convert received measured values XM into an output signal xm providing the same measured values XM, for example, conforming to an industry standard, for example DIN IEC 60381-1:1985-11, IEC 61784-1 CPF1 (Foundation Fieldbus), IEC 61784-1 CPF3 (Profibus), IEC 61158 or IEC 61784-1 CPF9 (HART).To visualize measured values (XM) generated internally by the measuring system and / or status messages generated internally by the measuring system, such as an error message or an alarm, on site, the measuring system can furthermore have a display and operating element HMI that communicates at least temporarily with the measuring system electronics 20, such as an LCD, OLED or TFT display placed in the aforementioned electronics housing 200 behind a correspondingly provided window therein, as well as a corresponding input keyboard and / or a touchscreen. In the event that the measuring system has the aforementioned support frame 100, which is designed as a converter protective housing, the electronics protective housing 200, as also in . Fig. 1 , 2 and 3 each shown schematically or easily apparent from their overview, for example, attached to the same support structure.

[0096] In the measuring system according to the invention, the measuring system electronics 20 are particularly configured to energize the vibration exciter 31, namely, to feed electrical power into the vibration exciter 31 by means of an electrical drive signal e1 having a time-varying electrical current, such that the at least one tube executes forced mechanical vibrations, for example, bending vibrations, at one or more vibration frequencies predetermined by the drive signal e1. Furthermore, the measuring system electronics 20 are configured to generate the drive signal e1 at least temporarily, for example, during normal measuring operation orduring a measuring interval, with a sinusoidal first (useful) current eN1 having a first (alternating current) frequency f eN1 , such that the at least one tube at least partially, for example also predominantly, first useful oscillations, namely mechanical oscillations forced by the oscillation exciter 31 (energized with the (useful) current eN1) or a first driving force (component) F exc1 generated thereby, with a first useful frequency f N1 , namely an (oscillation) frequency corresponding to the first (alternating current) frequency f eN1 (f N1 = f eN1 ), and that as a result the oscillation signal s1 has a first useful signal component s1N1 and the oscillation signal s2 has a first useful signal component s2N1, namely a sinusoidal signal component with a (signal) frequency f corresponding to the first useful frequency f N1 s1N1 orf s2N1 (f s1N1 = f s2N1 = f N1 ); this in particular in such a way that the first useful frequency f N1 deviates from a resonance frequency f2 of the second order oscillation mode (f2 mode) by more than 5% of the same resonance frequency f2 ( | f2 - f N1 | > 0.05 f2) and / or by more than 10 Hz ( | f2 - f N1 | > 10 Hz) and / or in such a way that the first useful oscillations are suitable for causing Coriolis forces F c in the medium flowing through the at least one tube or the tube arrangement formed thereby, which Coriolis forces are dependent on the mass flow thereof.Accordingly, the measuring system electronics can further be configured to adjust the first (useful) current eN1 of the driver signal, as is quite common in vibronic measuring systems of the type in question, such that, due to the first useful oscillations excited thereby, Coriolis oscillations dependent on the mass flow are also forced and, as a result, the useful signal components s1N1; s2N1 of the vibration measurement signals s1, s2 follow a change in a mass flow of the medium conveyed in at least one pipe with a change in a phase difference of the first useful signal components of the vibration measurement signals s1, s2, namely a difference between a phase angle of the first useful signal component s1N1 and a phase angle of the first useful signal component s2N1.For the aforementioned case in which the tube arrangement comprises at least two tubes, the vibration exciter 31 can also be configured to simultaneously convert electrical power supplied by the electrical drive signal e1 into forced mechanical vibrations of the first and second tubes 111, 112; this is particularly also done in such a way that the first and second tubes 111, 112 execute forced mechanical vibrations at the first useful frequency f N1 simultaneously, for example, namely, oscillating in opposite directions. For the aforementioned case in which the vibration exciter 31 is formed by a coil electrically connected to the measuring system electronics, energizing the vibration exciter 31 means that the coil receives the drive signal e1, namely, carries its current.

[0097] The aforementioned (alternating current) frequency of the useful current components eN1, thus the first useful frequency f N1, can, for example, correspond to a resonance frequency of the tube arrangement which also depends on the density of the medium FL guided in the tube arrangement - for example, namely a lowest resonance frequency of the tube 111 or the resonance frequency f1 of the fundamental oscillation mode (f1 mode). Accordingly, according to a further embodiment of the invention, the measuring system electronics 20 is further configured to set the first (alternating current) frequency such that the same (alternating current) frequency or the useful frequency f N1 deviates from the resonance frequency f1 of the fundamental oscillation mode by less than 1% of the same resonance frequency f1 (| f1 - f N1 | < 0.01 f1) and / or by less than 1 Hz (| f1 - f N1 | < 1 Hz), for example, namely corresponds to the resonance frequency f1 of the fundamental oscillation mode (f1 mode), orthat, as a result, the oscillation movements of the first useful oscillations correspond to those of the fundamental oscillation mode (f1 mode) of the at least one tube 111. According to another embodiment of the invention, the measuring system electronics are configured to set the first (alternating current) frequency such that the same (alternating current) frequency or the useful frequency f N1 deviates from a resonance frequency f3 of the third-order oscillation mode (f3 mode) by less than 1% of the same resonance frequency f3 (| f3 - f N1 | < 0.01 f3) and / or by less than 1 Hz (| f3 - f N1 | < 1 Hz), for example, namely corresponds to the resonance frequency f3 of the third-order oscillation mode (f3 mode), or that, as a result, the oscillation movements of the first useful oscillations correspond to those of the third-order oscillation mode (f3 mode) of the at least one tube 111.

[0098] To generate the driver signal e1, the measuring system electronics 20 can - as is quite common in such measuring systems - use a corresponding phase-locked loop ( PLL - phase-locked loop ) formed driver circuits Exc.

[0099] The measuring system electronics 20 is, as already indicated, furthermore particularly also provided for receiving and evaluating the vibration measurement signals s1, s2 generated by the measuring transducer 10, in particular for determining and outputting the measured values XM representing at least one measured variable. In particular, the measuring system electronics 20 is configured to use at least the first useful signal components s1N1, s2N1, for example, based on their (signal) frequency and / or based on an amplitude of at least one of the useful signal components s1N1, s2N1 and / or based on a phase angle of at least one of the useful signal components s1N1 ors2N1, to determine measured values representing at least one measured quantity, for example to generate mass flow measured values representing the mass flow of the measured substance and / or density measured values representing the density of the measured substance; This also applies, for example, to measuring systems of the type in question, not least also to those from the above-mentioned US-A 2006 / 0266129, US-A 2007 / 0113678, US-A 2010 / 0011882, US-A 2012 / 0123705, US-A 2017 / 0356777, US-A 56 02 345, US-A 59 26 096, WO-A 2009 / 136943, WO-A 2019 / 017891, WO-A 2019 / 081169, WO-A 2019 / 081170, WO-A 87 / 06691, WO-A 96 / 05484, WO-A 96 / 08697, WO-A 97 / 26508, WO-A 99 / 39164 or the own unpublished international patent application PCT / EP2019 / 082044 in a manner typical of measuring systems known.According to a further embodiment of the invention, the measuring system electronics 20 is accordingly further configured to generate mass flow measurement values representing the mass flow based on the aforementioned phase difference of the first useful signal components s1N1; s2N1, for example by means of a phase difference to mass flow measurement value characteristic function programmed into the measuring system electronics, namely a characteristic function of the measuring system electronics, optionally also designed as a (linear) parameter function, according to which a determined phase difference is converted into mass flow measurement values X m.According to a further embodiment of the invention, the measuring system electronics 20 is additionally configured to determine the resonance frequency f1 of the first vibration mode (f1 mode) of the at least one tube, for example, namely to determine frequency values X f1 representing the resonance frequency f1 based on the drive signal e1 and / or at least one of the vibration measurement signals s1, s2; this is also done, for example, in order to calculate density measurement values X ρ representing the density based on such frequency values, for example according to a corresponding resonance frequency-to-density measurement value characteristic function of the measuring system electronics. Alternatively or additionally, the measuring system electronics 20 can also be provided orbe configured to generate viscosity measurement values, namely measurement values representing the viscosity of the medium FL, based on at least one of the vibration measurement signals s1, s2, and / or the driver signal e1, for example according to a damping-to-viscosity measurement value characteristic function of the measuring system electronics. The processing of the vibration measurement signals s1, s2, and possibly also the control of the aforementioned driver circuit(s) Exc, which is quite common in such measuring systems, can - as also in . Fig. 2 or 3, each shown schematically - for example, also by means of the aforementioned measuring and evaluation circuit DSV.

[0100] The program codes executed during operation of the measuring system in the measuring system electronics 20, for example in one or more of the aforementioned microprocessors or digital signal processors of the measuring system electronics 20, can each be stored persistently, for example, in one or more non-volatile data memories (EEPROMs) of the measuring system electronics 20, which digital data can be retained even without an applied operating voltage, and can be loaded when the same is started into a volatile data memory (RAM) provided in the measuring system electronics 20 or the aforementioned measuring and evaluation circuit DSV, for example, integrated in the microprocessor. The vibration measurement signals s1, s2 are intended for processing in the microprocessor orin the digital signal processor by means of corresponding analog-to-digital converters (A / D), of course first to be converted into corresponding digital signals, for example by digitizing the respective signal voltage of each of the - here electrical - vibration measurement signals s1, s2 in a suitable manner, cf. for example the US-B 63 11 136 mentioned at the beginning. Accordingly, in the measuring system electronics 20, for example in the aforementioned measuring and evaluation circuit DSV, corresponding analog-to-digital converters for the vibration measurement signals s1, s2 and / or at least one non-volatile electronic data memory EEPROM can be provided, which is set up to store digital data, for example even without an applied operating voltage. To further improve the accuracy with which the measured values XM are ultimately determined, the measuring transducer can - as also in . Fig. 2or 3, respectively, are each shown schematically and, as is quite common with such measuring systems, furthermore also have temperature sensors 71 (71, 72) which are used to record temperatures within the pipe arrangement and to provide one or more corresponding temperature measuring signals θ1 (θ1, θ2), for example each mounted directly on at least one pipe of the pipe arrangement, and / or have strain sensors which are used to record mechanical stresses within the pipe arrangement and to provide one or more corresponding strain measuring signals, for example each mounted directly on one of the pipes of the pipe arrangement, and the measuring system electronics can furthermore be set up to receive and process the temperature or strain measuring signals, in particular to use them in determining the measured values.

[0101] As already mentioned, vibration-type measuring transducers, and thus the vibronic measuring systems formed with them, can be exposed to a variety of loads during their service life, which can cause significant deviations of the measuring transducer or the measuring system from a previously determined reference state, for example a respective initial delivery state and / or a state when the measuring system is commissioned on site. This can happen in particular that the pipe arrangement, for example due to overloading, is damaged to such an extent that the vibration properties of at least one pipe change, or that the measuring transducer as a whole is damaged because, among other things, one or more system functions (transfer functions) inherent in the measuring transducer or measurement functions correspondingly formed in the measuring system are deviated from a respective (reference) system function of the original measuring transducer or(Reference) measuring function of the measuring system are changed accordingly. Changes in the vibration properties of the at least one pipe can, for example, be due to changes in one or more modal bending stiffness, mass and / or damping, each of which determines one of the aforementioned vibration modes, and can result in one or more (natural) vibration modes deviating from their respective counterparts when the measuring transducer is in the reference state; this usually also in such a way that an original - typically essentially homogeneous or uniform - distribution of the aforementioned (system) parameters (modal) bending stiffness, (modal) mass and (modal) damping is changed, namely becomes increasingly unevenly distributed. As a result, such loads not only lead to a change in the natural orNot only the resonance frequency of one or more of the aforementioned vibration modes, but in particular also the shape of the vibration movements of the respective vibration modes is subject to changes, such that the position of one or more of the vibration nodes located between two antinodes of vibration movements of the at least one pipe in one or more of its harmonic vibration modes, and thus also the position of the aforementioned reference cross-sectional area, is changed compared to its respective original position. Accordingly, the drive offset determined relative to the reference cross-sectional area also undergoes changes, for example, such that the drive offset increases compared to the drive offset ΔE determined with the original or intact measuring transducer.Furthermore, during the operating time of the measuring system, at least one vibration exciter as well as each of the vibration sensors may be subject to changes relevant to the measuring accuracy, for example due to thermally induced (over)loading or aging, such that the electrical impedance of the measuring transducer is also changed as a result. (Over)loading that can lead to damage to the pipe arrangement or the measuring transducer as a whole can be, for example, high (excessive) temperatures or temperature shocks, excessive pressures or pressure surges in the medium, excessive clamping forces and / or excessive vibration forces exerted on the measuring transducer by the process line, harmful properties of the medium conveyed in the measuring transducer, or even material fatigue, among other things.in a significant reduction in the wall thickness of the pipe wall, for example due to corrosion and / or abrasion of the pipe wall of the at least one pipe caused by the medium, or in a significant reduction in a flow cross-section of the pipe arrangement, for example as a result of at least partial blockage of the pipe arrangement and / or as a result of a solid coating on the inside of the pipe wall in contact with the medium, in a plastic deformation of the at least one pipe or in the formation of cracks within the pipe arrangement, for example in the pipe wall, and thus may even lead to the measuring transducer no longer being safe.

[0102] System functions affected by such damage to the transducer can, for example, correspond to one or more (modal) vibration responses of the pipe arrangement relevant for the measurement of at least one measured variable, for example, a functional dependence of an amplitude of the aforementioned useful vibrations on the driver signal or a functional dependence of an amplitude of the aforementioned Coriolis vibrations on the driver signal and mass flow, or characterize a measuring function involving one or more of the aforementioned vibration responses, according to which the measuring system ultimately converts the respective measured variable to be recorded into the respective measured values. Accordingly, examples of such system functions of the transducer can be a mass flow-to-phase difference system function, namely a system function of the transducer,according to which the aforementioned phase difference of the first useful signal components of the vibration measurement signals depends on the mass flow, one or more resonant frequencies of the pipe arrangement are listed as system functions containing (system) parameters, such as a density-to-resonance frequency system function, for example, a system function of the transducer, according to which the aforementioned resonant frequency f1 depends on the density, or vibration damping as system functions containing (system) parameters, such as a viscosity-to-damping function, for example, a system function of the transducer, according to which damping of the first useful vibrations depends on the viscosity. Accordingly, those measurement functions of the measuring system that are based on one or more of the aforementioned system functions of the transducer may also be affected.For example, a mass flow-to-measured value function involving the mass flow-to-phase difference system function and the aforementioned phase difference-to-mass flow measured value characteristic function of the measuring system electronics, namely a measuring function of the measuring system according to which the mass flow measured values determined thereby are dependent on the mass flow, and / or a density-to-measured value function of the measuring system involving the aforementioned density-to-resonance frequency system function of the measuring transducer and the aforementioned resonance frequency-to-density measured value characteristic function of the measuring system electronics, and / or a viscosity-to-measured value characteristic function of the measuring system involving the aforementioned viscosity-to-damping system function of the measuring transducer and the aforementioned damping-to-viscosity measured value characteristic function of the measuring system electronics.

[0103] Damage to the measuring transducer or its tube arrangement can, in particular, result in one or more system functions or (system) parameters characterising a corresponding measuring function, for example a (scale) zero point and / or a change in the phase difference of the first useful signal components related to a change in the mass flow, corresponding to the (measurement) sensitivity (slope of the characteristic function) of the aforementioned phase difference to mass flow measured value characteristic function, being subject to corresponding temporal changes, in particular drift. As a result of such (over)loading of the measuring transducer, which may occur repeatedly and / or over a longer period of time, the transducer can be damaged to such an extent over the course of its operating life that its functionality or the functionality of the measuring system as a whole is impaired to a considerable extent or even completely.is completely restricted; this can also be the case, for example, in such a way that the result is a disturbance or a malfunction of the measuring system, possibly leading to measurement errors when determining the measured values, for example because the integrity of at least one of the vibration measurement signals or measured values obtained therefrom is significantly reduced, and therefore the measuring accuracy of the measuring system, with which it ultimately maps the measured variable to be recorded into the corresponding measured values, is significantly reduced compared to the initial or nominal measuring accuracy of the original or intact measuring system.

[0104] In order to be able to detect and, if necessary, report any changes to the measuring transducer, for example, in its mechanical properties and / or its electrical properties, or a defect in the measuring transducer or the measuring system formed thereby, as early and as reliably as possible, it is therefore further provided, for example also in the course of a diagnosis of the measuring system carried out by the measuring system itself (self-diagnosis), to actively excite the tube arrangement to mechanical vibrations by means of the excitation arrangement, in such a way that the at least one tube carries out vibrations which - as in Fig. 6 or 7 schematically shown or from their combination with Fig. 5immediately apparent - correspond to the aforementioned second-order vibration mode (f2 mode), and to evaluate the resulting vibration measurement signals accordingly by means of the measuring system electronics 20, in particular to examine them for disturbances in the measuring system; this in particular in such a way that the oscillations corresponding to the second-order oscillation mode (f2 mode) are non-volatile or stationary, namely they have a (substantially) constant oscillation amplitude different from zero for two or more oscillation periods and / or a period of more than 10 ms (milliseconds). For this purpose, the measuring system electronics 20 of the measuring system according to the invention is further configured to at least temporarily generate the driver signal e1 - as also in Fig. 6or 7 respectively - with a second (alternating current) frequency f eN2 having a sinusoidal second (useful) current eN2 - deviating from the first (alternating current) frequency f eN1 by, for example, more than 10 Hz - to provide, such that the at least one tube 111 carries out at least partially (different from the first useful oscillations) second useful oscillations, namely mechanical oscillations forced by the oscillation exciter 31 (energized with the (useful) current eN2) or a second driving force (component) F exc2 generated thereby, with a second useful frequency f N2 , namely an (oscillation) frequency corresponding to the second (alternating current) frequency f eN2 (f N2 = f eN2 ), whereby each of the first and second oscillation signals s1, s2, each has a second Useful signal component s1N2 or s2N2, namely a sinusoidal signal component with a (signal) frequency f s1N2 or corresponding to the second useful frequency f N2.f s2N2 (f s1N2 = f s2N2 = f N2 ). According to a further embodiment of the invention, the measuring system electronics 20 is further configured to provide the aforementioned second (useful) current (eN2) with a predetermined (current) amplitude.

[0105] In the measuring system according to the invention, the measuring system electronics 20 is additionally particularly designed to set the second (alternating current) frequency f eN2 such that it deviates from a resonance frequency f2 of the second-order oscillation mode (f2 mode) of the at least one tube 111 by less than 1% (| f2 - f N2 | < 0.01 f2), for example by less than 0.1%, namely resonance frequency f2, and / or by less than 1 Hz (| f1 - f N2 | < 1 Hz), for example by less than 0.1 Hz; this in particular also in such a way that the (alternating current) frequency f eN2 corresponds to the resonance frequency f2 of the second-order oscillation mode (f2 mode) (f eN2 = f2). Only for the aforementioned, at most with an original or a completely intact measuring transducer orIn the (ideal) case expected by the measuring system, and thus uncritical, that the drive offset ΔE is actually zero, the second useful oscillations would not be excited in this way, and thus the oscillation signals s1, s2 would not have the second useful signal component s1N2 or s2N2 or would have an amplitude of zero; otherwise, however (ΔE <> 0), as a result of such energization of the oscillation exciter 31 with the second (useful) current eN2, the second useful oscillations are actually also excited, and their oscillation movements correspond to those of the second-order oscillation mode (f2 mode) of the at least one tube 111.For the aforementioned case that the tube arrangement has at least two tubes, the vibration exciter 31 can also be configured accordingly to convert electrical power fed in by means of the electrical drive signal e1 into forced mechanical vibrations of the first and second tubes 111, 112 in such a way that the first and second tubes 111, 112 simultaneously execute forced mechanical vibrations at the second useful frequency, for example forced mechanical vibrations at the first useful frequency f N1 and at the second useful frequency f N2 .Accordingly, according to a further embodiment of the invention, the measuring system electronics 20 is further configured to provide the second useful current e1N2 of the driver signal e1 at least temporarily simultaneously with the first (useful) current e1N1; for example, this is also done in such a way that the (current) amplitude of the first (useful) current e1N1 is set to be no smaller than the (current) amplitude of the second (useful) current e1N2 and / or that the (current) amplitude of the second (useful) current e1N2 is set to be more than 40%, for example no less than 50%, of the (current) amplitude of the first (useful) current e1N1.

[0106] Alternatively or additionally, the measuring system electronics are further configured to set the second (AC) frequency f eN2 as a function of the first (AC) frequency f eN1 or as a function of the resonance frequency f1; for example, such that the second (AC) frequency f eN2 lies within a frequency setting interval, of which an upper interval limit and / or a lower interval limit and / or a center frequency corresponds to a predetermined multiple of the first (AC) frequency f eN1, for example, namely a multiple of the first (AC) frequency f eN1 corresponding to more than 230% of the first (AC) frequency f eN1 and / or less than 300% of the first (AC) frequency f eN1.According to a further embodiment of the invention, the measuring system electronics further comprises a first phase-locked loop (PLL1), which can be digital, for example, and a second phase-locked loop (PLL2 ...) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL1) can be digital, for example, and a second phase-locked loop (PLL1) can be digital, for example, and a second phase-locked loop (PLL1) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL1) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-locked loop (PLL2) can be digital, for example, and a second phase-

[0107] The measuring system electronics 20 of the measuring system according to the invention is also designed to use or evaluate at least one of the second useful signal components s1N2, s2N2, for example based on its (signal) frequency and / or based on a - in the case of an electrodynamic vibration sensor, if necessary.also with the (alternating current) frequency f eN2 standardized - (signal) amplitude of at least one of the second useful signal components s1N2, s2N2 and / or based on a phase angle of at least one of the second useful signal components s1N2, s2N2, to carry out a (self-)diagnosis of the measuring system, for example namely to check the functionality of the measuring system and / or to (re-)calibrate the measuring system and / or to determine whether there is a fault in the measuring system, for example such that the functionality of the measuring system is reduced and / or that there is a malfunction of the measuring system and / or there is a measurement error in the determination of the measured values, for example because the integrity of at least one of the vibration measurement signals s1, s2 is reduced.The measuring system electronics can, for example, also be set up to determine in the course of the aforementioned (self-)diagnosis, for example based on the (signal) frequency of the second useful signal components and / or based on a (signal) amplitude of at least one of the second useful signal components s1N2 and / or based on a phase angle of at least one of the second useful signal components s1N2, whether and / or to what extent a fault in the measuring system (. ) due to one or more factors compared to a previously determined reference state ( ) changed vibration properties of the pipe arrangement ( Fig. 7), for example as a result of damage to the pipe arrangement, if necessary, for example, also to determine to what extent damage to the pipe arrangement is due to erosion (corrosion, abrasion) on an inside of the pipe wall facing the lumen or a corresponding reduction in a wall thickness of the pipe wall of the at least one pipe and / or as a result of deposit formation on an inside of the pipe wall facing the lumen and / or due to a crack in the pipe wall of one or more of the pipes and / or due to plastic deformation of one or more of the pipes, and / or to what extent a measurement error is present in the determination of the measured values due to damage to the pipe arrangement.The aforementioned reference state of the measuring transducer can, for example, correspond to its respective state upon delivery from the manufacturer, thus being determined accordingly during calibration in the manufacturer's factory and / or during commissioning of the measuring system and being stored in the measuring system electronics in the form of corresponding reference values for one or more system functions of the measuring transducer specifying (system) parameters.

[0108] The aforementioned evaluation of at least one of the second useful signal components s1N2, s2N2 can, for example, be a simple examination of at least one of the vibration measurement signals s1, s2 for the second useful signal component or a detection of said second useful signal components in the vibration measurement signals s1, s2 above a predetermined (minimum) signal level; however, it can also comprise a dedicated measurement of one or more of the second useful signal components s1N2, s2N2 for their respective (signal) amplitudes or temporal amplitude profiles and / or for their respective phase angles or temporal phase angle profiles and / or for their respective (signal) frequencies or temporal frequency profiles.For example, based on the vibration measurement signals s1, s2, parameter values can be repeatedly determined by the measuring system electronics, which characterize the respective vibration response or one or more of the aforementioned system functions, and compared with correspondingly specified reference values. Alternatively or additionally, based on the vibration measurement signals s1, s2, the measuring system electronics can also be repeatedly calculated, using the measuring system electronics, one or more characteristic values for at least one measuring system characteristic that characterizes an operating state of the measuring system, for example, such that each characteristic value corresponds to a combination of two or more of the aforementioned parameter values or is dependent on several such parameter values.A measuring system characteristic to be determined can also be selected such that it represents a measure of drive offset, such that the measuring system characteristic indicates whether or to what extent the drive offset deviates from an originally existing (initial) drive offset, for example as a result of a change in the position of the centroid of the reference cross-sectional area or a corresponding shift of the reference cross-sectional area, or such that increasing characteristic values quantify a growing drive offset and decreasing characteristic values quantify a decreasing drive offset. Alternatively or additionally, the measuring system characteristic can also be defined, for example, such that it represents a measure of change for how quickly the drive offset changes over time.If a correspondingly specified threshold value is exceeded, for example, a still acceptable tolerance level for a deviation between a determined parameter and / or characteristic value and a respective specified reference value or an impermissibly high deviation, an error can be diagnosed promptly and easily using the measuring system electronics 20, for example, to subsequently generate and output a system status or fault message signaling this accordingly, possibly also declared as an alarm. (System) parameters characterizing vibration responses or system functions can be, for example, (vibration) amplitude ratios or (vibration) frequency ratios, flexural stiffnesses, ratios of modal bending stiffnesses, dampings or ratios of modal dampings of at least one pipe.The corresponding reference values for the parameter and / or key figure values, as well as the respective threshold values, can be determined in advance, for example, during an (initial) calibration of the measuring system by the manufacturer in the factory or, if necessary, during commissioning of the measuring system on-site, using the measuring system itself while still in its original (reference) state and / or based on laboratory measurements with measuring systems of the same design or type. These values can be stored accordingly in advance in the measuring system electronics 20, for example, in its non-volatile EEPROM data memory. The parameter values determined by the measuring system electronics 20 can also be output, for example, displayed on-site and / or forwarded to the aforementioned (measurement) data processing system.

[0109] Taking into account the respectively set first and second useful frequencies, a corresponding resonance frequency ratio of the respective vibration modes can also be determined and used as a (system) parameter specifying a system function of the measuring transducer for (self-)diagnosis, for example in such a way that a time-varying, for example continuously increasing or continuously decreasing, ratio of the resonance frequency f2 to the resonance frequency f1 is used as an indicator for the presence of a fault in the measuring transducer. According to a further embodiment of the invention, the measuring system electronics 20 is accordingly configured to determine the resonance frequency f2 of the second vibration mode (f2 mode) of the at least one tube 111, for example, namely based on the drive signal e1 and / or at least one of the vibration measurement signals s1, s2, frequency values X f2 representing the resonance frequency f2.to determine and / or to determine a resonance frequency ratio f1 / f2 corresponding to a ratio of the resonance frequency f1 of the first oscillation mode (f1 mode) and the resonance frequency f2 of the second oscillation mode (f2 mode), for example based on the first and second (AC) frequencies f eN1 , f eN2 of the driver signal e1 and / or based on the signal frequencies f s1N1 , f s2N1 , f s1N2 , f s2N2 of the useful signal components s1N1, s1N2, s2N1, s2N2 of at least one of the oscillation measurement signals, the frequency ratio values X f12 representing the resonance frequency ratio f1 / f2 (X f12 = f eN1 / f eN2 ; X f12 = f s1N1 / f s1N2 ; X f12 = f s2N1 / f s2N2 ). The recurringly determined frequency ratio values X f12 can be compared with a predetermined reference value for carrying out the (self-)diagnosis of the measuring system by means of the measuring system electronics 20, in particular to determinewhether or to what extent the resonance frequency ratio f1 / f2 deviates from the same reference value.

[0110] Taking into account the deflections (amplitude) of the second useful oscillations, a change in the natural oscillation form of the second-order oscillation mode can also be determined, for example, and used as a (system) parameter specifying a system function of the measuring transducer for (self-)diagnosis.

[0111] According to a further embodiment of the invention, the measuring system electronics 20 is therefore further configured to determine, based on the vibration measurement signals s1, s2, at least one phase difference of the second useful signal components, namely a difference between a phase angle of the second useful signal component s1N2 of the vibration measurement signal s1 and a phase angle of the second useful signal component s2N2 of the vibration measurement signal s2. The repeatedly determined phase difference values can be compared, for example, with one or more predetermined reference values to carry out the (self-)diagnosis of the measuring system by means of the measuring system electronics 20, for example to determine whether or to what extent the phase difference of the second useful signal components or an underlying modal deflection of the second useful vibrations of the at least one pipe deviate from the respective reference value.For example, a phase difference of the second useful signal component that is too high and / or increases continuously over time can be used as an indicator of the presence of a fault. One or more of the aforementioned reference values for the phase difference of the second useful signal component can, for example, also be set as a function of a phase difference of the first useful oscillations that is already being determined for determining the mass flow measured values X m . Alternatively or additionally, the phase difference values determined for the second useful oscillations can also be used to carry out the (self-)diagnosis of the measuring system by means of the measuring system electronics 20 in order to determine a phase difference ratio corresponding to a ratio of the aforementioned phase difference of the second useful oscillations and the phase difference of the first useful oscillations used to determine the mass flow measured values X m .According to another embodiment of the invention, the measuring system electronics 20 is further configured to use the vibration measurement signals s1, s2 to determine at least one of the (signal) amplitudes of the first useful signal components s1N1, s2N1, which in the case of an electrodynamic vibration sensor may also be standardized with the (alternating current) frequency f eN1, and thus amplitude values representing deflections x1 of the first useful vibrations, in particular both the amplitude values X s1N1 representing the (signal) amplitudes of the useful signal components s1N1 and the amplitude values X s2N1 representing the (signal) amplitudes of the useful signal components s2N1, and / or the measuring system electronics 20 is configured to determine at least one of the (signal) amplitudes of the second.

[0112] To determine amplitude values representing useful signal components s1N2, s2N2, and therefore respective deflections x2 of the second useful oscillations, in particular both the (signal) amplitudes of the useful signal components s1N2 representing amplitude values X s1N2 and the (signal) amplitudes of the useful signal components s2N2 representing amplitude values X s2N2, for example by forming a respective moving average for the (signal) amplitudes of the useful signal components s1N1, s1N2, s1N2 and s2N2 by means of an FIR filter and / or by numerical integration of the amplitude values X s1N1, X s2N1, X s1N2 and X s2N2.Alternatively or additionally, the measuring system electronics is further configured to determine a deflection ratio x1 / x2 corresponding to a ratio of the (modal) deflection (amplitude) of the first useful oscillations and the (modal) deflection of the second useful oscillations, for example to determine deflection ratio values representing the deflection ratio x1 / x2 based on at least one of the vibration measurement signals s1, s2, if necessary using the aforementioned deflection values X s1N1 , X s1N2 and / or the aforementioned deflection values X s2N1 , X s2N2 . The repeatedly determined amplitude values, in particularnamely the amplitude values X s1N2 , X s2N2 , and / or the correspondingly determined deflection ratio values can be compared, for example, with one or more reference values predetermined for this purpose in order to carry out the (self-)diagnosis of the measuring system by means of the measuring system electronics 20, for example in order to determine whether or to what extent one and / or more of the (signal) amplitudes or one or more of the modal deflections of the vibrations of the at least one tube, in particular the deflections of the second useful vibrations, deviate from the respective reference value. One or more of the aforementioned reference values for the amplitude values X s1N2 , X s2N2 (or the modal deflections of the oscillations of the at least one tube) can, for example, also be set as a function of a currently set (current) amplitude of the second (useful) current eN2 and / or of one of the current deflection values X s1N1 and / or X s2N1.

[0113] By taking into account both the deflections of the first and second useful vibrations as well as the driving force causing them, it is also possible, for example, to determine a corresponding modal spring stiffness of the respective useful vibrations or the respective vibration mode and to use this as a (system) parameter specifying a system function of the measuring transducer for (self-)diagnosis, for example in such a way that a (modal) spring stiffness of the second useful vibrations that is too low and / or constantly decreasing over time or a ratio of a (modal) spring stiffness c2 of the second useful vibrations to a (modal) spring stiffness c1 of the first useful vibrations that changes over time, for example a constantly increasing or constantly decreasing ratio, is used as an indicator of the presence of a fault. Alternatively or in addition, by taking into account both the deflection velocities of the first and second useful vibrations, it is also possible to determine a corresponding modal spring stiffness of the respective useful vibrations or the respective vibration mode.second useful vibrations as well as the driving force causing them in each case, a (modal) damping of the respective useful vibrations or the corresponding vibration mode can also be determined and used as a (system) parameter specifying a system function of the measuring transducer for (self-)diagnosis, for example in such a way that an excessively high and / or temporally continuously increasing damping of the second useful vibrations or a temporally changing, for example continuously increasing or continuously decreasing, ratio of a (modal) damping d2 of the second useful vibrations to a (modal) damping d1 of the first useful vibrations is used as an indicator for the presence of a fault.

[0114] According to a further embodiment of the invention, the measuring system electronics 20 is therefore further configured to determine a (modal) damping of the second useful oscillations corresponding to a ratio of the (signal) amplitude of one of the second useful signal components s1N2, for example also a sum or a difference of the (signal) amplitudes of the second useful signal components, and a (signal) amplitude of the second (useful) current eN2, for example to determine damping values representing the damping d2 of the second useful oscillations based on the second (useful) current e1N2 and a second useful signal component of at least one of the vibration measurement signals s1, s2. The repeatedly determined damping values can further be compared, for example, with one or more predetermined reference values for carrying out the (self-)diagnosis of the measuring system by means of the measuring system electronics 20, in particular.namely, to determine whether or to what extent the damping of the second useful vibrations of the at least one tube deviates from a predetermined reference value (damping reference value). Alternatively or additionally, the measuring system electronics can also be configured to determine a damping ratio d1 / d2 corresponding to a ratio of the (modal) damping of the first useful vibrations and the (modal) damping d2 of the second useful vibrations, for example, to determine damping ratio values representing the damping ratio d1 / d2 based on the first and second (useful) currents of the driver signal and / or at least the first and second useful signal components of at least one of the vibration measurement signals.Accordingly, the measuring system electronics 20 can also be configured to determine both the aforementioned (modal) damping of the second useful oscillations and a (modal) damping d1 of the first useful oscillations corresponding to a ratio of the (signal) amplitude of one of the first useful signal components s1N1, for example also a sum or a difference of the (signal) amplitudes of the useful signal components s1N1, s2N1, and a (signal) amplitude of the first (useful) current eN1, for example to determine damping values representing the damping of the first useful oscillations based on the driver signal and at least one of the oscillation measurement signals.According to a further embodiment of the invention, the measuring system electronics 20 is further configured to carry out the (self-)diagnosis of the measuring system, to compare one or more of the aforementioned damping values representing the damping of the second useful oscillations and / or one or more of the aforementioned damping ratio values with at least one reference value determined for this purpose in advance and / or by means of an intact measuring system, for example to output a message representing this, in particular declared as a (fault) alarm, even in the event of a deviation of one or more of the damping values from the respective reference value (damping reference value) or a deviation of one or more of the damping ratio values from the respective reference value (damping ratio reference value).According to another embodiment of the invention, the measuring system electronics 20 is further configured to determine spring stiffness values representing the spring stiffness c2 of the second useful vibrations based on the second (useful) current e1N2 and a second signal component of at least one of the vibration measurement signals s1, s2. The repeatedly determined spring stiffness values can be compared, for example, with one or more predetermined reference values for performing the (self-)diagnosis of the measuring system by means of the measuring system electronics 20, in particular to determine whether or to what extent the spring stiffness c2 of the second useful vibrations of the at least one tube deviates from a predetermined reference value (spring stiffness reference value).Alternatively or additionally, the measuring system electronics can also be configured to determine a spring stiffness ratio c1 / c2 corresponding to a ratio of the (modal) spring stiffness c1 of the first useful vibrations and the (modal) spring stiffness c2 of the second useful vibrations, for example to determine spring stiffness ratio values representing the spring stiffness ratio c1 / c2 based on the first and second (useful) currents and / or the first and two useful signal components of at least one of the vibration measurement signals.Accordingly, the measuring system electronics 20 can also be configured to determine both the aforementioned (modal) spring stiffness c2 of the second useful oscillations and a (modal) spring stiffness of the first useful oscillations corresponding to a ratio of the (signal) amplitude of one of the first useful signal components s1N1, for example also a sum or a difference of the (signal) amplitudes of the useful signal components s1N1, s2N1, and a (signal) amplitude of the first (useful) current eN1, for example to determine spring stiffness values representing the spring stiffness c1 of the first useful oscillations based on the first (useful) current e1N1 and the first useful signal component of at least one of the oscillation measurement signals.According to a further embodiment of the invention, the measuring system electronics 20 is further configured to carry out the (self-)diagnosis of the measuring system by comparing one or more of the aforementioned spring stiffness values representing the spring stiffness c2 of the second useful vibrations and / or one or more of the aforementioned spring stiffness ratio values with at least one reference value determined for this purpose in advance and / or by means of an intact measuring system, for example, in the event of a deviation of one or more of the spring stiffness values from the respective reference value (spring stiffness reference value) or a deviation of one or more of the spring stiffness ratio values from the respective reference value (spring stiffness ratio reference value), a message representing this, in particular a message declared as a (fault) alarm.

[0115] The values for one or more of the aforementioned (system) parameters, for example the resonance frequency ratio f1 / f2 of the at least one tube, the deflection ratio x1 / x2 of the first and second useful vibrations, the (modal) damping d2 of the second useful vibrations, the damping ratio d1 / d2 of the first and second useful vibrations, the (modal) spring stiffness d2 of the second useful vibrations, the spring stiffness ratio c1 / c2 of the first and second useful vibrations, etc.The parameter values determined, for example, namely spring stiffness values representing the (modal) spring stiffness c2, spring stiffness ratio values representing the spring stiffness ratio c1 / c2, damping values representing the (modal) damping d2, damping ratio values representing the damping ratio d1 / d2, deflection ratio values representing the deflection ratio x1 / x2, phase difference values representing the phase difference of the second useful signal components, etc., can also be used to repeatedly determine a measure of dispersion for the respective system parameter. Such a measure of dispersion can, for example, be an empirical variance or a range for the respective (system) parameter or the parameter values determined for it.The determined degree of dispersion can also be used for (self-)diagnosis, for example, such that a malfunction of the measuring system is only concluded if the respective (system) parameter has a low degree of dispersion, namely below a correspondingly specified threshold value, and / or that a (system) parameter exhibiting a degree of dispersion above a correspondingly specified threshold value does not trigger a malfunction message, even if a comparison of its parameter values with the respective reference value would initially indicate this. Alternatively or additionally, the degree of dispersion determined by the measuring system electronics 20 can also be output, for example, displayed locally and / or forwarded to the aforementioned (measurement) data processing system.Alternatively or in addition, the parameter values determined for one or more of the aforementioned (system) parameters, for example the resonance frequency ratio f1 / f2 of the at least one pipe, the deflection ratio x1 / x2 of the first and second useful vibrations, the damping of the second useful vibrations, the damping ratio d1 / d2 of the first and second useful vibrations, etc., can also be used to repeatedly determine a temporal change, for example a change trend and / or a change rate and / or a change speed, of the respective (system) parameter.The determined temporal change can also be used for (self-)diagnosis, for example, in such a way that, as the damping of the second useful oscillations decreases or as the resonant frequency ratio f1 / f2 and / or damping ratio d1 / d2 increases with a rate of change within a specified measuring range, an increasing fault in the measuring transducer is detected and / or a message representing an increase in a fault, in particular declared as a (fault) alarm, is output. The temporal change or rate of change or speed of change determined by the measuring system electronics 20 can also be output, for example, displayed locally and / or forwarded to the aforementioned (measurement) data processing system.

[0116] The (self-)diagnosis of the measuring system according to the invention can, for example, be carried out during a test interval reserved for this purpose, for example, one that can also be occasionally repeated or last more than 10 ms (milliseconds), advantageously more than 100 ms, and in particular not less than 1 s (second). The test interval can be limited in time, for example, to less than 1 minute each, but can nevertheless be started repeatedly, for example by command from outside the measuring system and / or automatically, namely time- and / or event-controlled by the measuring system electronics itself. For example, the measuring system electronics can be configured to start the test interval when the medium FL is detected as flowing at a steady state and / or to end it when the medium FL is flowing at an unsteady state or when measuring conditions and / or measured variables are changing rapidly.Accordingly, according to a further embodiment of the invention, the measuring system electronics is capable of automatically starting and / or ending the test interval and / or receiving and executing one or more commands that start the test interval. According to a further embodiment of the invention, the measuring system electronics is further configured to start the test interval during normal measuring operation or during the excitation of the first useful oscillations, such that at least the driver signal e1 is provided with the second (useful) current eN2; this can also be done, for example, such that the driver signal e1 simultaneously contains the first (useful) current eN1, at least temporarily, so that the second useful oscillations are excited simultaneously with the first useful oscillations, and thus the first and second useful oscillations are at least temporarily superimposed on one another during the test interval.According to a further embodiment of the invention, the measuring system electronics is also configured to determine measured values representing at least one measured variable during the test interval based on the second useful signal components s1N2; s2N2, in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components s1N2 and / or based on a phase angle of at least one of the second useful signal components s1N2.

Claims

1. A vibronic measuring system, in particular a Coriolis mass flow meter or Coriolis mass flow / density meter, for measuring and / or monitoring at least one measured variable, in particular a flow parameter, that is to say, in particular a mass flow and / or a volume flow and / or a flow velocity, and / or a substance parameter, that is to say, in particular a density and / or a viscosity, of a fluid measured substance, in particular a gas, a liquid or a dispersion, said measuring system, in particular configured as an in-line measuring device and / or measuring device with a compact design, comprising: - a measuring transducer (10) • with a tube arrangement for conveying the flowing measured substance, • with an exciter arrangement for converting electrical power into mechanical power serving to excite and maintain forced mechanical oscillations of the tube arrangement, • and with a sensor arrangement for registering mechanical oscillations of the tube arrangement and for providing oscillation measurement signals each representing oscillatory movements of the tube arrangement; - and measuring system electronics (20) electrically coupled to the measuring transducer (10), that is to say both to its exciter arrangement and to its sensor arrangement, in particular by means of electrical connecting cables, and formed, in particular, by means of at least one microprocessor and / or arranged in an electronics protective housing, for operating the measuring transducer and for evaluating oscillation measurement signals delivered from the measuring transducer; - wherein the tube arrangement has at least one tube (111), in particular curved at least in sections and / or straight at least in sections and / or a first tube, • said tube (111) extending from a first tube end to a second tube end with a tube length, in particular more than 100 mm, and having a lumen surrounded by an, in particular metal, tube wall extending from the first tube end to the second tube end, • and said tube being configured to have the measured substance flow through it, at least in a flow direction going from the first tube end to the second tube end, and during that to be caused to oscillate, • and wherein a number of oscillation modes (natural modes) each with an associated resonant frequency (f1, f2, ... , fx) are inherent in the tube, in which the tube can execute or executes oscillatory movements with in each case one or more antinodes and in each case two or more nodes in such a way ∘ that oscillatory movements of the tube in a basic oscillation mode, that is to say an oscillation mode of the first order (f1-Mode), that is to say, in particular a bending oscillation mode of the first order, have exactly one antinode and two nodes, ∘ and in such a way that oscillatory movements of the tube in a higher-level oscillation mode, that is to say an oscillation mode of the second order or higher (f2-Mode, ... fx-Mode), that is to say, in particular a bending oscillation mode of the second order or higher, have two or more antinodes and three or more nodes; - wherein the exciter arrangement has an, in particular electrodynamic, oscillation exciter (31) • which is mechanically connected to the tube • and is configured to convert electrical power of a time-variable electrical current into mechanical power in such a way that a time-variable driving force acts on the tube at a drive point formed by means of the oscillation exciter on the tube mechanically connected to it, in particular in such a way that an effective line of the driving force runs perpendicular to a normal of a drive cross-sectional area of the tube, • wherein the oscillation exciter (31) is positioned and aligned in such a way that a drive offset (L1E), that is to say a smallest distance between a drive cross-sectional area of the tube enclosed by an imaginary perimeter of the tube leading through the drive point and a specified reference cross-sectional area of the at least one tube, in particular ascertained with an intact measuring transducer or the original measuring transducer, is not more than 3°mm, in particular less than 2 mm, and / or less than 0.5% of the tube length, that is to say, in particular less than 0.2% of the tube length, that is to say, in particular is equal to zero with an intact measuring transducer or the original measuring transducer, wherein a node of said oscillatory movements formed between two antinodes of oscillatory movements of the at least one tube in an oscillation mode (of the second order or higher) (different from the oscillation mode of the first order), in particular (nominally) located at a half tube length, is inside the reference cross-sectional area, - and wherein the measuring system electronics (20) are configured to supply electrical current to the oscillation exciter (31), that is to say to supply electrical current to the oscillation exciter (31) using an electrical driver signal (e1) having a time-variable electrical current in such a way that the tube executes forced mechanical oscillations, in particular bending oscillations, with one or more oscillation frequencies predetermined by the driver signal (e1); - wherein the sensor arrangement has an, in particular electrodynamic or optical, first oscillation sensor • which is positioned on the tube, in particular in the flow direction spaced more than 10 mm and / or more than one fifth of the tube length away from the oscillation exciter, that is to say, in particular is at least partially mechanically connected to the tube, • and which is configured to detect oscillatory movements of the tube and to convert them into an, in particular electrical or optical, first oscillation measurement signal representing said oscillatory movements, in particular in such a way that the first oscillation measurement signal contains one or more sinusoidal signal components each with a frequency corresponding to an oscillation frequency of oscillatory movements of the tube; - wherein the sensor arrangement has at least an, in particular electrodynamic or optical, second oscillation sensor • which is positioned on the tube, in particular in the flow direction spaced more than 10 mm and / or more than one fifth of the tube length away from the oscillation exciter and / or away from the first oscillation sensor in the flow direction, that is to say, in particular is at least partially mechanically connected to the tube, • and which is configured to detect oscillatory movements of the tube and to convert them into an, in particular electrical or optical, second oscillation measurement signal representing said oscillatory movements, in particular in such a way that the second oscillation measurement signal contains one or more sinusoidal signal components each with a frequency corresponding to an oscillation frequency of oscillatory movements of the tube; - and wherein the measuring system electronics are configured to receive and evaluate the first and second oscillation measurement signals, that is to say, in particular to determine and output measured values representing the at least one measured variable; - wherein the measuring system electronics are configured • both to supply the driver signal (e1) at least occasionally with a sinusoidal first (useful) current (eN1) having a first (alternating current) frequency in such a way ∘ that the tube executes at least partially, in particular predominantly, first useful oscillations, that is to say mechanical oscillations forced by the oscillation exciter (supplied with current) with a first useful frequency, that is to say an (oscillation) frequency corresponding to the first (alternating current) frequency, in particular in such a way that the first useful frequency differs from a resonant frequency, f1, of the basic oscillation mode by less than 1% of said resonant frequency, f1, and / or by less than 1 Hz and / or in such a way that the first useful frequency differs from a resonant frequency, f2,of the oscillation mode of the second order by more than 5% of said resonant frequency, f2, and / or by more than 10 Hz and / or in such a way that the first useful oscillations are suitable for effecting in the flowing measured substance Coriolis forces dependent on the mass flow, ∘ and in such a way that both of the first and second oscillation signals (s1; s2) have in each case a first useful signal component (s1N1; s2N1), that is to say a sinusoidal signal component with a (signal) frequency corresponding to the first useful frequency, • and also to determine measured values representing the at least one measured variable, in particular mass flow measured values representing the mass flow of the measured substance and / or density measured values representing the density of the measured substance based on at least one of the first useful signal components (s1N1; s2N1), in particular based on their (signal) frequency and / or based on an amplitude of at least one of the first useful signal components (s1N1; s2N1) and / or based on a phase angle of at least one of the first useful signal components (s1N1; s2N1), - and wherein the measuring system electronics are configured • both to supply the driver signal (e1) at least occasionally, in particular during a test interval that lasts for more than 10 ms and / or is temporary and / or is restarted repeatedly, with a sinusoidal second (useful) current (eN2) having a second (alternating current) frequency in such a way ∘ that the second (alternating current) frequency differs from a resonant frequency, f2, of the oscillation mode of the second order by less than 1%, in particular by less than 0.1%, of said resonant frequency f2, and / or by less than 1 Hz, in particular by less than 0.1 Hz, in particular for two or more oscillation periods and / or a time period of more than 10 ms, ∘ and in such a way that the tube at least partially executes - in particular simultaneously with the first useful oscillations and / or stationary, that is to say for two or more oscillation periods and / or a time period of more than 10 ms, having a consistent oscillation amplitude that is not zero - second useful oscillations, that is to say mechanical oscillations forced by the oscillation exciter (supplied with current) with a second useful frequency, that is to say an (oscillation) frequency corresponding to the second (alternating current) frequency, whereby both of the first and second oscillation signals in each case have a second useful signal component (s1N2; s2N2), that is to say a sinusoidal signal component with a (signal) frequency corresponding to the second useful frequency, • and also to run a (self-)diagnostics on the measuring system, that is to say, in particular to check an ability of the measuring system to function and / or to (re)calibrate the measuring system and / or to detect whether there is a disturbance of the measuring system based on at least one of the second useful signal components (s1N2; s2N2), in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2).

2. The measuring system as claimed in claim 1, wherein the first useful frequency differs from a resonant frequency, f1, of the basic oscillation mode by less than 1% of said resonant frequency, f1, and / or by less than 1 Hz.

3. The measuring system as claimed in claim 1, wherein the first useful frequency differs from a resonant frequency, fr3, of an oscillation mode of the third order inherent in the at least one tube, that is to say, in particular a bending oscillation mode of the third order, in which oscillation mode the oscillatory movements of the tube have exactly three antinodes and two nodes, by less than 1% of said resonant frequency, fr3, and / or by less than 1 Hz, that is to say, in particular corresponds to the resonant frequency, fr3.

4. The measuring system as claimed in the preceding claim, wherein a first node of oscillatory movements of the at least one tube is located in the first tube end in the oscillation mode of the third order and a second node is located in the second tube end.

5. The measuring system as claimed in one of the preceding claims, wherein the higher-level oscillation mode corresponds to an oscillation mode of the second order (f2-Mode), that is to say, in particular a bending oscillation mode of the second order, in which oscillation mode of the second order the oscillatory movements of the tube have exactly two antinodes and three nodes.

6. The measuring system as claimed in the preceding claim, - wherein a node of the oscillatory movements formed between the two antinodes of said oscillatory movements of the at least one tube in the oscillation mode of the second order, in particular (nominally) located at a half tube length, is inside the reference cross-sectional area; - and / or wherein a main axis of inertia of the at least one tube located perpendicular to the direction of oscillation of the oscillatory movements of the tube in the oscillation mode of the second order is inside the reference cross-sectional area of the at least one tube.

7. The measuring system as claimed in one of the preceding claims, - wherein the drive offset corresponds to a distance between a centroid of an area (center point) of the drive cross-sectional area of the tube and a centroid of an area (center point) of the reference cross-sectional area of the at least one tube; and / or - wherein an effective line of the driving force runs perpendicular to a normal of a drive cross-sectional area of the tube; and / or - wherein an intersection line between two planes of symmetry which are orthogonal relative to one another of the at least one tube is inside the reference cross-sectional area; and / or - wherein a main axis of inertia of the at least one tube located perpendicular to the driving force is inside the reference cross-sectional area of the at least one tube; and / or - wherein the measuring system electronics are configured to supply the second useful current of the driver signal (e1) at least sometimes simultaneously with the first (useful) current, in particular in such a way that an amplitude of the first (useful) current is not set to be less than an amplitude of the second (useful) current and / or in such a way that an amplitude of the second (useful) current is set to more than 40%, in particular not less than 50%, of an amplitude of the first (useful) current; and / or - wherein the measuring system electronics are configured to set the second (alternating current) frequency as a function of the first (alternating current) frequency, in particular in such a way that the second (alternating current) frequency is within a frequency setting interval of which an upper interval limit and / or a lower interval limit and / or a center frequency correspond to a specified multiple of the first (alternating current) frequency, that is to say, in particular correspond to a multiple of the first (alternating current) frequency corresponding to more than 230% of the first (alternating current) frequency and / or less than 300% of the first (alternating current) frequency.

8. The measuring system as claimed in one of the preceding claims, wherein the measuring system electronics are configured, in order to run the (self-)diagnostics on the measuring system based on the at least one second useful signal components (s1N2; s2N2), in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2): - to detect whether and / or to what extent there is a disturbance of the measuring system, in particular a disturbance lessening an ability of the measuring system to function and / or bringing about a malfunctioning of the measuring system and / or reducing an integrity of at least one of the first and second oscillation measurement signals, or measured values obtained therefrom and / or provoking a measurement error of measured values obtained therefrom; and / or - to detect whether or to what extent the tube arrangement has changed compared to a reference state established in advance, that is to say, in particular is damaged, - and / or to detect whether and / or to what extent there is a disturbance of the measuring system due to one or more oscillation characteristics of the tube arrangement that has / have changed compared to a reference state established for this in advance, in particular due to damage to the tube arrangement, - and / or to detect whether and / or to what extent there is damage to the tube arrangement, in particular as a result of erosion on an inside of the tube wall facing toward the lumen and / or as a result of deposits forming on an inside of the tube wall facing toward the lumen, - and / or to detect whether and / or to what extent a measurement error is present due to damage to the measuring transducer, that is to say, in particular to the tube arrangement, when determining the measured values.

9. The measuring system as claimed in one of the preceding claims, - wherein the measuring system electronics are configured, in order to run (self-)diagnostics on the measuring system based on the second useful signal components (s1N2; s2N2), in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2), to detect whether a disturbance of the measuring system can be attributed to an, in particular irreversible, change in one or more flow characteristics of the tube arrangement, in particular due to a reduced flow cross-section of the tube arrangement, in particular as a result of a blockage of one or more of the tubes and / or as a result of a deposit on an inside of the tube wall of one or more of the tubes; and / or - wherein the measuring system electronics are configured, in order to run (self-)diagnostics on the measuring system based on the second useful signal components (s1N2; s2N2), in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2), to detect whether a disturbance of the measuring system can be attributed to an, in particular irreversible, change in one or more oscillation characteristics of the tube arrangement, in particular due to a reduced thickness of the tube wall of one or more of the tubes and / or due to a plastic deformation of one or more of the tubes and / or due to a deposit on an inside of the tube wall of one or more of the tubes and / or due to a crack in the tube wall of one or more of the tubes.

10. The measuring system as claimed in one of the preceding claims, - wherein the measuring system electronics are configured to determine a (signal) amplitude of a (modal) deflection of the first useful oscillations corresponding to the first useful signal components (s1N1), in particular a difference of the (signal) amplitudes of the first useful signal components (s1N1; s2N1), that is to say, in particular to determine deflection values representing the deflection of the first useful oscillations based on at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine a (signal) amplitude of a (modal) deflection of the first useful oscillations corresponding to the second useful signal components (s1N1), in particular a difference of the (signal) amplitudes of the second useful signal components (s1N1; s2N1), that is to say, in particular to determine deflection values representing the deflection of the second useful oscillations based on at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine a deflection ratio, x1 / x2, corresponding to a ratio of the (modal) deflection of the first useful oscillations and the (modal) deflection of the second useful oscillations, that is to say, in particular to determine deflection ratio values representing the deflection ratio, x1 / x2, based on at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine a (modal) damping, d1, of the first useful oscillations corresponding to a ratio of a (signal) amplitude of one of the first useful signal components (s1N1), in particular a total or a difference of the (signal) amplitudes of the first useful signal components (s1N1; s2N1), and a (signal) amplitude of the first (useful) current (eN1), that is to say, in particular to determine damping values representing the damping of the first useful oscillations based on the driver signal and at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine a (modal) damping, d2, of the second useful oscillations corresponding to a ratio of a (signal) amplitude of one of the second useful signal components (s1N2), in particular a total or a difference of the (signal) amplitudes of the second useful signal components (s1N2, s2N2), and a (signal) amplitude of the second (useful) current (eN2), that is to say, in particular to determine damping values representing the damping of the second useful oscillations based on the driver signal and at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine a damping ratio, d1 / d2, corresponding to a ratio of a (modal) damping, d1, of the first useful oscillations and a (modal) damping, d2, of the second useful oscillations, that is to say, in particular to determine damping ratio values representing the damping ratio, d1 / d2, based on the driver signal and / or at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine damping values representing a (modal) damping of the second useful oscillations based on the driver signal and at least one of the oscillation measurement signals, that is to say, in particular to compare one or more of the damping values with a reference value (damping reference value) ascertained for this in advance; and / or - wherein the measuring system electronics are configured to determine the resonant frequency f1 of the first oscillation mode of the at least one tube, that is to say, in particular to determine frequency values representing the resonant frequency f1 based on the driver signal and / or at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine the resonant frequency f2 of the second oscillation mode of the at least one tube, that is to say, in particular to determine frequency values representing the resonant frequency f2 based on the driver signal and / or at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine a resonant frequency ratio f1 / f2 corresponding to a ratio of the resonant frequency f1 of the first oscillation mode of the at least one tube and the resonant frequency f2 of the second oscillation mode of the at least one tube, that is to say, in particular to determine frequency ratio values representing the resonant frequency ratio f1 / f2 based on the first and second (alternating current) frequencies of the driver signal and / or based on the signal frequencies of the first and second useful signal components (s1N1, s1N2; s2N1, s2N2) of at least one of the oscillation measurement signals; and / or - wherein the measuring system electronics are configured to determine frequency values representing the resonant frequency f2 of the second oscillation mode of the at least one tube based on the driver signal and / or at least one of the oscillation measurement signals, that is to say, in particular to compare one or more of the frequency values with one or more reference values specified for this and / or to use several of the frequency values to determine a measure of dispersion for the resonant frequency f2 of second oscillation mode of the at least one tube; and / or - wherein the measuring system electronics are configured to determine frequency ratio values representing a ratio of the resonant frequency f1 of the first oscillation mode of the at least one tube and the resonant frequency f2 of the second oscillation mode of the at least one tube based on the driver signal and / or at least one of the oscillation measurement signals, that is to say, in particular to compare one or more of the frequency ratio values with one or more reference values specified for this and / or to use several of the frequency ratio values to determine a measure of dispersion for the resonant frequency ratio f1 / f2 of the at least one tube; and / or - wherein the measuring system electronics are configured to determine deflection ratio values representing a ratio of the deflections, x1, of the first useful oscillations and the deflections, x2, of the second useful oscillations based on at least one of the oscillation measurement signals, that is to say, in particular to compare one or more of the deflection ratio values with one or more reference values specified for this and / or to use several of the deflection ratio values to determine a measure of dispersion for the deflection ratio, x1 / x2, of the at least one tube; and / or - wherein the measuring system electronics are configured to supply the second (useful) current (eN2) with a specified (current) amplitude, that is to say, in particular in order to run the (self-)diagnostics on the measuring system, to compare on a recurring basis the (signal) amplitude of at least one of the second useful signal components (s1N2) with a reference value (amplitude reference value) dependent on the (signal) amplitude of the second (useful) current (eN2) and / or specified for this, or to detect whether or to what extent the (signal) amplitude differs from said reference value.

11. The measuring system as claimed in one of the preceding claims, wherein the measuring system electronics are configured to determine phase difference values representing a phase difference between the second useful signal components, that is to say a difference between a phase angle of the second useful signal component (s1N2) of the first oscillation measurement signal (s1) and a phase angle of the second useful signal component (s2N2) of the second oscillation measurement signal (s2) based on the oscillation measurement signals, that is to say, in particular to compare one or more of the phase difference values with a reference value (phase difference reference value) ascertained for this in advance and / or to use several of the phase difference values to determine a measure of dispersion for the phase difference between the second useful signal components of the at least one tube.

12. The measuring system as claimed in one of the preceding claims, - wherein the first useful signal components (s1N1; s2N1) of the first and second oscillation measurement signals follow a change in a mass flow of the measured substance conducted in the tube with a change in a phase difference between the first useful signal components, that is to say a difference between a phase angle of the first useful signal component (s1N1) of the first oscillation measurement signal (s1) and a phase angle of the first useful signal component (s2N1) of the second oscillation measurement signal (s2); - and wherein the measuring system electronics are configured to generate mass flow measured values representing the mass flow based on the phase difference between the first useful signal components (s1N1; s2N1).

13. The measuring system as claimed in claims 11 and 12, wherein the measuring system electronics are configured, in particular in order to run the (self-)diagnostics on the measuring system, to check or calibrate a (mass flow to phase difference) characteristic curve function of the measuring transducer, according to which the phase difference between the first useful signal components depends on the mass flow, and / or to check or calibrate a (mass flow to measured value) characteristic curve function of the measuring system, according to which mass flow measured values ascertained based on the phase difference between the first useful signal components depend on the mass flow, based on the second useful signal components (s1N2; s2N2) of at least one of the oscillation measurement signals, in particular based on a phase angle of at least one of the second useful signal component and / or based on a phase difference between the second useful signal components.

14. The measuring system as claimed in the preceding claim, wherein the measuring system electronics are configured, in particular in order to run the (self-)diagnostics on the measuring system, to check the (mass flow to phase difference) characteristic curve function of the measuring transducer, in particular a (scale) zero point of said characteristic curve function, based on a phase difference between the second useful signal components, that is to say a difference between a phase angle of the second useful signal component (s1N2) of the first oscillation measurement signal (s1) and a phase angle of the second useful signal component (s2N2) of the second oscillation measurement signal (s2), that is to say, in particular to detect whether or to what extent there is a drift of the characteristic curve function.

15. The measuring system as claimed in the preceding claim, wherein the measuring system electronics are configured, in particular in order to run the (self-)diagnostics on the measuring system, to check a (scale) zero point of the (mass flow to phase difference) characteristic curve function of the measuring transducer, which corresponds to a phase difference between the first useful signal components measured when the measured substance is still or a mass flow measured value ascertained when the measured substance is still, and / or a (measuring) sensitivity of the measuring system, which corresponds to a change in the phase difference between the first useful signal components related to a change in the mass flow, that is to say, in particular to detect whether or to what extent the (scale) zero point has changed irreversibly.

16. The measuring system as claimed in one of the preceding claims, - wherein the measuring system electronics are configured to follow a change in a density of the measured substance conducted in the tube with a change in the first (alternating current) frequency of the driver signal, - and wherein the measuring system electronics are configured to generate density measured values representing the density based on the first (alternating current) frequency of the driver signal and / or based on the signal frequency of the first useful signal component of at least one of the oscillation signals (s1N1; s2N1).

17. The measuring system as claimed in one of the preceding claims, wherein the measuring system electronics are configured, in particular in order to run the (self-)diagnostics on the measuring system, to calculate one or more characterizing number values for at least one measuring system characterizing number (MK1) which characterizes an operating state of the measuring system, based on the second useful signal component (s1N2; s2N2) of at least one of the oscillation measurement signals, in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2), in particular in such a way that said measuring system characterizing number depends on one or more parameters of a system function of the measuring system mediating between the second useful current components of the driver signal (e1) and the second useful signal components (s1N2; s2N2) of the at least one oscillation measurement signal.

18. The measuring system as claimed in the preceding claim, wherein the measuring system electronics (20) are configured, in order to run the (self-)diagnostics on the measuring system, to compare one or more characterizing number values for the measuring system characterizing number in each case with one or more reference values ascertained for the measuring system characterizing number, in particular by the manufacturer of the measuring system and / or during manufacture and / or a start-up of the measuring system and / or as a function of the driver signal, in particular one or more reference values representing a lessened functionality of the measuring transducer and / or one or more reference values representing a malfunctioning of the measuring transducer and / or one or more reference values representing a defective measuring transducer, in particular to evaluate and / or to quantify a deviation of one or more of the characterizing number values from one or more of the reference values.

19. The measuring system as claimed in the preceding claim, wherein the measuring system electronics (20) are configured to ascertain whether one or more characterizing number values for the measuring system characterizing number (MK1) are greater than the at least one reference value for the measuring system characterizing number, that is to say, in particular if one or more characterizing number values for the measuring system characterizing number are greater than one or more reference values representing a lessened functionality of the measuring transducer and / or greater than one or more reference values representing a malfunctioning of the measuring transducer and / or greater than one or more reference values representing a no longer intact measuring transducer, to output a notification representing this, in particular declared as a (disturbance) alarm.

20. The measuring system as claimed in one of the preceding claims, wherein the measuring system electronics (20) have a non-volatile electronic data memory (EEPROM) that is configured to provide digital data, in particular even when there is no operating voltage, that is to say, in particular to store one or more reference values ascertained in advance for the measuring system characterizing number.

21. The measuring system as claimed in the preceding claim in conjunction with one of claims 17 to 19, wherein there are stored in the electronic memory one or more reference values for the measuring system characterizing number, in particular ascertained in advance by the manufacturer of the measuring system and / or during manufacture of the measuring system and / or during operation of the measuring system, that is to say, in particular, one or more reference values representing a lessened functionality of the measuring transducer and / or that is to say one or more reference values representing a malfunctioning of the measuring transducer.

22. The measuring system as claimed in the preceding claim, wherein the measuring system electronics (20) are configured to compare one or more characterizing number values for the measuring system characterizing number in each case with one or more reference values for the measuring system characterizing number stored in the memory.

23. The measuring system as claimed in one of the preceding claims, wherein the measuring system electronics are configured to supply the driver signal (e1) with the second (useful) current (eN2) during a test interval, in particular which lasts for more than 10 ms and / or is temporary and / or is restarted repeatedly, in particular in such a way that the second (useful) current (eN2) is non-volatile or stationary, that is to say has a (mostly) constant amplitude that is not zero for two or more oscillation periods and / or for a time period of more than 10 ms (milliseconds).

24. The measuring system as claimed in the preceding claim, - wherein the measuring system electronics are configured, during the test interval, to determine measured values representing the at least one measured variable based on the second useful signal components (s1N2; s2N2), in particular based on their (signal) frequency and / or based on a (signal) amplitude of at least one of the second useful signal components (s1N2) and / or based on a phase angle of at least one of the second useful signal components (s1N2); and / or - wherein each test interval lasts for more than 100 ms (milliseconds), in particular not less than 1 s (second); and / or - wherein the measuring system electronics are configured to start and / or to end the test interval automatically, in particular in a time-controlled manner, in particular on a recurring basis; and / or - wherein the measuring system electronics are configured to receive and execute one or more commands which start the test interval.

25. The measuring system as claimed in one of the preceding claims, - wherein the exciter arrangement, with the exception of the oscillation exciter (31), does not have any other oscillation exciters that are connected to the tube; and / or - wherein the oscillation exciter (31) is positioned and aligned in such a way that the drive offset is less than 0.5 mm, that is to say, in particular is zero, or in such a way that the centroid of an area of the drive cross-sectional area of the tube corresponds to the drive reference point or coincides with it; and / or - wherein both of the oscillation modes of the first and of the second order of the tube has in each case a first node located in the first tube end of the at least one tube and a second node located in the second tube end of the at least one tube; and / or - wherein the tube is curved in sections, in particular is in the shape of an arc and / or a V, in particular in such a way that the tube has a central crown segment and / or in such a way that precisely one main axis of inertia of the at least one tube is inside the reference cross-sectional area of the at least one tube; and / or - wherein the tube is straight in sections, in particular over the entire tube length, in particular in such a way that a center of mass is inside the reference cross-sectional area of the at least one tube; and / or - wherein the oscillation exciter (31) is formed by a moving coil, in particular one having an air coil and an anchor; and / or - wherein both of the first and second oscillation sensors are formed in each case by a plunger coil, in particular one with an air coil and an anchor.

26. The measuring system as claimed in one of the preceding claims, wherein the tube arrangement has at least one second tube (112), in particular curved at least in sections and / or straight at least in sections and / or identical in design to the first tube and / or parallel to the first tube at least in sections.

27. The measuring system as claimed in the preceding claim, - wherein the second tube extends from a first tube end to a second tube end with a tube length and has a lumen surrounded by an, in particular metal, tube wall extending from the first tube end to the second tube end, and wherein the second tube is configured to have the measured substance flow through it, at least in a flow direction going from the first tube end to the second tube end, in particular at the same time as the first tube, and during that to be caused to oscillate; and / or - wherein the oscillation exciter (31) is partially mechanically connected to the first tube and also partially mechanically connected to the second tube; and / or - wherein the oscillation exciter (31) is configured to act differentially on the first and second tubes, in particular in such a way that the first and second tubes simultaneously execute forced mechanical oscillations in opposite directions at the same frequency; and / or - wherein the oscillation exciter (31) is configured to convert electrical power of a time-variable electrical current into mechanical power in such a way that a time-variable driving force acts on the second tube at a drive point formed by means of the oscillation exciter on the second tube mechanically connected to it, in particular at the same time as and / or in the opposite direction to the driving force acting on the first tube at the drive point formed by means of the oscillation exciter on the first tube mechanically connected to it; and / or - wherein the oscillation exciter (31) is configured to convert electrical power supplied by means of the electrical driver signal (e1) simultaneously into forced mechanical oscillations of the first and second tubes, in particular in such a way that the first and second tubes simultaneously execute forced mechanical oscillations with the first useful frequency and / or with the second useful frequency.

28. The measuring system as claimed in one of claims 26 to 27, wherein a number of oscillation modes (natural modes) each with an associated resonant frequency are inherent to the second tube, in which the second tube can execute or executes oscillatory movements having in each case one or more antinodes and in each case two or more nodes, in particular in such a way that oscillatory movements of the second tube in the oscillation mode of the second order (f2-Mode) are in the opposite direction to, in particular mirror-inverted to, the oscillatory movements of the first tube in the oscillation mode of the second order (f2-Mode) and / or in such a way that oscillatory movements of the second tube in the oscillation mode of the first order (f1-Mode) are in the opposite direction to, in particular mirror-inverted, to the oscillatory movements of the first tube in the oscillation mode of the first order, in particular in such a way that a resonant frequency of the oscillation mode of the first order of the first tube is the same as a resonant frequency of the oscillation mode of the first order (f1-Mode) of the second tube and in such a way that a resonant frequency of the oscillation mode of the second order of the first tube is the same as a resonant frequency of the oscillation mode of the second order of the second tube.