Vibronic measuring system

Abstract

The invention relates to a measuring system comprising: a measuring transducer having at least one measuring tube (10) for guiding an at least intermittently flowing fluid measurement substance, an exciter arrangement (41), and a sensor arrangement (51, 52); and an electronic transformer circuit (US) that is electrically coupled both to the exciter arrangement and to the sensor arrangement and has measurement and control electronics (DSV) and drive electronics (Exc) connected thereto and / or controlled thereby. The exciter arrangement is electrically connected to the drive electronics (Exc) and is also designed to convert fed electrical power into mechanical power that causes forced mechanical oscillations of the at least one measuring tube, and the sensor arrangement is designed to detect mechanical oscillations of the at least one measuring tube and to provide corresponding oscillation measuring signals (s1, s2) which follow a change in a mass flow rate of the measurement substance guided in the measuring tube with a change in a (phase) difference between a phase angle of the measuring signal (s1) and a phase angle of the measuring signal (s2). The drive electronics in turn is designed, in a manner controlled by the measurement and control electronics, to generate, in an operating mode (I), an electric driver signal (e1) having a first signal amplitude and a first signal frequency and, in an operating mode (II), an electric driver signal (e2) having a second signal amplitude, that is different from the first signal amplitude, and a second signal frequency, and thus in each case to feed electric power into the exciter arrangement in such a way that the at least one measuring tube, at least during a first measurement interval, performs forced mechanical oscillations with a useful amplitude and frequency predefined by the driver signal (e1) or, at least during a second measurement interval, performs forced mechanical oscillations with a useful amplitude and frequency predefined by the driver signal (e2). In the measuring system according to the invention, the measurement and control electronics (DSV) are also designed to determine phase error measurement values (XErr) that represent deviations of phase angles or phase differences on the basis of measurement signals (s1, s2) provided during the first and second measurement intervals.

Description

[0001] Vibronic measuring system

[0002] The invention relates to a vibronic measuring system with a vibration-type measuring transducer and an electronic converter circuit connected thereto.

[0003] In industrial measurement technology, vibronic measuring systems are often used for the highly accurate determination of a mass flow rate (mass flow) of a medium flowing in a process line, such as a pipeline, such as a liquid, a gas, or a dispersion. These systems are often formed by a converter circuit, usually formed by at least one microprocessor, and a vibration-type measuring transducer electrically connected to the converter circuit and through which the medium to be measured flows during operation. Examples of such vibronic measuring systems, for example, designed as Coriolis mass flow meters and / or density and / or viscosity meters, include:in EP-A 816 807, US-A 2002 / 0033043, US-A 2006 / 0096390, US-A 2007 / 0062309, US-A 2007 / 0119264, US-A 2008 / 0011101, US-A 2008 / 0047362, US-A 2008 / 0190195, US-A 2008 / 0250871, the.

[0004] US-A 2010 / 0005887, US-A 2010 / 0011882, US-A 2010 / 0257943, US-A 2011 / 0161017, US-A 2011 / 0178738, US-A 2011 / 0219872, US-A 2011 / 0265580,

[0005] US-A 2011 / 0271756, US-A 2012 / 0123705, US-A 2013 / 0042700, US-A 2016 / 0313162, US-A 2017 / 0261474, US-A 2020 / 0408581, US-A 44 91 009, US-A 47 56 198, US-A 47 77 833, US-A 48 01 897, US-A 48 76 898, US-A 49 96 871, the

[0006] US-A 50 09 109, US-A 52 87 754, US-A 52 91 792, US-A 53 49 872,

[0007] US-A 57 05 754, US-A 57 96 010, US-A 57 96 011, US-A 58 04 742,

[0008] US-A 58 31 178, US-A 59 45 609, US-A 59 65 824, US-A 60 06 609,

[0009] US-A 60 92 429, US-B 62 23 605, US-B 63 11 136, US-B 64 77 901 ,

[0010] US-B 65 05 518, US-B 65 13 393, US-B 66 51 513, US-B 66 66 098,

[0011] US-B 67 11 958, US-B 68 40 109, US-B 69 20 798, US-B 70 17 424,

[0012] US-B 70 40 181 , US-B 70 77 014, US-B 72 00 503, US-B 72 16 549,

[0013] US-B 72 96 484, US-B 73 25 462, US-B 73 60 451, US-B 77 92 646,

[0014] US-B 79 54 388, US-B 83 33 120, US-B 86 95 436, WO-A 00 / 19175, WO-A 00 / 34748, WO-A 01 / 02816, WO-A 01 / 71291, WO-A 02 / 060805,

[0015] WO-A 2005 / 093381, WO-A 2007 / 043996, WO-A 2008 / 013545, WO-A 2008 / 059262, WO-A 2010 / 099276, WO-A 2013 / 092104, WO-A 2014 / 151829, WO-A 2016 / 058745, WO-A 2017 / 069749, WO-A 2017 / 123214, WO-A 2017 / 143579, WO-A 85 / 05677, WO-A 88 / 02853, WO-A 89 / 00679, WO-A 94 / 21999, WO-A 95 / 03528, WO-A 95 / 16897, WO-A 95 / 29385, WO-A 98 / 02725, WO-A 99 / 40394 or international patent application PCT / EP2021 / 083169.

[0016] The measuring transducer of each of the measuring systems shown therein comprises at least one measuring tube that is at least partially straight and / or at least partially curved, e.g., U-, V-, S-, Z-, or Q-shaped, with a lumen surrounded by a tube wall for conveying the medium. The at least one measuring tube of such a measuring transducer is designed to convey medium in the lumen and, during this time, to be vibrated, in particular in such a way that it executes useful oscillations, namely mechanical oscillations around a rest position with a useful frequency that is also determined by the density of the medium and can therefore be used as a measure of the density.In conventional measuring systems of the type in question, not least Coriolis mass flowmeters, bending vibrations at a natural resonance frequency typically serve as useful vibrations, for example, those bending vibrations that correspond to a natural bending vibration fundamental mode inherent in the measuring transducer, in which the vibrations of the measuring tube are such resonant vibrations that exhibit exactly one antinode. In the case of a measuring tube that is curved at least in sections, the useful vibrations are also typically designed such that the measuring tube oscillates around an imaginary vibration axis that imaginarily connects an inlet and an outlet end of the measuring tube, like a cantilever clamped at one end. In contrast, in measuring transducers with a straight measuring tube, the useful vibrations are usually bending vibrations in a single imaginary vibration plane.It is also known to occasionally excite the at least one measuring tube to temporary, forced oscillations outside of resonance, for example for the purpose of carrying out recurring checks of the measuring transducer during operation of the measuring system, or occasionally to enable free, damped oscillations of the at least one measuring tube and to evaluate these oscillations in each case, for example in order to detect, as also described in the aforementioned EP-A 816 807, US-A 2011 / 0178738 or US-A 2012 / 0123705, any damage to the at least one measuring tube as early as possible, which could cause an undesirable reduction in the measuring accuracy and / or the operational reliability of the respective measuring system.

[0017] In the case of transducers with two measuring tubes, these are usually integrated into the respective process line via a manifold extending between the measuring tubes and an inlet-side connection flange, and via a manifold extending between the measuring tubes and an outlet-side connection flange. In the case of transducers with a single measuring tube, the latter usually communicates with the process line via a connecting pipe opening into the inlet and a connecting pipe opening into the outlet.Furthermore, measuring transducers with a single measuring tube each comprise at least one single-piece or multi-piece counteroscillator, for example, tubular, box-shaped, or plate-shaped, which is coupled to the measuring tube on the inlet side, forming a first coupling zone, and which is coupled to the measuring tube on the outlet side, forming a second coupling zone, and which, during operation, is essentially stationary or oscillates opposite to the measuring tube. The inner part of the measuring transducer, formed by the measuring tube and counteroscillator, is usually held in a protective measuring transducer housing solely by means of the two connecting tubes through which the measuring tube communicates with the process line during operation, particularly in a manner that allows oscillations of the inner part relative to the measuring transducer housing.In the measuring transducers 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 / 02 816 or WO-A 99 / 40 394 with a single, essentially straight measuring tube, the latter and the counteroscillator are aligned essentially coaxially with one another, as is quite common in conventional measuring transducers, in that the counteroscillator is designed as an essentially straight hollow cylinder and is arranged in the measuring transducer such that the measuring tube is at least partially encased by the counteroscillator. The materials used for such counteroscillators, especially when titanium, tantalum or zirconium are used for the measuring tube, are usually comparatively inexpensive types of steel, such as structural steel or free-cutting steel.

[0018] In order to actively excite or maintain vibrations of the at least one measuring tube, not least also the aforementioned useful vibrations, measuring transducers of the vibration type further comprise an electromechanical vibration exciter which, during operation, acts differentially on the at least one measuring tube and the possibly present counter-oscillator or the possibly present other measuring tube.The vibration exciter, which is electrically connected to the aforementioned converter circuit by means of a pair of electrical connecting lines, for example in the form of connecting wires and / or conductor tracks of a flexible printed circuit board, serves in particular to convert an electrical excitation power fed in by means of the same drive signal into a driving force acting on the at least one measuring tube at an application point formed by the vibration exciter by means of an electrical drive signal provided in the converter circuit and correspondingly conditioned, namely at least adapted to changing vibration properties of the at least one measuring tube. The drive electronics are also particularly designed to adjust the drive signal by means of internal control such that it has a signal frequency corresponding to the useful frequency to be excited, which occasionally also changes over time.The drive signal can, for example, occasionally be switched off during operation of the respective measuring system, for example, to enable the aforementioned free damped oscillations of the at least one measuring tube or, for example, as proposed in the aforementioned WO-A 2017 / 143579, to protect the drive electronics from overload. Vibration exciters of commercially available vibration-type measuring transducers or vibronic measuring systems of the type in question are typically constructed in the manner of an oscillating coil operating according to the electrodynamic principle, namely by means of a coil—in the case of measuring transducers with a measuring tube and a counteroscillator coupled to it, usually fixed to the latter—and a permanent magnet interacting with the at least one coil, serving as an armature and correspondingly fixed to the measuring tube to be moved.The permanent magnet and the coil are usually aligned so that they run essentially coaxially with one another. In addition, in conventional measuring transducers the vibration exciter is usually designed and positioned so that it acts essentially centrally on the at least one measuring tube. As an alternative to a vibration exciter that acts more centrally and directly on the measuring tube, it is possible, as in the aforementioned US-A 60 92 429, for example, to use two vibration exciters that are not fixed in the center of the measuring tube but rather on the inlet or outlet side to actively excite mechanical vibrations of the at least one measuring tube, or, as proposed in US-B 62 23 605 or US-A 55 31 126, for example, exciter arrangements formed by means of a vibration exciter acting between the counteroscillator, if present, and the measuring transducer housing can be used.

[0019] Due to the useful vibrations of the at least one measuring tube, Coriolis forces are known to be induced in the flowing medium, which are dependent on the instantaneous mass flow rate – not least in the case where the useful vibrations of the at least one measuring tube are bending vibrations. These, in turn, can cause Coriolis vibrations with a useful frequency that are dependent on the mass flow rate and superimposed on the useful vibrations. This allows a transit time or phase difference, which is also dependent on the mass flow rate and can therefore also be used as a measure for mass flow measurement, to be detected between the inlet-side and outlet-side vibrational movements of the at least one measuring tube that performs the useful vibrations and is simultaneously flowed through by the medium.In the case of a measuring tube which is curved at least in sections and in which a vibration mode is selected for the useful vibrations in which the measuring tube is allowed to oscillate in the manner of a cantilever clamped at one end, the resulting Coriolis vibrations correspond, for example, to that bending vibration mode - occasionally also referred to as twist mode - in which the measuring tube executes torsional vibrations about an imaginary torsional vibration axis oriented perpendicular to the aforementioned imaginary vibration axis, whereas in the case of a straight measuring tube, the useful vibrations of which are designed as bending vibrations in a single imaginary vibration plane, the Coriolis vibrations are, for example, bending vibrations which are essentially coplanar with the useful vibrations.

[0020] In order to detect both inlet-side and outlet-side vibrational movements of the at least one measuring tube, not least also those corresponding to the useful vibrations, and to generate at least two electrical vibration measurement signals influenced by the mass flow rate to be measured, measuring transducers of the type in question further comprise two or more vibration sensors spaced apart from one another along the measuring tube, for example each electrically connected to one another in the aforementioned converter circuit by means of its own pair of electrical connecting lines.Each of the vibration sensors is configured to convert the aforementioned vibration movements into a vibration measurement signal representing them, which contains a useful signal component, namely a (spectral) signal component with a signal frequency corresponding to the useful frequency, and to provide this vibration measurement signal to the converter circuit, for example, namely a measuring and control electronics unit of the converter circuit formed by at least one microprocessor, for further, possibly also digital, processing. Furthermore, the at least two vibration sensors are designed and arranged such that the vibration measurement signals generated thereby not only each have a useful signal component, as already mentioned, but also that a transit time or (measurement) phase difference, dependent on the mass flow rate, can be measured between the useful signal components of both vibration measurement signals.Based on this phase difference, the converter circuit or its measuring and control electronics repeatedly determines mass flow rate measured values ​​representing the mass flow rate. In addition to measuring the mass flow rate, the density and / or viscosity of the medium can also be measured—for example, based on the useful frequency and / or the electrical excitation power required to excite or maintain the useful oscillations, or the damping of the useful oscillations determined from this power—and output by the converter circuit together with the measured mass flow rate in the form of qualified measured values.

[0021] Investigations on conventional measuring systems, each designed as a Coriolis mass flow meter, have shown that, despite a constant mass flow rate, there is occasionally a significant phase error between the above-mentioned useful signal components of both vibration measurement signals, for example such that a temporal change in the phase difference can be observed which can no longer be neglected, or that the phase difference established between the same useful signal components occasionally has a fleeting, but nevertheless non-negligible, interference component which is not dependent on the mass flow rate; this applies, for example, in applications with media which change rapidly over time in terms of density and / or viscosity or composition, in applications with inhomogeneous media, namely media which have two or more different phases, in applications with time-dependent ora medium that is allowed to flow intermittently or in applications where the medium is occasionally changed during the measurement, such as in filling plants or in refueling devices. As also discussed in the aforementioned US-A 2020 / 0408581, WO-A 2017 / 069749 or US-B 79 54 388, the aforementioned phase error can, for example, result from an electromagnetic coupling of the oscillation signals and the driver signal (crosstalk), for example within the converter circuit and / or within the measuring transducer. In addition, such a phase error can, among other things, also be due to the fact that the useful oscillations actively excited by means of the oscillation exciter are asymmetrically excited or damped with respect to an imaginary line of action of the driving force driving the useful oscillations, in such a way that the excited useful oscillations - in particularEven in the case of transducers with a single vibration exciter acting centrally on at least one measuring tube, they can exhibit a disturbance component comparable to Coriolis vibrations.

[0022] In order to reduce or eliminate phase errors caused by electromagnetic coupling, the drive electronics of the measuring system shown in US-A 2020 / 0408581 are, among other things, also designed, controlled by the measuring and control electronics, to operate optionally in a first operating mode which effects the aforementioned active excitation of the useful oscillations by means of the electrical drive signal and subsequently temporarily in a second operating mode which does not supply an electrical drive signal, in such a way that at least one measuring tube (with drive electronics operating in the first operating mode) executes forced oscillations at least during a first measuring interval and (with drive electronics operating in the second operating mode) executes free damped oscillations at least during a second measuring interval.In addition, the measuring and control electronics of the measuring system shown in US-A 2020 / 0408581 are designed to determine the mass flow measured value based on the first and second vibration measuring signals received at least during a second measuring interval and no longer containing the aforementioned interference component, or on their respective phase difference which no longer contains the phase error.

[0023] One disadvantage of such a determination of mass flow measured values ​​is that the required phase angles or phase differences must be determined based on the vibration signals of the decaying free vibrations, which are actually less suitable with regard to their (signal-to-noise ratio) or their signal-to-noise ratio (SN).

[0024] Based on the aforementioned prior art, it is an object of the invention to improve vibronic measuring systems of the aforementioned type in such a way that the time-varying phase error during operation can be repeatedly determined at least approximately, in particular quantified, and / or taken into account accordingly when determining mass flow measured values.

[0025] To achieve the object, the invention consists in a vibronic measuring system, for example a Coriolis mass flow meter, which measuring system comprises: a measuring transducer with at least one measuring tube, with an excitation arrangement and with a sensor arrangement;

[0026] • and an electronic converter circuit which is electrically coupled to both the excitation arrangement and the sensor arrangement, for example formed by means of at least one microprocessor and / or programmable, with a measuring and control electronics and with a drive electronics which is connected to the measuring and control electronics, for example electrically, and / or controlled by the measuring and control electronics;

[0027] • wherein the measuring tube is designed to carry a fluid measuring substance, for example a gas, a liquid or a dispersion, which flows at least temporarily and is allowed to vibrate during this time;

[0028] • wherein the excitation arrangement is designed to convert electrical power fed thereto into mechanical power causing forced mechanical oscillations of the at least one measuring tube;

[0029] • wherein the sensor arrangement is configured to detect mechanical vibrations of the at least one measuring tube and to provide a first vibration measurement signal representing at least partially vibration movements of the at least one measuring tube and at least one second vibration measurement signal representing at least partially vibration movements of the at least one measuring tube, for example in such a way that the same first and second vibration measurement signals follow a change in a mass flow rate of the medium being conveyed in the measuring tube with a change in a phase difference, namely a change in a difference between a phase angle of the first vibration measurement signal and a phase angle of the second vibration measurement signal;

[0030] • wherein the drive electronics is set up, in a first operating mode (I), to generate a first electrical drive signal with a first signal frequency, in particular a constant and / or an instantaneous resonance frequency corresponding to a natural oscillation mode inherent in the measuring transducer, and a first signal amplitude, in particular a constant.namely a first (signal) voltage amplitude and / or a first (signal) current amplitude, and thus to feed electrical power into the excitation arrangement, such that the at least one measuring tube carries out first useful oscillations, namely forced mechanical oscillations with a first useful frequency, namely an oscillation frequency corresponding to the first signal frequency (of the first electrical drive signal) and with a first useful amplitude, namely an oscillation amplitude corresponding to the first signal amplitude (of the first electrical drive signal), and the first oscillation measurement signal has a first phase angle and the second oscillation measurement signal has a second phase angle;.

[0031] • and wherein the drive electronics is set up, in a second operating mode, to generate a second electrical drive signal with a second signal frequency, in particular a constant and / or an instantaneous resonance frequency of a natural oscillation mode inherent in the measuring transducer and / or corresponding to the first signal frequency, and a second signal amplitude, in particular a constant, deviating from the first signal amplitude, in particular by not less than 10% of the first signal amplitude, in particularnamely a second (signal) voltage amplitude and / or a second (signal) current amplitude, and thus to feed electrical power into the excitation arrangement, such that the at least one measuring tube carries out second useful oscillations, namely forced mechanical oscillations with a second useful frequency, namely an oscillation frequency corresponding to the second signal frequency (of the second electrical drive signal) and with a second useful amplitude, namely an oscillation amplitude corresponding to the second signal amplitude (of the second electrical drive signal), and the first oscillation measurement signal has a third phase angle and the second oscillation measurement signal has a fourth phase angle;.

[0032] • wherein the measuring and control electronics are set up to control the drive electronics in such a way that the drive electronics operate in the first operating mode at least temporarily, in particular temporarily and / or for longer than a reciprocal of the first useful frequency and / or for more than 10 ms in each case, and at least one measuring tube (with drive electronics operating in the first operating mode) carries out first (useful) oscillations at least during a first measuring interval, in particular corresponding to more than a reciprocal of the first useful frequency and / or lasting longer than 10 ms, and that the drive electronics operate in the second operating mode at least temporarily, in particular temporarily and / or for longer than a reciprocal of the second useful frequency and / or for more than 10 ms in each case and / or intermittently to the first operating mode, and at least one measuring tube (with drive electronics operating in the second operating mode) carries out first (useful) oscillations at least during a first measuring interval, in particularperforms second (useful) oscillations corresponding to more than one reciprocal of the second useful frequency and / or lasting longer than 10 ms;

[0033] • and wherein the measuring and control electronics are set up to receive and evaluate the first and second vibration measurement signals, namely to determine one or more, for example, digital, mass flow measurement values, namely the mass flow rate (of the medium carried in the at least one measuring tube) based on at least one first and second vibration measurement signals received during one or more first measuring intervals, and one or more, for example, digital, phase error measurement values, namely one, for example, absolute or relative, based on one or more first and second vibration measurement signals received during one or more first and second measuring intervals,(Measurement) deviation of one or more first phase angles (of the first vibration measurement signal received during one or more first measurement intervals) from one or more third phase angles (of the first vibration measurement signal received during one or more second measurement intervals) and / or a, for example absolute or relative, (measurement) deviation of one or more second phase angles (of the second vibration measurement signal received during one or more first measurement intervals) from one or more fourth phase angles (of the second vibration measurement signal received during one or more second measurement intervals) and / or a, for example absolute or relative,To determine the (measurement) deviation of one or more first phase differences of the first and second vibration measurement signals received during one or more first measurement intervals from one or more second phase differences of the first and second vibration measurement signals received during one or more second measurement intervals.

[0034] Furthermore, the invention also consists in using such a measuring system for measuring and / or monitoring a fluid medium flowing at least temporarily in a pipeline, for example at least temporarily inhomogeneous and / or at least temporarily 2- or multi-phase, for example a gas, a liquid or a dispersion.

[0035] According to a first embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are set up to determine one or more mass flow measured values ​​using one or more phase error measured values, for example in such a way that the measuring and control electronics are set up to determine at least one correction value which is useful for reducing or compensating a phase error contained in the first phase differences (of the first and second vibration measurement signals received during one or more first measuring intervals) using one or more phase error measured values ​​and to take this into account when determining the mass flow measured values ​​or to calculate the mass flow measured values ​​using the at least one correction value.

[0036] According to a second embodiment of the measuring system of the invention, it is further provided that the

[0037] Measuring and control electronics is set up to calculate, using a plurality of phase error measured values, one or more key figure values ​​for at least one statistical (measurement system) key figure, for example a position measure or a dispersion measure of a measurement value ensemble comprising a plurality of phase error measured values, for example in such a way that one or more key figure values ​​quantify a (central) tendency of the phase error measured values ​​and / or that one or more key figure values ​​quantify a dispersion parameter of the phase error measured values.

[0038] According to a third embodiment of the measuring system of the invention, it is further provided that one or more phase error measured values ​​represent, for example quantify, a (central) tendency, for example a mode, a median, an (empirical) mean value, of the (measurement) deviation of one or more first phase angles from one or more third phase angles.

[0039] According to a fourth embodiment of the measuring system of the invention, it is further provided that one or more phase error measured values ​​represent, for example, quantify, a (central) tendency, for example a mode, a median, an (empirical) mean value, of the (measurement) deviation of one or more second phase angles from one or more fourth phase angles.

[0040] According to a fifth embodiment of the measuring system of the invention, it is further provided that one or more phase error measured values ​​represent, for example, quantify, a (central) tendency, for example a mode, a median, an (empirical) mean value, of the (measurement) deviation of one or more first phase differences from one or more second phase differences.

[0041] According to a sixth embodiment of the measuring system of the invention, it is further provided that one or more phase error measured values ​​represent, for example, quantify, a scatter parameter, for example an (empirical) variance, an (empirical) standard deviation or a range, of the (measurement) deviation of one or more first phase angles from one or more third phase angles.

[0042] According to a seventh embodiment of the measuring system of the invention, it is further provided that one or more phase error measured values ​​represent, for example, quantify, a scatter parameter, for example an (empirical) variance, an (empirical) standard deviation or a range, of the (measurement) deviation of one or more second phase angles from one or more fourth phase angles.

[0043] According to an eighth embodiment of the measuring system of the invention, it is further provided that one or more phase error measured values ​​represent, for example, quantify, a scatter parameter, for example an (empirical) variance, an (empirical) standard deviation or a range, of the (measurement) deviation of one or more first phase differences from one or more second phase differences.

[0044] According to a ninth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine a deviation of one or more phase error measured values ​​from at least one phase error reference value, for example representing a phase error measured value determined under reference conditions and / or during a (re-)calibration of the measuring system.

[0045] According to a tenth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are set up to compare one or more phase error measured values ​​with at least one phase error threshold value, for example one that is specific to the measuring system and / or represents a maximum permissible phase error measured value or a fault in the measuring system and / or the measured substance, for example to output a (fault) message if one or more phase error measured values ​​have exceeded at least one phase error threshold value.

[0046] According to an eleventh embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine one or more mass flow measured values ​​based also on first and second vibration measuring signals received during one or more second measuring intervals.

[0047] According to a twelfth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine, based on first vibration measurement signals received during one or more first measurement intervals, one or more (first) phase angle measurement values, for example digital, representing the first phase angle (of the first vibration measurement signal received during one or more first measurement intervals).

[0048] According to a thirteenth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine, based on second vibration measurement signals received during one or more first measurement intervals, one or more (second) phase angle measurement values, for example digital, representing the second phase angle (of the second vibration measurement signal received during one or more first measurement intervals).

[0049] According to a fourteenth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are set up, based on first vibration measurement signals received during one or more second measuring intervals, to generate one or more, for example digital, signals representing the third phase angle (of the first vibration measurement signal received during one or more second measuring intervals).

[0050] (third) phase angle measurements.

[0051] According to a fifteenth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine, based on second vibration measurement signals received during one or more second measurement intervals, one or more (fourth) phase angle measurement values, for example digital, representing the fourth phase angle (of the second vibration measurement signal received during one or more second measurement intervals).

[0052] According to a sixteenth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine, based on first and second vibration measurement signals received during one or more first measurement intervals, one or more, for example, digital, (first) phase difference measurement values, namely measurement values ​​representing the (first) phase difference of the first and second vibration measurement signals (received during one or more first measurement intervals). Further developing this embodiment of the invention, it is further provided that the measuring and control electronics are configured to determine one or more mass flow measurement values ​​using one or more first phase difference measurement values.

[0053] According to a seventeenth embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are configured to determine one or more, for example, digital, (second) phase difference measured values, namely the measured values ​​representing the (second) phase difference of the first and second vibration measurement signals (received during one or more second measurement intervals), based on the first and second vibration measurement signals received during one or more second measurement intervals. Further developing this embodiment of the invention, it is further provided that the measuring and control electronics are configured to determine one or more mass flow measured values ​​using one or more second phase difference measured values.

[0054] According to an eighteenth embodiment of the measuring system of the invention, it is further provided that the converter circuit, for example its measuring and control electronics, is set up, for example when the drive electronics are operating in the first operating mode or before the drive electronics are switched from the first to the second operating mode, to generate a message, for example by means of a control signal and / or to transmit it to a display element of the measuring system, which message indicates or causes the mass flow of the medium being conveyed in the at least one measuring tube to be set to a constant, for example zero, (mass flow) value.According to a nineteenth embodiment of the measuring system of the invention, it is further provided that the converter circuit, for example namely its measuring and control electronics, is set up to effect a, for example multiple, change of the drive electronics from the first operating mode to the second operating mode (and vice versa) automatically, for example time and / or event controlled, and / or based on a control signal applied to the converter circuit, for example triggered by a (start) command transmitted thereby and / or a message transmitted thereby that the mass flow of the medium being measured in the at least one measuring tube is constant or zero.

[0055] According to a twentieth embodiment of the measuring system of the invention, it is further provided that the first and second signal frequencies each correspond to a momentary resonance frequency of the same (natural) oscillation mode of the measuring transducer, for example a first-order (bending) oscillation mode (f1 mode) in which the at least one measuring tube can or does execute (bending) oscillations having a single antinode about an imaginary oscillation axis imaginarily connecting two oscillation nodes of the same (bending) oscillations.

[0056] According to a twenty-first embodiment of the measuring system of the invention, it is further provided that the drive electronics are configured to set or leave the second signal frequency equal to the first signal frequency at least immediately after a change of the drive electronics from the first to the second operating mode.

[0057] According to a twenty-second embodiment of the measuring system of the invention, it is further provided that the drive electronics are arranged to adjust the second signal amplitude such that it deviates from the first signal amplitude by not less than 10% of the first signal amplitude, for example such that the second signal amplitude is less than 80% of the first signal amplitude.

[0058] According to a twenty-third embodiment of the measuring system of the invention, it is further provided that the drive electronics is configured to change from the first operating mode to the second operating mode by the drive electronics switching the drive signal from the first signal amplitude to the second signal amplitude, for example abruptly.

[0059] According to a twenty-fourth embodiment of the measuring system of the invention, it is further provided that the drive electronics is configured to switch from the second operating mode to the first operating mode by the drive electronics switching the drive signal from the second signal amplitude to the first signal amplitude, for example, abruptly. According to a twenty-fifth embodiment of the measuring system of the invention, it is further provided that the drive electronics is configured to operate intermittently, for example, alternately, in the first or second operating mode.

[0060] According to a twenty-sixth embodiment of the measuring system of the invention, the drive electronics is further configured to change from the first operating mode to the second operating mode and back to the first operating mode in a clock or time-controlled manner.

[0061] According to a twenty-seventh embodiment of the measuring system of the invention, the drive electronics is further configured to generate, in a third operating mode, a third electrical drive signal with a third signal frequency, for example, a constant signal and / or a momentary resonance frequency of the measuring transducer and / or corresponding to the first signal frequency and / or the second signal frequency, and a third signal amplitude, for example, a constant signal, which deviates from both the first signal amplitude, for example, by not less than 10% of the first signal amplitude, and from the second signal amplitude, for example, by not less than 10% of the second signal amplitude, for example, namely a third (signal) voltage amplitude and / or a third (signal) current amplitude, and thus to feed electrical power into the excitation arrangement in such a way that the at least one measuring tube generates third useful oscillations,namely, forced mechanical vibrations with a third useful frequency, namely an oscillation frequency corresponding to the third signal frequency of the electrical drive signal and with a third useful amplitude, namely an oscillation amplitude corresponding to the third signal amplitude of the electrical drive signal, and the first vibration measurement signal has a fifth phase angle and the second vibration measurement signal has a sixth phase angle, and the measuring and control electronics are further configured to control the drive electronics in such a way that the drive electronics operates in the third operating mode at least temporarily, for example temporarily and / or for longer than a reciprocal of the third useful frequency and / or for more than 10 ms in each case, and at least one measuring tube (with drive electronics operating in the third operating mode) at least during one,for example, more than one reciprocal of the third useful frequency and / or a third measuring interval lasting longer than 10 ms,

[0062] Further developing this embodiment of the invention, it is further provided that the measuring and control electronics are configured to determine one or more, for example digital, mass flow measured values ​​based on first and second vibration measurement signals received during one or more third measurement intervals and / or to determine one or more phase error measured values ​​(XEIT) based on first and second vibration measurement signals received during one or more first and third measurement intervals and / or during one or more second and third measurement intervals. Alternatively or additionally, the third signal amplitude can deviate from the first signal amplitude by not less than 10% of the first signal amplitude, for example such that the third signal amplitude is more than 120% of the first signal amplitude.

[0063] According to a twenty-eighth embodiment of the measuring system of the invention, it is further provided that the drive electronics is configured to suspend generation of the electrical drive signal in a fourth operating mode, such that during this time no electrical power is fed from the drive electronics into the excitation arrangement. Further developing this embodiment of the invention, it is further provided that the measuring and control electronics is configured to control the drive electronics in such a way that the drive electronics switches from at least one of the first and second operating modes to the fourth operating mode, whereby at least one measuring tube (with the drive electronics operating in the fourth operating mode) is switched on at least during a period corresponding, for example, to more than one reciprocal of the first and / or second useful frequencies and / or lasting longer than 10 ms and / or less than 1 s.fourth measuring interval, and the first vibration measurement signal has a seventh phase angle and the second vibration measurement signal has an eighth phase angle. Advantageously, the measuring and control electronics can further be configured to control the drive electronics such that the drive electronics operate alternately in the first operating mode or in the fourth operating mode, and / or the measuring and control electronics can be configured to control the drive electronics such that the drive electronics operate alternately in the second operating mode or in the fourth operating mode, and / or the measuring and control electronics can be configured to determine one or more phase error measured values ​​based on first and second vibration measurement signals received during one or more first and fourth measuring intervals and / or during one or more second and fourth measuring intervals,and / or the measuring and control electronics can be configured to determine one or more mass flow measurement values ​​based on first and second vibration measurement signals received during one or more fourth measurement intervals.

[0064] According to a twenty-ninth embodiment of the measuring system of the invention, it is further provided that the sensor arrangement for detecting mechanical vibrations of the at least one measuring tube comprises a first vibration sensor (51) providing the first vibration measurement signal—for example, an electrodynamic and / or inlet-side sensor—and a second vibration sensor providing the second vibration measurement signal—for example, an electrodynamic and / or outlet-side sensor and / or identical in construction to the first vibration sensor—for example, no further vibration sensor apart from the first and second vibration sensors. According to a thirtieth embodiment of the measuring system of the invention, it is further provided that the exciter arrangement for exciting vibrations of the at least one measuring tube comprises a first vibration exciter, for example, an electrodynamic and / or single vibration exciter.

[0065] According to a thirty-first embodiment of the measuring system of the invention, it is further provided that the drive electronics are electrically connected to the excitation arrangement.

[0066] According to a thirty-second embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics are electrically coupled to the sensor arrangement.

[0067] According to a thirty-third embodiment of the measuring system of the invention, it is further provided that the measuring and control electronics have a first analog-to-digital converter for the first vibration measurement signal and a second analog-to-digital converter for the second vibration measurement signal.

[0068] According to a first development of the measuring system of the invention, this further comprises: a display element.

[0069] According to a first embodiment of the first further development, it is further provided that the converter circuit is configured to generate control signals for the display element and to output them to the display element.

[0070] According to a second embodiment of the first further development, it is further provided that the display element is configured to receive and process one or more control signals from the converter circuit, for example to display one or more messages transmitted by means of one or more control signals.

[0071] According to a second development of the measuring system of the invention, this further comprises: an operating element.

[0072] According to a first embodiment of the second further development, it is further provided that the operating element is configured to convert one or more manual inputs into one or more control signals, for example containing one or more (control) commands for the converter circuit, and to send them to the converter circuit.

[0073] According to a second embodiment of the second further development, it is further provided that the converter circuit is configured to receive and process one or more control signals from the control element, for example containing one or more (control) commands, for example to execute one or more (control) commands transmitted by means of one or more control signals. A basic idea of ​​the invention is to occasionally suspend the active excitation of the useful oscillations required for measuring the mass flow rate during the detection of said useful oscillations, namely to not feed a driver signal into the excitation arrangement, whereby the - here as a cause of the aforementioned interference components orthe resulting phase error was detected - coupling of the electrical excitation signal into each of the at least two vibration signals as well as the asymmetric driving of the useful vibrations is avoided altogether, and based on both the vibration signals for the actively excited (useful) vibrations and the vibration signals for free (damped) vibrations, the phase error (during operation of the measuring system) is determined, for example namely to quantify it and / or to take the contribution of the phase error into account accordingly when determining the mass flow measured values, in particular to reduce or eliminate it.

[0074] One advantage of the invention is that, for conventional measuring systems, not least Coriolis mass flowmeters, established measuring transducers and converter circuits - for example, those known from the aforementioned US-B 63 11 136 or US-A 2020 / 0408581 or those offered by the applicant itself for Coriolis mass flowmeters (http: / / www.endress.com / de / messgeraete-fuer-die-prozesstechnik / produktfinder7filter.business- area=flow&filter.measuring-principle-parameter=coriolis&filter.text=) - can in principle be adopted, namely, if necessary, even by comparatively minor modifications of the software or firmware of the respective converter circuits, for example by appropriate retrofitting of already installed measuring systems on site.

[0075] 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.

[0076] In detail:

[0077] Fig. 1 shows a vibronic measuring system, here designed as a compact measuring device and / or as a Coriolis mass flow meter; Fig. 2 shows a schematic block diagram of a converter circuit, particularly suitable for a measuring system according to Fig. 1, with a vibration-type measuring transducer connected thereto, or a measuring system according to Fig. 1;

[0078] Fig. 3 shows a phasor diagram (phasor diagram with stationary pointers) for signal components of vibration measurement signals generated by the measuring system according to Fig. 1 or 2 (during a first operating mode);

[0079] Fig. 4 is a phasor diagram for signal components of vibration measurement signals generated by the measuring system according to Figs. 1 and 2 (during a second operating mode);

[0080] Fig. 5 is a phasor diagram for signal components of vibration measurement signals generated by the measuring system according to Figs. 1 and 2 (during the first and second operating modes, respectively);

[0081] Fig. 6 is a phasor diagram for signal components of vibration measurement signals generated by the measuring system according to Figs. 1 and 2 (during a third operating mode); and

[0082] Fig. 7 is a phasor diagram for signal components of vibration measurement signals generated by the measuring system according to Fig. 1 or 2 (during a fourth operating mode).

[0083] In Fig. 1 or 2, a process line (not shown here) - such as a pipeline of an industrial plant, for example a bottling plant or a

[0084] Fueling device - insertable vibronic measuring system for flowable, especially fluid or pourable, media, for example also a medium that is at least temporarily two- or multi-phase or inhomogeneous. The measuring system, designed for example as a Coriolis mass flow meter, is used in particular to measure and / or monitor a mass flow rate m or to determine the

[0085] Mass flow measured values ​​(XM) representing the mass flow rate of a fluid medium being conveyed in the aforementioned process line or at least temporarily flowing therein, for example a gas, a liquid or a dispersion. Furthermore, the measuring system can also be used to additionally determine a density p and / or a viscosity r] of the medium. According to one embodiment of the invention, the measuring system is used to determine mass flow measured values ​​of a medium to be transferred, for example to be handed over from a supplier to a customer in a predetermined or predeterminable quantity, for example a liquefied gas, such as a liquefied gas containing methane and / or ethane and / or propane and / or butane or a liquefied natural gas (LNG) or a mixture of substances formed by means of liquid hydrocarbons, for example petroleum or a liquid fuel.Accordingly, the measuring system can also be designed, for example, as a component of a transfer point for goods transport subject to calibration, such as a refuelling station, and / or as a component of a transfer point of the type shown in the aforementioned WO-A 02 / 060805, WO-A 2008 / 013545, WO-A 2010 / 099276, WO-A 2014 / 151829 or WO-A 2016 / 058745.

[0086] The measuring system - which can also be implemented, for example, as a density and / or viscosity measuring device - comprises a physical-electrical measuring transducer MW which is connected to the process line via an inlet end #111 and an outlet end #112 and which is designed to be flowed through by the measuring medium during operation, as well as an electronic converter circuit US which is electrically coupled to it - in particular supplied with electrical energy during operation by means of internal energy storage and / or externally via a connecting cable.

[0087] Advantageously, the converter circuit US, which can also be programmed and / or remotely parameterized, can also be designed in such a way that, during operation of the measuring system, it can exchange measurement and / or other operating data, such as current measured values ​​or setting and / or diagnostic values ​​used to control the measuring system, with a higher-level electronic data processing system (not shown here), for example a programmable logic controller (PLC), a personal computer and / or a workstation, via a data transmission system, for example a fieldbus system and / or wirelessly via radio. This can include, for example, current measured values ​​or setting and / or diagnostic values ​​used to control the measuring system. Accordingly, the converter circuit US can, for example, have connection electronics which, during operation, are fed by a (central) evaluation and supply unit provided in the aforementioned data processing system and located remote from the measuring system. For example, the converter circuit US (orThe converter circuit (their aforementioned connection electronics) can be designed such that it can be electrically connected to the external electronic data processing system via a two-wire connection 2L, possibly also configured as a 4-20 mA current loop, and can thereby both 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 transmit measured values ​​to the data processing system, for example, by (load) modulation of a direct current supply fed by the evaluation and supply unit. Furthermore, the converter circuit US 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.

[0088] The measuring transducer MW is a vibration-type measuring transducer, namely a measuring transducer with at least one measuring tube 10, with an excitation arrangement 41, and with a sensor arrangement (51, 52). The at least one measuring tube 10 is designed to guide the at least temporarily flowing fluid medium (or to be flowed through by the same medium) and to be vibrated at least temporarily during this time. The at least one measuring tube 10 can be housed within a transducer housing 100, together with the excitation arrangement (41) and the sensor arrangement, as well as any other components of the measuring transducer.Bei dem Meßwandler kann es sich beispielsweise auch um einen aus dem Stand der Technik, nicht zuletzt auch den eingangs erwähnten EP-A 816 807, US-A 2002 / 0033043, US-A 2006 / 0096390, US-A 2007 / 0062309, US-A 2007 / 0119264, US-A 2008 / 0011101 , US-A 2008 / 0047362, US-A 2008 / 0190195, US-A 2008 / 0250871 , US-A 2010 / 0005887, US-A 2010 / 0011882, US-A 2010 / 0257943, US-A 2011 / 0161017, US-A 2011 / 0178738, US-A 2011 / 0219872, US-A 2011 / 0265580, US-A 2011 / 0271756, US-A 2012 / 0123705, US-A 2013 / 0042700, US-A 2016 / 0313162, US-A 2017 / 0261474, US-A 2020 / 0386597, US-A 2020 / 0408581 , US-A 44 91 009, US-A 47 56 198, US-A 47 77 833, US-A 48 01 897, US-A 48 76 898,.

[0089] US-A 49 96 871 , US-A 50 09 109, US-A 52 87 754, US-A 52 91 792, US-A 53 49 872,

[0090] US-A 57 05 754, US-A 57 96 010, US-A 57 96 011 , US-A 58 04 742, US-A 58 31 178,

[0091] US-A 59 45 609, US-A 59 65 824, US-A 60 06 609, US-A 60 92 429, US-B 62 23 605,

[0092] US-B 63 11 136, US-B 64 77 901 , US-B 65 05 518, US-B 65 13 393, US-B 66 51 513,

[0093] US-B 66 66 098, US-B 67 11 958, US-B 68 40 109, US-B 69 20 798, US-B 70 17 424,

[0094] US-B 70 40 181 , US-B 70 77 014, US-B 72 00 503, US-B 72 16 549, US-B 72 96 484,

[0095] US-B 73 25 462, US-B 73 60 451 , US-B 77 92 646, US-B 79 54 388, US-B 83 33 120,

[0096] US-B 86 95 436, WO-A 00 / 19175, WO-A 00 / 34748, WO-A 01 / 02816, WO-A 01 / 71291, WO-A 02 / 060805, WO-A 2005 / 093381, WO-A 2007 / 043996, WO-A 2008 / 013545, WO-A 2008 / 059262, WO-A 2010 / 099276, WO-A 2013 / 092104, WO-A 2014 / 151829, WO-A 2016 / 058745, WO-A 2017 / 069749, WO-A 2017 / 123214, WO-A 2017 / 143579, WO-A 85 / 05677, WO-A 88 / 02853, WO-A 89 / 00679, WO-A 94 / 21999, WO-A 95 / 03528, WO-A 95 / 16897, WO-A 95 / 29385 or WO-A 98 / 02725, WO-A 99 / 40394 known or conventional vibration type measuring transducers.The excitation arrangement of the measuring transducer is accordingly designed to convert electrical power fed thereto into mechanical power causing forced mechanical vibrations of the at least one measuring tube, while the sensor arrangement of the measuring transducer is designed to detect mechanical vibrations of the at least one measuring tube 10 and to provide a first vibration measurement signal s1 representing at least partially vibration movements of the at least one measuring tube, as well as at least one second vibration measurement signal s2 representing at least partially vibration movements of the at least one measuring tube; this in particular in such a way that the same vibration measurement signal corresponds to a change in the mass flow rate of the medium carried in the measuring tube with a change in at least one phase difference Acp12 (Acp12*), namely a change in at least one difference between a phase angle αp1 of the vibration measurement signal s1 (orone of its spectral signal components) and a phase angle cp2 of the vibration measurement signal s2 (or one of its spectral signal components). Furthermore, the vibration measurement signals s1, s2 can have at least one signal frequency and / or signal amplitude dependent on the density and / or viscosity of the medium. According to a further embodiment of the invention, the sensor arrangement according to the invention comprises a first vibration sensor 51 - for example, an electrodynamic, piezoelectric, or capacitive one - attached to the inlet side of at least one measuring tube or arranged in the vicinity thereof, and a second vibration sensor 52 - for example, an electrodynamic, piezoelectric, or capacitive one - attached to the outlet side of at least one measuring tube or arranged in the vicinity thereof. As is quite common with vibration-type measuring transducers and is also shown in Fig.As indicated in Fig. 2, the vibration sensors 51, 52 can, for example, also each be positioned at the same distance from the center of the at least one measuring tube 10. Furthermore, the two vibration sensors 51, 52 can also be the only vibration sensors used to detect vibrations of the at least one measuring tube 10, such that the sensor arrangement has no further vibration sensors apart from the vibration sensors 51, 52. According to a further embodiment of the invention, the exciter arrangement is formed by means of at least one electromechanical—for example, an electrodynamic, electromagnetic, or piezoelectric—vibration exciter 41, which—as also indicated in Fig. 2—can, for example, be positioned centrally of the at least one measuring tube 10 and / or can be the only vibration exciter of the exciter arrangement or of the measuring transducer formed thereby that causes vibrations of the at least one measuring tube.In addition, the measuring transducer can also be provided with, for example, a temperature measuring arrangement 71 for detecting temperatures within the pipe arrangement and / or a strain measuring arrangement for detecting mechanical stresses within the pipe arrangement.

[0097] To process the vibration measurement signals s1, s2 supplied by the transducer, the converter circuit US further comprises a measuring and control electronics DSV. As schematically shown in Fig. 2, this measuring and control electronics DSV is electrically connected to the transducer MW or its sensor arrangement 51, 52 and is configured to receive and evaluate the aforementioned vibration measurement signals s1, s2. Specifically, based on the at least two vibration measurement signals s1, s2, it determines analog and / or digital mass flow measurement values ​​representing the mass flow rate, and optionally also outputs them, for example, in the form of digital values. The vibration measurement signals s1, s2 generated by the measuring transducer MW and fed to the converter circuit US or the measuring and control electronics DSV provided therein, for example via electrical connecting lines, can also be pre-processed there, for example pre-amplified, filtered and digitized.According to a further embodiment of the invention, the measuring and control electronics DSV accordingly has a first measurement signal input for the vibration measurement signal s1 and at least one second measurement signal input for the vibration measurement signal s2, and the measuring and control electronics DSV is further configured to determine the aforementioned phase difference from the same vibration measurement signals s1, s2. Furthermore, the measuring and control electronics DSV can also be configured to determine the respective aforementioned phase angle and / or at least one signal frequency and / or a signal amplitude from at least one of the applied vibration measurement signals s1, s2, for example, to generate, during operation, a sequence of digital phase values ​​representing the respective phase angle and / or a sequence of digital frequency values ​​representing the signal frequency and / or a sequence of digital amplitude values ​​representing the signal amplitude.According to a further embodiment of the invention, the measuring and control electronics DSV has a digital phase output and a digital amplitude output. Furthermore, the measuring and control electronics DSV is also configured to output an amplitude sequence, namely a sequence of digital amplitude values ​​determined based on at least one of the vibration measurement signals, for example, quantifying the signal amplitude of one of the vibration measurement signals, at the amplitude output, and a phase sequence, namely a sequence of digital phase values ​​determined based on the vibration measurement signals, at the phase output.

[0098] The measuring and control electronics DSV can, for example, also be implemented by means of a microcomputer provided in the converter circuit US, for example realized by means of a digital signal processor DSP, and by means of program codes implemented and executed therein. The program codes can, for example, be stored persistently in a non-volatile data memory EEPROM of the microcomputer and, when the microcomputer is started, loaded into a volatile data memory RAM, for example integrated in the microcomputer. The vibration measurement signals s1, s2 are, as already indicated, to be converted into corresponding digital signals for processing in the microcomputer by means of corresponding analog-to-digital converters (A / D converters) of the measuring and control electronics DSV or the converter circuit US formed thereby; see, for example, the aforementioned US-B 63 11 136 or US-A 2011 / 0271756.Accordingly, according to a further embodiment, the measuring and control electronics DSV includes a first analog-to-digital converter for the first vibration measurement signal and a second analog-to-digital converter for the second vibration measurement signal.

[0099] To control or drive the measuring transducer, the converter circuit US, as shown schematically in Fig. 2 in the manner of a block diagram, further comprises drive electronics Exc which is electrically coupled to the excitation arrangement - for example, connected to the excitation arrangement via electrical connecting lines - and to the measuring and control electronics DSV - for example, via a digital bus internal to the converter circuit. The drive electronics Exc and the measuring and control electronics DSV as well as further electronic components of the converter circuit US which serve the operation of the measuring system, such as an internal power supply circuit VS for providing internal DC supply voltages and / or a communication circuit with a higher-level measurement data processing system orThe transmitting and receiving electronics COM serving an external fieldbus can - as is also readily apparent from a synopsis of Figs. 1 and 2 - also be housed, for example, in a corresponding, in particular impact- and / or explosion-proof and / or hermetically sealed, electronics housing 200. This electronics housing 200 can, for example - as also shown in Figs. 1 and 2 - be mounted on the aforementioned converter housing 100 to form a vibronic measuring system or a Coriolis mass flowmeter in a compact design. The electrical connection of the measuring converter MW to the converter circuit US can be made by means of corresponding electrical connecting cables and corresponding cable bushings. The connecting cables can be designed at least partially as electrical conductors, at least partially covered by electrical insulation, e.g.Inform of twisted-pair cables, ribbon cables, and / or coaxial cables. Alternatively or in addition, the connecting lines can also be formed, at least in sections, by conductor tracks on a printed circuit board, especially a flexible one, possibly coated.

[0100] In order to visualize measured values ​​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 and / or to operate the measuring system on site, the measuring system can further comprise a display element HMI1 that communicates at least temporarily with the converter circuit US and / or an operating element HMI2 that communicates at least temporarily with the converter circuit US, such as an LCD, OLED or TFT display placed in the aforementioned electronics housing 200 behind a window provided therein, as well as a corresponding input keyboard and / or a touchscreen (as a combined display and operating element).According to a further embodiment of the invention, the operating element HMI2 is configured to convert one or more manual inputs (from a user of the measuring system) into one or more control signals, for example, also containing one or more (control) commands for the converter circuit US, and to send them to the converter circuit US. Accordingly, the converter circuit US can also be configured to receive and process one or more control signals, possibly also containing one or more (control) commands, from the operating element HMI2, for example, namely to execute one or more (control) commands transmitted via one or more control signals. Alternatively or additionally, the converter circuit can also be configured to generate control signals for the aforementioned display element HMI1 and output them to the display element HMI1.In addition, the display element HMI1 can be configured accordingly to receive and process one or more control signals from the converter circuit US, for example to display one or more messages transmitted by means of one or more control signals. The drive electronics Exc of the measuring system is configured in particular, controlled by the measuring and control electronics DSV and as is quite common with conventional measuring systems of the type in question, to be operated temporarily in a (normal) first operating mode I and, in said first operating mode I, to generate a first electrical drive signal e1 - for example, bipolar and / or at least temporarily periodic, possibly also harmonic - with a first signal frequency, in particular a constant and / or an instantaneous resonant frequency corresponding to a natural oscillation mode inherent in the measuring transducer and a first signal frequency, in particular a constant orto generate a first signal amplitude, which is kept constant, for example a first (signal) voltage amplitude and / or a first (signal) current amplitude, and thus to feed electrical power into the excitation arrangement in such a way that the at least one measuring tube - for example also causing Coriolis forces in the medium flowing through the at least one measuring tube - carries out forced mechanical oscillations with a first useful frequency fNi , namely an oscillation frequency corresponding to the first signal frequency of the electrical drive signal e1, and with a first useful amplitude corresponding to the first signal amplitude of the electrical drive signal e1 - hereinafter first useful oscillations - and that each of the oscillation measurement signals s1, s2 - as also indicated in Fig. 3 - in each case a (useful) signal component S1* or S2*, namely a (spectral) signal component with a signal frequency corresponding to the useful frequency and with in each case a (first orsecond) phase angle; this in particular in such a way that - not least due to the aforementioned Coriolis forces - a corresponding first phase difference Acp12* exists between the two (useful) signal components S1*, S2*. The driver signal e1 can, for example, be a harmonic or sinusoidal electrical (alternating) signal or, for example, a multi-frequency electrical (alternating) signal composed of several (spectral) signal components, but nevertheless containing a spectral (useful) signal component E1 with the first signal amplitude and signal frequency, possibly also periodic for a predeterminable period of time.

[0101] In addition, the measuring and control electronics DSV is also designed to control the drive electronics Exc in such a way that the drive electronics operate in the aforementioned first operating mode I, in particular temporarily and / or for longer than one reciprocal value (1 TN) of the useful frequency fN and / or for more than 10 ms (milliseconds), in particular for more than 10 s, continuously and / or repeatedly, and that at least one measuring tube (with drive electronics operating in the first operating mode) carries out forced oscillations at least during a first measuring interval, in particular corresponding to more than one reciprocal value (1 / frsi) of the useful frequency fN and / or lasting longer than 10 ms. Advantageously, the operating mode I (of the drive electronics Exc) and the first measuring interval (of the measuring and control electronics DSV) can be selected, for example, in such a way that the first useful oscillations carried out during this time, in particular with regard to their useful frequency and / or their useful amplitude, are as stationary or as possible.are designed to be as stable as possible. To set or measure the useful frequency fN, the drive electronics can, for example, have one or more phase-locked loops (PLL), as is quite common in vibronic measuring systems of the type in question or Coriolis mass flow meters. According to a further embodiment of the invention, the drive electronics Exc has a digital frequency output. In addition, the drive electronics Exc is also configured to output a frequency sequence, namely a sequence of digital frequency values ​​quantifying the signal frequency set for the drive signal e1, for example the currently set useful frequency (or the signal frequency of its signal component E1), at the same frequency output.According to a further embodiment of the invention, it is further provided that the aforementioned phase output of the measuring and control electronics DSV is electrically connected to a phase input, formed, for example, by a phase comparator provided within the drive electronics Exc. This phase comparator can, for example, also be configured to detect a phase difference between the aforementioned signal component E1 of the driver signal e1 and at least one of the aforementioned useful components S1*, S2* and / or to determine the extent of this phase difference. Furthermore, the amplitude output of the measuring and control electronics DSV can also be electrically connected to an amplitude input of the drive electronics Exc that detects the amplitude of the signal component or the oscillations excited thereby in the at least one measuring tube.The aforementioned mechanical vibrations excited by the drive electronics Exc and the excitation arrangement 41 connected thereto can - as is quite common in vibronic measuring systems of the type in question, not least also Coriolis mass flow meters - be, for example, (forced) bending vibrations of the at least one measuring tube 10 about an associated rest position, wherein the useful frequency fN can be set, for example, to be an instantaneous resonance frequency of a first-order (bending) vibration mode (f1 mode) having only a single antinode, which also depends on the density and / or viscosity of the medium conveyed in the at least one measuring tube, in which the at least one measuring tube executes (bending) vibrations having a single antinode about an imaginary vibration axis imaginarily connecting two vibration nodes of said (bending) vibrations.As a result of (useful) vibrations of the at least one measuring tube 10, for example the aforementioned bending vibrations, Coriolis forces can be generated in the medium flowing through the at least one measuring tube; this in particular in such a way that each of the aforementioned useful signal components S1*, S2* of the vibration measurement signals s1 and s2 each has a measurement component S1 ' or S2' with a signal frequency corresponding to the useful frequency fN and a (measurement) phase angle (cp1 ', cp2') dependent on the mass flow rate m of the medium flowing through the measuring transducer MW (S1 ' = f(m), S2' = f(m)), thus, as also indicated in Fig. 3, between the measurement component S1 ' of the.

[0102] vibration signal s1 and the measuring component S2' of the vibration signal s2 (nominal) there exists a (measurement) phase difference Acp12' (Acp12' = cp1 ' - cp2' = f(m)) which depends on the same mass flow rate m.

[0103] The measuring and control electronics DSV is accordingly also set up to evaluate the first and second vibration measurement signals s1, s2, namely based on vibration measurement signals s1, s2 received at least during one or more of the aforementioned first measuring intervals, for example based on a corresponding first phase difference Acp12*, namely a difference between the respective phase angle cp1* of the vibration measurement signal s1 (received during one or more first measuring intervals) (or its useful signal component S1*) and the respective phase angle cp2 of the vibration measurement signal s2 (received during one or more first measuring intervals) (or useful signal component S2*), to determine one or more, for example also digital, mass flow measurement values ​​XM, namely the mass flow rate (of the medium carried in at least one measuring tube) representing measurement values.

[0104] According to a further embodiment of the invention, the measuring and control electronics DSV is further configured to initially determine one or more, in particular digital, (first) phase difference measurement values ​​X based on vibration measurement signals s1, s2 received during one or more first measurement intervals. A(pi to determine, each of which represents the first phase difference Acp12* (of the vibration measurement signals s1, s2 received during one or more first measurement intervals), for example, to determine one or more of the aforementioned mass flow measurement values ​​XM using one or more (first) phase difference measurement values ​​X A(piAlternatively or additionally, the measuring and control electronics can be further configured to generate, based on vibration measurement signals s1 received during one or more first measuring intervals, one or more (first) phase angle measurement values ​​X, in particular digital ones, representing the first phase angle cp1* (of the vibration measurement signal s1 received during one or more first measuring intervals). <pi und / oder basierend auf während eines oder mehreren ersten Meßintervallen empfangenen Schwingungsmeßsignalen s2 einen oder mehrere den zweiten Phasenwinkel cp2* (des während eines oder mehreren ersten Meßintervallen empfangenen Schwingungsmeßsignals s2) repräsentierende, insb. digitale, (zweite) Phasenwinkel-Meßwerte X<p2 zu ermitteln. Die vorbezeichneten Phasenwinkel cp1*, cp2* bzw. Phasenwinkel-Meßwerte X<pi , X<p2 können beispielsweise in Referenz zum elektrischen Treibersignal e1 oder auch zu einem, insb.The internal (clock) reference signal of the converter circuit US, generated by the measuring and control electronics DSV or the drive electronics Exc, can be determined at a clock frequency corresponding to the useful frequency, for example, as a phase difference to the driver signal e1 or its useful signal component E1 and / or to the aforementioned (clock) reference signal. As already mentioned, with the drive electronics Exc operating in the first operating mode I or with the driver signal (e1) fed into the excitation arrangement, each of the

[0105] Vibration measurement signals s1, s2 - as also indicated in Fig. 3 - in addition to the aforementioned measurement component S1' or S2', each also has an (unwanted) interference component S1" or S2" with the same frequency but phase-shifted thereto, each with an (interference) amplitude dependent on the driver signal e1 (or its aforementioned signal component E1) and with a respective (interference) phase angle. As also indicated in Fig. 3, the phase angles and / or the amplitudes of the interference components S1" or S2" can differ from one another. The aforementioned interference components S1" or S2" can result, for example, from an electromagnetic coupling of the driver signal into the vibration signals, an asymmetrical (drive) effect of the vibration exciter, or from aging or (over)loading of the transducer or the measuring system formed thereby. Due to the aforementioned interference components S1, S2,The interference component S1" or S2" contained in the useful signal components S1*, S2* is the one between the drive electronics Exc operating in the first operating mode.

[0106] The actually measurable (first) phase difference Acp12* between the useful signal components S1*, S2* does not depend solely on the mass flow rate m (Acp12* = f(m, E1 )) or, conversely, the same phase difference Acp12*, as can be seen from Fig. 3, can deviate significantly from the (measured) phase difference Acp12 established between the measuring components S1 ', S2' (Acp12* Acp12). In other words, the vibration measurement signals s1, s2 or their useful signal components S1*, S2* can have corresponding, by the aforementioned

[0107] Interference component S1" or S2" may have a phase error Err (Err = Acp12* - Acp12).

[0108] In order to detect the aforementioned interference component S1", S2" in the vibration measurement signals s1, s2 or a corresponding phase error Err of the vibration measurement signals as early as possible and, if necessary, also to quantify and / or compensate for the respective phase error during operation of the measuring system, the drive electronics Exc is furthermore set up to be controlled by the measuring and control electronics DSV and occasionally also to be operated in a second operating mode II, and in said second operating mode II a second electrical drive signal e2 - for example a bipolar and / or at least temporarily periodic, if necessary also harmonic - with a, in particularconstant and / or corresponding to the first signal frequency and / or a momentary resonance frequency of a natural oscillation mode inherent in the measuring transducer, for example the aforementioned fundamental (bending) oscillation mode of the measuring tube 10, and a second signal frequency which deviates from the first signal amplitude (of the drive signal e1 or a corresponding preset value therefor), in particular by not less than 10% of the first signal amplitude, in particular a constant or constant second signal amplitude, for example a second (signal) voltage amplitude and / or a second (signal) current amplitude, and thus to feed electrical power into the excitation arrangement; this, for example, also in such a way that the drive electronics Exc (controlled by the measuring and control electronics DSV) operates or is allowed to operate intermittently, in particular alternately, in the first or second operating mode.A corresponding switch from the first operating mode to the second operating mode can be achieved, for example, by the drive electronics adjusting the drive signal from the first signal amplitude to the second signal amplitude, for example, by a continuous (amplitude) sweep or by (step-like) switching. Similarly, a switch from the second operating mode to the first operating mode can also be achieved by the drive electronics switching the drive signal from the second signal amplitude to the first signal amplitude, possibly even step-like.

[0109] As a result of the second drive signal e2, measuring tube 10 (with the drive electronics operating in the second operating mode II) performs second useful oscillations, namely (by means of the drive signal e2) forced mechanical oscillations with a second useful frequency, namely an oscillation frequency corresponding to the second signal frequency of the electrical drive signal e2 and with a second useful amplitude, namely an oscillation amplitude corresponding to the second signal amplitude of the electrical drive signal e2, and accordingly the oscillation measurement signal s1 has a third phase angle cp1** and the oscillation measurement signal s2 has a fourth phase angle cp2**, thus, as also shown in Fig. 4 and evident from Fig. 5, there exists a corresponding second phase difference Acp12** between the two (useful) signal components S1**, S2**. As is readily apparent from a combination of Figs. 3 and 4 and in Fig. 5 (corresponding to such a combination)5 schematically shown - a deviation of the second phase difference Acp12** from a first phase difference Acp12* determined during a first measuring interval initiated (immediately) before and / or (immediately) after the associated second measuring interval corresponds to the aforementioned phase error Err or the same deviation corresponds to the phase error Err, such that a (phase difference) difference measurable or measured between the phase difference Acp12* and the phase difference Acp12** (by means of the measuring and control electronics DSV) is at least approximately equal to or proportional to the phase error Err (Err ~ Acp12** - Acp12*); this is also the case when the first and second signal frequencies are set to be the same or only slightly different from one another. According to a further embodiment of the invention, the first and second signal frequencies are set by means of the drive electronics orthe converter circuit formed thereby is adjustable or set so that each of the first and second signal frequencies (during the first or second operating mode) corresponds to a respective instantaneous resonance frequency of the same (natural) oscillation mode of the measuring transducer, for example the aforementioned (bending) oscillation mode of the first order (f1 mode).

[0110] Accordingly, the drive electronics Exc can advantageously be further configured to set the second signal frequency equal to the first signal frequency, or to leave it set equal to it, at least immediately after the drive electronics switch from the first to the second operating mode. Not least for the purpose of achieving the most significant and easily measurable phase difference possible, the drive electronics Exc, according to a further embodiment of the invention, is further configured to set the second signal amplitude such that it deviates from the first signal amplitude by no less than 10% of the first signal amplitude, for example, less than 80% of the first signal amplitude.

[0111] With knowledge of both the first phase difference Acp12* and the second phase difference Acp12**, or the respective phase angles cp1*, cp2*, cp1**, or cp2** of the respective useful signal components S1*, S2*, or s1**, S2**, the aforementioned phase error Err (Err ~ Acp12* - Acp12**) can thus be readily determined or quantified, at least approximately, during operation of the measuring system. This becomes easier and more precise the less the mass flow fluctuates during operation and the more stable the medium is with regard to its material properties. Accordingly, the measuring and control electronics DSV is also designed to occasionally activate or deactivate the second operating mode II of the drive electronics Exc during operation of the measuring system, for example, in a time- or cycle-controlled and / or event-controlled manner.to cause the at least one measuring tube 10, with the drive electronics Exc in the second operating mode, to carry out the second useful oscillations at least during a - for example, predetermined and / or adaptable - second measuring interval, and also to receive and evaluate the (respective) vibration measurement signals s1, s2 during one or more second measuring intervals, namely to determine one or more, for example digital, phase error measurement values ​​XEIT based on these vibration measurement signals s1, s2 (received during one or more first and second measuring intervals). In addition, the driver signals e1, e2, for example their first and second signal amplitudes, can also be taken into account or used accordingly when determining the phase error measurement values ​​XErr.be used, for example, to normalize or weight the phase differences Acp12**, Acp12* accordingly in the case of time-considerably varying first and / or second signal amplitudes of the respective driver signals e1 and e2.

[0112] As already indicated, the measuring and control electronics DSV can also be configured, for example, to automatically initiate a change in the drive electronics Exc from the first operating mode I to the second operating mode II or vice versa, for example, based on a time or event. Alternatively or additionally, the measuring and control electronics DSV can also be configured to initiate the aforementioned change in the drive electronics Exc from the first operating mode I to the second operating mode II (and vice versa) based on a control signal, possibly also generated externally to the converter circuit US. This control signal can, for example, be generated by means of the aforementioned control element HMI2 or by the aforementioned data processing system (connected to the measuring system) and received via the aforementioned transmitting and receiving electronics COM.For this purpose, the control signal can, for example, contain a control command that (directly) initiates the change from the first operating mode I to the second operating mode II. Alternatively or additionally, the control signal can also contain one or more messages that indicate that the mass flow is stationary and / or that (currently) a density and / or a viscosity or a respective temporal change in the mass flow, the density and / or the viscosity each corresponds to a specified default value, and / or that the medium is homogeneous or inhomogeneous, for example to support a manual change from the first operating mode I to the second operating mode II and / or to enable or effect a conditional change from the first operating mode I to the second operating mode II.

[0113] In the measuring system according to the invention, the phase error measured values ​​XEIT are in particular those measured values ​​which represent, for example quantify, a (measurement) deviation of one or more first phase differences Acp12* (of the vibration measurement signals s1, s2 received during one or more first measuring intervals) from one or more second phase differences Acp12** of the vibration measurement signals s1, s2 received during one or more second measuring intervals.Alternatively or additionally, phase error measured values ​​XErr can also be measured values ​​that represent or quantify a (measurement) deviation of one or more first phase angles cp1* (of the vibration measurement signal s1 received during one or more first measurement intervals) from one or more third phase angles cp1** of the vibration measurement signal s1 received during one or more second measurement intervals and / or a (measurement) deviation of one or more second phase angles cp2* (of the vibration measurement signal s2 received during one or more first measurement intervals) from one or more fourth phase angles cp2** of the vibration measurement signal s2 received during one or more second measurement intervals. Furthermore, one or more phase error measured values ​​XEFF can also represent or quantify a time derivative (of first and / or higher order) of at least one of the aforementioned (measurement) deviations.The aforementioned (measurement) deviation can also be, for example, an absolute or a relative (measurement) deviation. The aforementioned (third) phase angle cp1** and (fourth) phase angle cp2** can, for example, be very easily measured (just like the phase angles cp1* and cp2*, respectively) as a phase difference from the aforementioned (clock) reference signal.

[0114] The second measuring interval (of the measuring and control electronics DSV) or the second operating mode II (of the drive electronics Exc) can advantageously be selected such that the second measuring interval and / or the second operating mode II each lasts longer than 10 ms (milliseconds), for example even more than 100 ms, and / or longer than a reciprocal (1 / fN) of the useful frequency, for example even longer than 5 times the same reciprocal. Alternatively or additionally, the second measuring interval or the second operating mode II can be selected such that they are each shorter than 1 s (second). In addition, the operating mode II and the second measuring interval can advantageously also be selected such that the second useful oscillations carried out during this time are as stationary or as stable as possible, particularly with regard to their useful frequency and / or their useful amplitude.

[0115] According to a further embodiment of the invention, the measuring and control electronics DSV is further configured to effect the change of the drive electronics Exc from the first operating mode I to the second operating mode II in a time-controlled manner or to carry it out in a time-controlled manner, for example in such a way that the change or, conversely, a change from the second operating mode II back to the first operating mode I takes place cyclically or in a time-controlled manner several times within a predetermined or predeterminable period of time.The measuring and control electronics and / or the drive electronics can also be set up, for example, to cyclically change the drive electronics from the first operating mode I to the second operating mode II, such that the drive electronics change several times within one cycle from the first operating mode to the second operating mode and vice versa and / or that the drive electronics are predominantly operated in the first operating mode within one cycle and / or that the drive electronics are operated in the first operating mode at least as often and / or as long within one cycle as in the second operating mode.

[0116] The phase error measured values ​​Err can also be used, for example, to check the measuring system and / or the medium, for example to determine whether the measuring system is subject to a disturbance, possibly even an irreversible one, and / or to determine whether one or more material parameters of the medium, for example a (measured material) density, a (measured material) viscosity or (measured material) consistency, a (measured material) flow index and / or in the case of a multi-phase and / or multi-component flow a component and / or phase ratio (GVF), etc., are outside a specified specification.Alternatively or in addition, phase error measured values ​​Err can also be taken into account accordingly when determining the mass flow measured values ​​XM, for example by the measuring and control electronics also being set up to calculate correction values ​​compensating for the respective phase error Err using one or more phase error measured values ​​XEIT during operation of the measuring system by means of the measuring and control electronics DSV or to determine one or more (future) mass flow measured values ​​XM using one or more phase error measured values ​​XEIT.

[0117] Accordingly, according to a further embodiment of the invention, the measuring and control electronics DSV is configured to determine at least one correction value useful for reducing or compensating a phase error contained in the first phase differences Acp12* (of the vibration measurement signals s1, s2 received during one or more first measurement intervals) using one or more phase error measurement values ​​XEIT, and to take this into account when determining the mass flow measurement values ​​XM ZU or to calculate the mass flow measurement values ​​XM also using the at least one correction value. Alternatively or additionally, the measuring and control electronics DSV can also be configured to determine one or more mass flow measurement values ​​XM based on vibration measurement signals s1, s2 received during one or more second measurement intervals.According to a further embodiment of the invention, the measuring and control electronics are therefore also designed to generate one or more, for example also digital, (second) phase difference measurement values ​​X based on the vibration measurement signals s1, s2 received during one or more second measurement intervals. A(p 2**, such that the same phase difference measured values ​​X A(p 2** are the (second) phase difference Acp12** of the vibration measurement signals s1, s2 (received during one or more second measurement intervals). In addition, the measuring and control electronics DSV can be configured to calculate one or more mass flow measurement values ​​XM using one or more such phase difference measurement values ​​X representing the (second) phase difference Acp12**. A(p2**. Alternatively or additionally, the DSV measurement and control electronics can also be configured to calculate one or more phase error measured values ​​XEIT based on a deviation between the first and second mass flow measured values.

[0118] The above-mentioned determination of the phase error Err, if necessary also the calculation of the above-mentioned correction value which is used to compensate for the phase error Err, as well as the checking of the measuring system or medium can, for example, be based on statistical calculations which are carried out using a plurality of phase error measured values ​​XErr determined in succession in time, or on the basis of key figures of the descriptive and / or inductive statistics determined for the same phase error measured values ​​XEFF; this is advantageously also the case in which the medium flows through the measuring transducer at a mass flow rate which is different from zero, in particular at least approximately constant or stationary for a plurality of successive first and second measuring intervals, and / or in the case in which the medium flows in the measuring transducer at, in particularfor several consecutive first and second measurement intervals, at least approximately constant (material) properties, such as viscosity and / or density, are maintained. The determination of the phase error Err or the corresponding correction value can also be performed, for example, during an (initial) calibration of the measuring system at the manufacturer's facility and / or during an (re-)calibration of the measuring system on-site, possibly even without a (complete) interruption of operation of the industrial plant incorporating the measuring system.

[0119] For this purpose, according to a further embodiment of the invention, the measuring and control electronics DSV is further configured to calculate one or more characteristic values ​​for at least one statistical (measurement system) characteristic value, for example a position measure or a scatter measure of a measurement value ensemble comprising several phase error measured values ​​XEIT, using a plurality of phase error measured values ​​XEIT, for example in order to reduce a (measurement) uncertainty of the phase error measured values ​​XEIT and / or in such a way that one or more characteristic values ​​quantify a (central) tendency of the phase error measured values ​​XErr and / or that one or more characteristic values ​​quantify a scatter range of the phase error measured values ​​XErr around one or more of their position measures. Such a (measurement system) characteristic can be, for example, a mode, a median, an (empirical) mean, an (empirical) variance, an (empirical) standard deviation or a range (of the phase error measured values ​​XErr).Alternatively or in addition, one or more phase error measured values ​​XE^ can also be determined in such a way that they themselves each represent or quantify such a parameter of the (descriptive) statistics, thus one or more phase error measured values ​​XE^ can also themselves serve as key figure values ​​for the at least one statistical (measurement system) key figure. Not least for this purpose, the measuring and control electronics can also be set up to determine one or more phase error measured values ​​XEU in such a way that they each represent or quantify a (central) tendency of the (measurement) deviation of the first phase angle cp1* from the third phase angle cp1** and / or the second phase angle cp2* from the fourth phase angle cp2** and / or the first phase difference Acp12* from the second phase difference Acp12**.quantify and / or that they each represent or quantify a measure of dispersion of the (measurement) deviation of first phase angle cp1* from second phase angles cp1** and / or second phase angle cp2* from fourth phase angles cp2** and / or first phase differences Acp12* from second phase differences Acp12**.For the aforementioned case that one or more phase error measured values ​​XErr are calculated by means of the measuring and control electronics DSV based on a deviation between first and second mass flow measured values, one of the phase error measured values ​​XE^ can also represent a difference between a first mass flow measured value and a second mass flow measured value determined immediately before or after and / or a position measure for a plurality of such differences between first and second mass flow measured values ​​and / or a difference between position measures determined for a plurality of first and second mass flow measured values ​​and / or a dispersion measure for a plurality of such differences between first and second mass flow measured values ​​and / or a difference between dispersion measures determined for a plurality of first and second mass flow measured values.

[0120] A check of the measuring system or medium, for example on site or during ongoing operation of the respective system, can also be carried out by comparing one or more phase error measured values ​​XE^ with one or more (phase error) reference values ​​or (phase error) threshold values; this can be done, for example, in such a way that phase error measured values ​​XErr that represent rapidly varying and / or strongly fluctuating or merely temporary measurement deviations or that exceed a predetermined level are evaluated as an indicator of a disturbance in the medium, for example in the form of a multi-phase flow and / or due to foreign substances entrained in the medium, and / or in such a way that phase error measured values ​​XEIT that represent slowly and / or continuously increasing measurement deviations or that exceed a predetermined level are evaluated as an indicator representing a disturbance in the measuring transducer.

[0121] Accordingly, according to a further embodiment of the invention, the measuring and control electronics DSV is further configured to determine a deviation of one or more phase error measured values ​​XEIT from at least one associated phase error reference value, for example representing a phase error measured value XErr (preliminarily) determined under reference conditions and / or during a (re-)calibration of the measuring system, and / or to compare one or more phase error measured values ​​XEFF with at least one (measuring system-specific) phase error threshold value, for example representing a maximum permissible phase error measured value XE^MAX or a disturbance of the measuring system and / or the measured substance.In addition, the measuring and control electronics DSV can also be configured to output a corresponding (fault) message, for example, also using the aforementioned display element HMI1, if one or more phase error measured values ​​XEIT have exceeded the aforementioned at least one phase error threshold value. The aforementioned phase error reference values ​​or phase error threshold values ​​can be determined at least partially, for example, by the manufacturer (ex works) and / or during on-site calibration of the measuring system (under reference conditions), possibly also on a recurring basis, and stored accordingly in the converter circuit, for example, in a non-volatile (data) memory of the converter circuit US, such as the aforementioned non-volatile data memory EEPROM.

[0122] Even though the phase error Err can, as already mentioned, be determined when the medium flows through the measuring transducer at a mass flow other than zero, it can be advantageous, not least when the measuring system is used in a plant or process with a (highly) dynamic mass flow, such that the respective medium regularly has a non-stationary and / or highly temporally changing mass flow rate, to introduce or provide a mass flow in the plant that is as stationary as possible or at most slightly fluctuating, at least for the short period of time required to determine the phase error measured value XEIT, or conversely to report such a stationary mass flow to the measuring system or an operator on site accordingly. The measuring and control electronics DSV orthe converter circuit US formed thereby is, according to a further embodiment of the invention, further configured to generate a message (when the drive electronics Exc is operating in the first operating mode I or before the drive electronics Exc is switched from the first to the second operating mode), for example to output it by means of the aforementioned control signal and / or to transmit it to the aforementioned display element HMI1, which message indicates or causes the mass flow of the medium carried in the at least one measuring tube to be set to a constant, for example zero, (mass flow) value. Alternatively or additionally, the measuring and control electronics DSV orthe converter circuit US thus formed can also be configured to effect a change, possibly multiple changes, of the drive electronics from the first operating mode to the second operating mode (and vice versa) based on a control signal applied to the converter circuit US, for example triggered by a (start) command transmitted thereby and / or a message transmitted thereby that the mass flow of the medium carried in the at least one measuring tube is constant or zero.

[0123] To further improve the accuracy with which the phase error measured values ​​XEIT can be or are determined, the drive electronics Exc is set up according to a further embodiment of the invention, in a third operating mode III by means of a third electrical drive signal e3, which has a third signal frequency, in particular a constant and / or a momentary resonance frequency of the transducer corresponding to it, and a third signal frequency which deviates from both the first signal amplitude, in particular by not less than 10% of the first signal amplitude, and from the second signal amplitude, in particular by not less than 10% of the second signal amplitude (constant orkept constant) third signal amplitude, for example a third (signal) voltage amplitude and / or a third (signal) current amplitude, to feed electrical power into the excitation arrangement in such a way that the at least one measuring tube carries out third useful oscillations, namely forced mechanical oscillations with a third useful frequency, namely an oscillation frequency corresponding to the third signal frequency of the electrical drive signal and with a third useful amplitude, namely an oscillation amplitude corresponding to the third signal amplitude of the electrical drive signal.

[0124] The third signal frequency can, for example, also correspond to the first signal frequency and / or the second signal frequency. Alternatively or additionally, the third signal amplitude can advantageously be set or deviate from the first signal amplitude by no less than 10% of the first signal amplitude, for example, such that the third signal amplitude is more than 120% of the first signal amplitude.

[0125] Analogous to the conditions during the first and second operating modes or measuring intervals, as a result of the third useful oscillations, the vibration measurement signal s1 has a fifth phase angle cp1*** and the vibration measurement signal s2 has a sixth phase angle cp2***, thus there exists between the vibration measurement signals s1, s2, as also schematically shown in Fig. 6, a corresponding third phase difference Acp12***, such that the phase difference Acp12*** (due to the different signal amplitudes of the respective driver signals e1, e2 and e3) deviates from both the phase difference Acp12* and the phase difference Acp12**; this in particular.also in such a way that a phase difference difference measurable between the phase difference Acp12* and the phase difference Acp12*** or the phase difference Acp12** and the phase difference Acp 12*** is equally proportional to the phase error Err (Err ~ Acp12*- Acp12*** = Acp12** - Acp12***) as the aforementioned phase difference difference (Acp12* - Acp12**) between the phase difference Acp12* and the phase difference Acp12**. In addition, the measuring and control electronics DSV is also set up to control the drive electronics Exc in such a way that it operates in the third operating mode III at least temporarily, in particular temporarily and / or for longer than a reciprocal of the third useful frequency and / or for more than 10 ms in each case, and that at least one measuring tube (with drive electronics operating in the third operating mode) at least during one, in particularexecutes third (useful) oscillations corresponding to more than one reciprocal of the third useful frequency and / or lasting longer than 10 ms. Furthermore, the measuring and control electronics DSV can advantageously also be configured to determine one or more phase error measured values ​​Err based on first and second vibration measurement signals received during one or more first and third measuring intervals and / or during one or more second and third measuring intervals. Alternatively or additionally, the measuring and control electronics can also be configured to determine one or more of the mass flow measured values ​​XM based on vibration measurement signals s1, s2 received during one or more third measuring intervals.

[0126] Alternatively or in addition to the aforementioned operating mode III, the drive electronics Exc can also be configured to suspend generation of the electrical drive signal in a fourth operating mode IV, such that during this time no electrical power is fed into the excitation arrangement from the drive electronics Exc. In addition, the measuring and control electronics (DSV) can advantageously be configured to control the drive electronics Exc in such a way that the drive electronics Exc changes from at least one of the first operating modes I and / or from at least one of the second operating modes II to the fourth operating mode IV, as a result of which at least one measuring tube (with the drive electronics operating in the fourth operating mode) is switched on at least during one, in particular more than one, reciprocal of the (previous) first orsecond useful frequencies and / or lasting longer than 10 ms and / or less than 1 s, and - as also schematically shown in Fig. 7 - the vibration measurement signal s1 has a corresponding seventh phase angle cp1. # and the vibration measurement signal s2 has a corresponding eighth phase angle cp2 # have.

[0127] As can be seen from Fig. 7, a temporary interruption or switching off of the respective driver signal e1, e2 or e3 and a corresponding temporary suspension of the current supply to the excitation arrangement may, on the one hand, lead to the (signal) amplitude (|S1 # |, |S2 # |) each of the useful signal components S1 # , S2 # of the vibration measurement signals s1 , s2 generated during operating mode IV compared to the

[0128] The amplitudes (|S1*|, |S2*|, |S1**|, |S2**| or |S1***|, |S2***|) of each of the useful signal components (S1*, S2*, S1**, S2** or S1***, S2***) previously recorded when the drive electronics Exc was operating in operating mode I, II or III can decrease significantly. However, due to the fact that no drive signals are generated by the drive electronics Exc, despite the measuring tube (still) oscillating at the respective useful frequency, the vibration measurement signals s1, s2 or their useful signal components S1 # , S2 # Interference components of the aforementioned type are hardly or not at all present, thus phase error Err is also essentially eliminated (Err = 0). As a result, the phase angles cp (measured during the fourth measurement interval) correspond to 1 # , cp2 # (at least approximately) the previously designated (measurement) phase angles cp1 ' or cp2' (cp1 # = cp1 ', cp2 #= cp2') or a corresponding fourth phase difference Acp12 # between the useful signal components S1 # , S2 # (at least approximately) the aforementioned (measurement) phase difference Acp12' (Acp12 # = Acp12'). Accordingly, according to a further embodiment of the invention, the measuring and control electronics DSV is further configured to receive and evaluate the (respective) vibration measurement signals s1, s2 during one or more such fourth measuring intervals, for example, based on vibration measurement signals s1, s2 received during one or more fourth measuring intervals, one or more (measurement) phase difference measurement values ​​X each representing the (measurement) phase difference Acp12' A(p4 or to determine one or more mass flow measurement values ​​XM based on vibration measurement signals s1, s2 received during one or more fourth measurement intervals, if necessary also using one or more of the aforementioned (measurement) phase difference measurement values ​​X A(p 4.

Claims

PATENT CLAIMS 1. Vibronic measuring system, in particular Coriolis mass flow meter, comprising: - a transducer - with at least one measuring tube, - with an excitation arrangement - and with a sensor arrangement; - and an electronic converter circuit (US) electrically coupled to both the excitation arrangement and the sensor arrangement, in particular formed and / or programmable by means of at least one microprocessor - with measuring and control electronics (DSV) - and with drive electronics (Exc) connected to the measuring and control electronics, in particular electrically, and / or controlled by the measuring and control electronics; - wherein the measuring tube is designed to carry a fluid measuring substance, in particular a gas, a liquid or a dispersion, which flows at least temporarily and is allowed to vibrate during this time; - wherein the excitation arrangement is configured to convert electrical power fed thereto into mechanical power causing forced mechanical oscillations of the at least one measuring tube; - wherein the sensor arrangement is configured to detect mechanical vibrations of the at least one measuring tube and to provide a first vibration measurement signal (s1) representing at least partially vibration movements of the at least one measuring tube and at least one second vibration measurement signal (s2) representing at least partially vibration movements of the at least one measuring tube, in particular such that the same first and second vibration measurement signals follow a change in a mass flow rate of the medium being conveyed in the measuring tube with a change in a phase difference, namely a change in a difference between a phase angle of the first vibration measurement signal and a phase angle of the second vibration measurement signal; - wherein the drive electronics (Exc) is set up, in a first operating mode (I), to generate a first electrical drive signal (e1) with a first signal frequency, in particular a constant and / or an instantaneous resonance frequency corresponding to a natural oscillation mode inherent in the measuring transducer, and a first signal amplitude, in particular a constant. namely a first (signal) voltage amplitude and / or a first (signal) current amplitude, and thus to feed electrical power into the excitation arrangement in such a way that - the at least one measuring tube performs first useful oscillations, namely forced mechanical oscillations with a first useful frequency, namely an oscillation frequency corresponding to the first signal frequency (of the first electrical drive signal) and with a first useful amplitude, namely an oscillation amplitude corresponding to the first signal amplitude (of the first electrical drive signal) - and the first vibration measurement signal (s1) has a first phase angle (cp1*) and the second vibration measurement signal (s2) has a second phase angle (cp2*), - and wherein the drive electronics (Exc) is configured, in a second operating mode (II), to generate a second electrical drive signal (e2) with a second signal frequency, in particular a constant and / or a momentary resonance frequency of a natural oscillation mode inherent in the transducer and / or corresponding to the first signal frequency, and a second signal amplitude, in particular a constant, deviating from the first signal amplitude, in particular by not less than 10% of the first signal amplitude, in particular a second (signal) voltage amplitude and / or a second (signal) current amplitude, and thus to feed electrical power into the excitation arrangement, such that - the at least one measuring tube performs second useful oscillations, namely forced mechanical oscillations with a second useful frequency, namely an oscillation frequency corresponding to the second signal frequency (of the second electrical drive signal) and with a second useful amplitude, namely an oscillation amplitude corresponding to the second signal amplitude (of the second electrical drive signal) - and the first vibration measurement signal (s1) has a third phase angle (cp1**) and the second vibration measurement signal (s2) has a fourth phase angle (cp2**); - wherein the measuring and control electronics (DSV) are arranged to control the drive electronics in such a way, - that the drive electronics (Exc) operates in the first operating mode at least temporarily, in particular temporarily and / or for longer than a reciprocal of the first useful frequency and / or for more than 10 ms in each case, and that at least one measuring tube (with drive electronics operating in the first operating mode) carries out first (useful) oscillations at least during a first measuring interval, in particular corresponding to more than a reciprocal of the first useful frequency and / or lasting longer than 10 ms, and that the drive electronics (Exc) operates in the second operating mode at least temporarily, in particular temporarily and / or for longer than a reciprocal of the second useful frequency and / or for more than 10 ms in each case and / or intermittently to the first operating mode, and that at least one measuring tube (with drive electronics operating in the second operating mode) performs second (useful) oscillations at least during a second measuring interval, in particular one corresponding to more than one reciprocal of the second useful frequency and / or lasting longer than 10 ms; - and wherein the measuring and control electronics are arranged to receive and evaluate the first and second vibration measurement signals, namely - to determine one or more, in particular digital, mass flow measurement values ​​(XM), namely the mass flow rate (of the medium conveyed in at least one measuring tube), based on first and second vibration measurement signals received at least during one or more first measurement intervals, - as well as based on first and second vibration measurement signals received during one or more first and second measurement intervals, one or more, in particular digital, phase error measurement values ​​(XEIT), namely one, in particular absolute or relative, (measurement) deviation of one or more first phase angles (of the first vibration measurement signal received during one or more first measurement intervals) from one or more third phase angles (of the first vibration measurement signal received during one or more second measurement intervals) and / or one, in particular absolute or relative, (measurement) deviation of one or more second phase angles (of the second vibration measurement signal received during one or more first measurement intervals) from one or more fourth phase angles (of the second vibration measurement signal received during one or more second measurement intervals) and / or one, in particularto determine the absolute or relative (measurement) deviation of one or more first phase differences (Acp12*) of the first and second vibration measurement signals received during one or more first measurement intervals from one or more second phase differences (Acp12**) of the first and second vibration measurement signals received during one or more second measurement intervals.

2. Measuring system according to one of the preceding claims, - wherein the measuring and control electronics are configured to determine one or more mass flow measured values ​​(XM) using one or more phase error measured values ​​(XEIT), in particular in such a way that the measuring and control electronics are configured to determine at least one correction value for reducing or compensating a phase error contained in the first phase differences (of the first and second vibration measurement signals received during one or more first measuring intervals) using one or more phase error measured values ​​(XEIT) and in determining the Mass flow measured values ​​(XM) TO be taken into account or the mass flow measured values ​​(XM) to be calculated using the at least one correction value; and / or - wherein the measuring and control electronics are configured to calculate, using a plurality of phase error measured values ​​(XEIT), one or more key figure values ​​for at least one statistical (measurement system) key figure, in particular a position measure or a dispersion measure of a measurement value ensemble comprising a plurality of phase error measured values ​​(XEIT), in particular in such a way that one or more key figure values ​​quantify a (central) tendency of the phase error measured values ​​(XEIT) and / or that one or more key figure values ​​quantify a dispersion parameter of the phase error measured values ​​(XEIT).

3. Measuring system according to one of the preceding claims, - wherein one or more phase error measurement values ​​(XErr) represent, in particular quantify, a (central) tendency, in particular a mode, a median, an (empirical) mean value, of the (measurement) deviation of one or more first phase angles (cp1*) from one or more third phase angles (cp1**); and / or - wherein one or more phase error measurement values ​​(XE^) represent, in particular quantify, a (central) tendency, in particular a mode, a median, an (empirical) mean, of the (measurement) deviation of one or more second phase angles (cp2*) from one or more fourth phase angles (cp2**); and / or - wherein one or more phase error measurement values ​​(XE^) represent, in particular quantify, a (central) tendency, in particular a mode, a median, an (empirical) mean, of the (measurement) deviation of one or more first phase differences (Acp12*) from one or more second phase differences (Acp12**); and / or - wherein one or more phase error measured values ​​(XE^) represent, in particular quantify, a dispersion parameter, in particular an (empirical) variance, an (empirical) standard deviation or a range, of the (measurement) deviation of one or more first phase angles (Acp1*) from one or more third phase angles (cp1**); and / or - wherein one or more phase error measured values ​​(XE^) represent, in particular quantify, a dispersion parameter, in particular an (empirical) variance, an (empirical) standard deviation or a range, of the (measurement) deviation of one or more second phase angles (cp2*) from one or more fourth phase angles (cp2**); and / or - wherein one or more phase error measured values ​​(XE^) represent, in particular quantify, a dispersion parameter, in particular an (empirical) variance, an (empirical) standard deviation or a range, of the (measurement) deviation of one or more first phase differences (Acp12*) from one or more second phase differences (Acp12**).

4. Measuring system according to one of the preceding claims, - wherein the measuring and control electronics are configured to determine a deviation of one or more phase error measured values ​​(XEIT) from at least one phase error reference value, in particular representing a phase error measured value (XEIT) determined under reference conditions and / or during a (re-)calibration of the measuring system; and / or - wherein the measuring and control electronics are configured to compare one or more phase error measured values ​​(XEIT) with at least one phase error threshold value, in particular a measuring system-specific and / or a maximum permissible phase error measured value (XE^MAX) representing a fault in the measuring system and / or the measured substance, in particular to output a (fault) message if one or more Phase error measurements (XEIT) have exceeded the least one phase error threshold.

5. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are arranged to determine one or more mass flow measured values ​​(XM) based also on first and second vibration measuring signals received during one or more second measuring intervals.

6. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are arranged, based on first vibration measurement signals received during one or more first measuring intervals, to generate one or more (first) phase angle measurement values ​​(X <pi) zu ermitteln.

7. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are configured to determine, based on second vibration measurement signals received during one or more first measurement intervals, one or more (second) phase angle measurement values ​​(X^), in particular digital, representing the second phase angle (of the second vibration measurement signal received during one or more first measurement intervals).

8. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are configured to determine, based on first vibration measurement signals received during one or more second measurement intervals, one or more (third) phase angle measurement values ​​(X^), in particular digital, representing the third phase angle (of the first vibration measurement signal received during one or more second measurement intervals).

9. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are configured to determine, based on second vibration measurement signals received during one or more second measurement intervals, one or more (fourth) phase angle measurement values ​​(X^), in particular digital, representing the fourth phase angle (of the second vibration measurement signal received during one or more second measurement intervals).

10. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are arranged to generate one or more, in particular digital, (first) phase difference measurement values ​​(X A <pi), nämlich die (erste) Phasendifferenz der (während eines oder mehreren ersten Meßintervallen empfangenen) ersten und zweiten Schwingungsmeßsignale repräsentierende Meßwerte zu ermitteln. 11 . Measuring system according to the preceding claim, wherein the measuring and control electronics are arranged to calculate one or more mass flow measured values ​​(XM) using one or more first phase difference measured values ​​(X A(p i) to be determined.

12. Measuring system according to one of the preceding claims, wherein the measuring and control electronics are arranged to generate one or more, in particular digital, (second) phase difference measurement values ​​(X A(p 2), namely to determine the (second) phase difference of the measured values ​​representing the first and second vibration measurement signals (received during one or more second measurement intervals).

13. Measuring system according to the preceding claim, wherein the measuring and control electronics are arranged to calculate one or more mass flow measured values ​​(XM) using one or more second phase difference measured values ​​(X A(p 2) to be determined.

14. Measuring system according to one of the preceding claims, - wherein the converter circuit, in particular its measuring and control electronics, is configured, in particular when the drive electronics are operating in the first operating mode or before switching the drive electronics from the first to the second operating mode, to generate a message, in particular by means of a control signal and / or to transmit it to a display element of the measuring system, which indicates or causes the mass flow of the medium conveyed in the at least one measuring tube to be set to a constant, in particular zero, (mass flow) value; and / or - wherein the converter circuit, in particular its measuring and control electronics, is set up to effect a change, in particular multiple changes, of the drive electronics from the first operating mode to the second operating mode (and vice versa) automatically, in particular in a time- and / or event-controlled manner, and / or based on a control signal applied to the converter circuit, in particular triggered by a (start) command transmitted thereby and / or a message transmitted thereby that the mass flow of the medium being conveyed in the at least one measuring tube is constant or zero.

15. Measuring system according to one of the preceding claims, further comprising: a display element (HMI1).

16. Measuring system according to the previous claim, - wherein the converter circuit is configured to generate control signals for the display element (HMI1) and to output them to the display element (HM11); and / or - wherein the display element (H Ml 1 ) is configured to receive and process one or more control signals from the converter circuit, in particular to display one or more messages transmitted by means of one or more control signals.

17. Measuring system according to one of the preceding claims, further comprising: an operating element (HMI2).

18. Measuring system according to the previous claim, - wherein the control element (HMI2) is configured to convert one or more manual inputs into one or more control signals, in particular containing one or more (control) commands for the converter circuit, and to send them to the converter circuit; and / or - wherein the converter circuit is configured to receive and process one or more control signals from the control element (HMI2), in particular one or more (control) commands containing one or more, in particular to execute one or more (control) commands transmitted by means of one or more control signals.

19. Measuring system according to one of the preceding claims, - wherein the sensor arrangement for detecting mechanical vibrations of the at least one measuring tube comprises a first vibration sensor (51) providing the first vibration measurement signal - in particular an electrodynamic and / or inlet-side vibration sensor - and a second vibration sensor (52) providing the second vibration measurement signal - in particular an electrodynamic and / or outlet-side vibration sensor and / or structurally identical to the first vibration sensor - in particular no further vibration sensor apart from the first and second vibration sensors; and / or - wherein the exciter arrangement for exciting vibrations of the at least one measuring tube comprises a first vibration exciter (41), in particular an electrodynamic and / or single vibration exciter; and / or - wherein the drive electronics are electrically connected to the excitation arrangement; and / or - wherein the measuring and control electronics are electrically coupled to the sensor arrangement; and / or - wherein the measuring and control electronics comprises a first analog-to-digital converter for the first vibration measurement signal and a second analog-to-digital converter for the second vibration measurement signal.

20. Measuring system according to one of the preceding claims, - wherein the first and second signal frequencies each correspond to a momentary resonance frequency of the same (natural) oscillation mode of the measuring transducer, in particular a first-order (bending) oscillation mode (f1 mode) in which the at least one measuring tube can or does execute (bending) oscillations having a single antinode about an imaginary oscillation axis imaginarily connecting two oscillation nodes of the same (bending) oscillations; and / or - wherein the drive electronics (Exc) are configured to set or leave the second signal frequency equal to the first signal frequency at least immediately after a change of the drive electronics from the first to the second operating mode; and / or - wherein the drive electronics (Exc) are arranged to adjust the second signal amplitude such that it deviates from the first signal amplitude by not less than 10% of the first signal amplitude, in particular such that the second signal amplitude is less than 80% of the first signal amplitude; and / or - wherein the drive electronics are configured to switch from the first operating mode to the second operating mode by switching the drive signal from the first signal amplitude to the second signal amplitude, in particular abruptly; and / or - wherein the drive electronics are configured to switch from the second operating mode to the first operating mode by switching the drive signal from the second signal amplitude to the first signal amplitude, in particular abruptly; and / or - wherein the drive electronics are designed to operate intermittently, in particular alternately, in the first or second operating mode; and / or - wherein the drive electronics are configured to change from the first operating mode to the second operating mode and back to the first operating mode in a cycle or time controlled manner. 21 . Measuring system according to one of the preceding claims, - wherein the drive electronics (Exc) is configured, in a third operating mode (III), to generate a third electrical drive signal (e3) with a third signal frequency, in particular a constant signal and / or a momentary resonance frequency of the transducer corresponding to the first signal frequency and / or the second signal frequency, and a third signal amplitude, in particular a constant signal, deviating from both the first signal amplitude, in particular by not less than 10% of the first signal amplitude, and the second signal amplitude, in particular by not less than 10% of the second signal amplitude, and thereby to feed electrical power into the excitation arrangement, such that - the at least one measuring tube carries out third useful oscillations, namely forced mechanical oscillations with a third useful frequency, namely an oscillation frequency corresponding to the third signal frequency of the electrical drive signal and with a third useful amplitude, namely an oscillation amplitude corresponding to the third signal amplitude of the electrical drive signal - and the first vibration measurement signal (s1) has a fifth phase angle (cp1***) and the second vibration measurement signal (s2) has a sixth phase angle; - and wherein the measuring and control electronics (DSV) are configured to control the drive electronics in such a way that the drive electronics operate in the third operating mode at least temporarily, in particular temporarily and / or for longer than a reciprocal of the third useful frequency and / or for more than 10 ms in each case, and at least one measuring tube (with drive electronics operating in the third operating mode) executes third (useful) oscillations at least during a third measuring interval, in particular corresponding to more than a reciprocal of the third useful frequency and / or for longer than 10 ms.

22. Measuring system according to the previous claim, - wherein the measuring and control electronics are configured to determine one or more, in particular digital, mass flow measurement values ​​(XM) based on first and second vibration measurement signals received during one or more third measurement intervals; and / or - wherein the measuring and control electronics are configured to determine one or more phase error measurement values ​​(XEIT) based on first and second vibration measurement signals received during one or more first and third measurement intervals and / or during one or more second and third measurement intervals; and / or - wherein the third signal amplitude deviates from the first signal amplitude by not less than 10% of the first signal amplitude, in particular such that the third signal amplitude is more than 120% of the first signal amplitude.

23. Measuring system according to one of the preceding claims, wherein the drive electronics (Exc) are arranged to suspend generation of the electrical drive signal in a fourth operating mode (IV) such that during this time no electrical power is fed into the excitation arrangement by the drive electronics (Exc).

24. Measuring system according to the preceding claim, wherein the measuring and control electronics (DSV) are configured to control the drive electronics in such a way that the drive electronics switches from at least one of the first and second operating modes to the fourth operating mode (IV), whereby at least one measuring tube (with drive electronics operating in the fourth operating mode) carries out free damped oscillations at least during a fourth measuring interval, in particular corresponding to more than one reciprocal of the first and / or second useful frequencies and / or lasting longer than 10 ms and / or less than 1 s, and the first oscillation measurement signal (s1) has a seventh phase angle (ωp1 # ) and the second vibration measurement signal (s2) has an eighth phase angle (cp2 # ).

25. Measuring system according to the previous claim, - wherein the measuring and control electronics (DSV) are arranged to control the drive electronics in such a way that the drive electronics operates alternately in the first operating mode (I) or in the fourth operating mode (IV); and / or - wherein the measuring and control electronics (DSV) are arranged to control the drive electronics in such a way that the drive electronics operates alternately in the second operating mode (I) or in the fourth operating mode (IV); and / or - wherein the measuring and control electronics are configured to determine one or more phase error measurement values ​​(XEIT) based on first and second vibration measurement signals received during one or more first and fourth measurement intervals and / or during one or more second and fourth measurement intervals; and / or - wherein the measuring and control electronics are designed to control one or more Mass flow measurement values ​​based on first and second vibration measurement signals received during one or more fourth measurement intervals.

26. Use of a measuring system according to one of the preceding claims for measuring and / or Monitoring a fluid medium, in particular a gas, a liquid or a dispersion, flowing at least temporarily in a pipeline, in particular at least temporarily inhomogeneous and / or at least temporarily 2- or multi-phase.

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