Interfered flow measurement method, magnetic inductive flowmeter and computer program product

Abstract

A method (100) for measuring a flow (15) in a pipe (11) by means of a magnetic-inductive flowmeter (10) is disclosed. The method (100) comprises a first step (110) in which a magnetic coil (12) of the magnetic-inductive flowmeter (10) is excited at a pulse frequency (19) with a rectangular signal (21) and a measurement signal (20) is captured. In a second step (120) following on, a first measurement value section (24) of the measurement signal (20) is captured, which comprises a first and a second sub-section (32, 33). A third step (130) is carried out in which an average value (37) of the measurement signal (20) in the first and second sub-section (32, 33) is respectively derived. Interferences (38) of the measurement signal (20) are thereby identified. The invention also discloses a magnetic-inductive flowmeter (10) with a control unit (30), which is designed via a suitable computer program product (50) to carry out such a method (100). Likewise, the invention discloses a computer program product (80), which is configured as a digital twin and is arranged to simulate the operating behavior of such a flowmeter (10).

Description

Technical Field

[0001] This invention discloses a method for measuring flow rate in a tube using a magnetic induction flow meter. Similarly, this invention discloses a computer program product suitable for implementing at least one such method. This invention also discloses a control unit that provides such a computer program product and a correspondingly assembled magnetic induction flow meter. Furthermore, this invention discloses a computer program product for simulating the operating behavior of such a magnetic induction flow meter. Background Technology

[0002] Publication DE 102 56 103 A1 discloses a method for determining the insecuritys of a measurement method utilizing measurement frequency processing, which can be employed in a magnetic induction flowmeter. In this method, rectangular pulses are alternatively excited and time intervals are evaluated separately. For evaluation, an oscillation variation is first made.

[0003] DE 10 2019 103 501 A1 illustrates a method for operating an electromagnetically inductive flow measurement device, in which air bubbles are identified in a measuring tube. Rectangular pulses are generated and evaluated to determine the flow velocity in the measuring tube. Measurement signals are sampled multiple times during the intervals between the rectangular pulses, and an average value is formed from the measurement signals captured at each interval. The difference between the multiple average values ​​over multiple cycles is formed and compared to a threshold. In a filled measuring tube, this difference is approximately zero.

[0004] Publication DE 10 2004 031 638 A1 discloses a method for operating a flow measurement device with electromagnetic induction, in which interference signals are minimized. This is achieved by a vector product of the received signal spectrum containing the interference signal and a reference voltage. From this, the effective signal portion is obtained using an inverse Fourier transform, and the flow rate is calculated based on it.

[0005] A method for spectral analysis on a magnetic flow meter, in which the flow measurement is subject to interference, is known from patent application US 6,615,149 B1. Interference within an effective frequency range of 50 Hz or 60 Hz is determined using Fourier analysis, and an alarm is sent to the user where possible.

[0006] Publication DE 694 20 783 T2 discloses an electromagnetic flowmeter having a measuring tube and a device for applying an alternating magnetic field. The flowmeter has a sampling device for detecting the electromotive force induced by the magnetic field. This sampling device is designed to perform detection at multiple time points along the same direction within one cycle.

[0007] A method for operating a measuring device is known from the published unexamined patent application DE 10 2005 018 179 A1, wherein the measuring operation is timed at a measuring frequency. During the measuring operation, frequency analysis is performed on the measuring data, and the measuring frequency is automatically controlled based on the spectrum thus detected. Summary of the Invention

[0008] Flow meters are used in various applications, such as chemical plants, to determine the flow rate of fluids or gases. Here, flow meters are frequently subjected to interference, which affects the accuracy of the measurement. Cost-effective flow meters are also a goal. Therefore, there are requirements for flow meters that are resistant to interference, allow accurate measurement, and are economically manufactured. The object of this invention is to provide a feasible solution that offers an improvement in at least one of the described aspects.

[0009] This objective is achieved by a method according to the invention, which measures the flow rate of a liquid in a pipe. A magnetic induction flowmeter, fixed to the pipe, is used for this purpose. The magnetic induction flowmeter has a magnetic coil, through which a magnetic field is induced on the cross-section of the pipe, interacting with the flow-loaded particles in the pipe. This generates a voltage perpendicularly in the magnetic field on the cross-section of the pipe, which can be captured by a suitably mounted voltage sensor. In the first step of the method, the magnetic coil is excited using a rectangular signal with a pulse frequency. The rectangular signal, also called a box signal, can here be generated by the superposition of multiple sinusoidal signals. A voltage is generated on the cross-section of the pipe by the rectangular signal, which is captured as a measurement signal. The measurement signal is also substantially rectangular. The amplitude of the measurement signal corresponds to the flow rate to be measured in the pipe. The method includes a second step in which a first measurement value segment of the measurement signal is captured. The measurement value segment is a segment of the measurement signal in which the amplitude, i.e., the amplitude value, is received for at least a short time. The amplitude, on the other hand, depends on the flow velocity in the pipe, i.e., the flow rate. The first measurement value segment includes first and second sub-segments, which can be considered and evaluated separately. In particular, the measurement signals can be processed separately for the first and second sub-segments.

[0010] Furthermore, the method includes a third step in which average values ​​of the measurement signal are formed for the first and second sub-segments of the first measurement value segment, respectively. Specifically, the average amplitude value of the measurement signal can be formed via the first or second sub-segment as the average value. In an interference-free measurement signal, a constant amplitude value is received in the first measurement value segment via the first or second sub-segment. The difference between the average values ​​in the first and second sub-segments is substantially zero under the condition of equal length. When interference of corresponding flatness and opposite phase is present, the average values ​​in the first and second sub-segments are different, causing the difference between them to deviate from zero. When the average values ​​in the first and second sub-segments deviate from each other by at least one adjustable interference threshold, interference is identified in the method according to the invention. The interference threshold can be predetermined, for example, by user input or by calculation, so that the sensitivity of such interference identification can be appropriately matched to the current application. When interference is identified, the evaluation of the measurement signal can be matched so as to accurately measure the flow rate in the tube. The formation of the average values ​​of the portions of the measurement signal, i.e., the measurement value segment and its sub-ranges, can be achieved with reduced computational overhead. In an additional step, the sub-segments are offset such that, for example, the last 25% of the first and measured value segments belong to the first sub-segment, and the middle 50% of the measured value segments belong to the second sub-segment. The difference between the average values ​​of the sub-segments is then recalculated.

[0011] The described steps implement quadrature amplitude modulation of a rectangular signal followed by low-pass filtering, where the difference can be interpreted as the real and imaginary parts of the demodulated signal. The value of the complex number then corresponds to the amplitude value of the interference signal. Evaluation can be performed over multiple cycles of the excitation signal. The frequency of the interference detection is selected by choosing a sub-segment.

[0012] The method according to the invention can be quickly implemented on simple hardware because it generates averages and differences. Furthermore, interference in the measurement signal can be easily identified using unexpectedly high reliability. With appropriate compensation measures, a corrected amplitude value can be obtained, representing a precise measure of the flow rate present in the pipe.

[0013] According to the invention, the rectangular signal that excites the magnetic coil has an inactive phase that is independent of the first and / or second measurement segments. The inactive phase occurs between the two measurement segments and essentially defines the time interval, which is used to generate the amplitude value of the measurement signal. The polarity of the generated magnetic field is changed during the inactive phase. When aperiodic interference is identified in the stated method, the inactive phase can be adjusted to achieve the target sampling rate. Therefore, the magnetic induction flowmeter can, for example, be matched with an additional evaluation unit that further processes the measurement results of the magnetic induction flowmeter. Alternatively or additionally, the inactive phase can also be shortened to achieve an increased sampling rate. This thus further exhausts the overall technical potential of the magnetic induction flowmeter. In particular, the technical potential of the magnetic induction flowmeter is limited by reducing the duration required for the polarity change of the magnetic field during the inactive phase; however, it can be fully utilized with the stated solution.

[0014] Furthermore, according to the invention, the method includes an additional step in which the pulse duration of the rectangular signal is matched, i.e., corrected, is the overall duration of the substantially corresponding measurement segment and / or the duration of the inactive phase. This matching is used to compensate for interference effects in sequentially consecutive measurement segments. Such matching of the pulse duration and / or the duration of the inactive phase allows for, for example, in reverse compensation of the interference effect on the measurement signal by obtaining double the amplitude, as exemplarily described above. This particularly reduces the effect of periodic interference, i.e., interference coupled to the pulse frequency. The computational cost for compensating for interference or its effects is thus further reduced, thereby providing improved robustness to the method while broadening its application range. The so-called compensation can also be achieved via more than two measurement segments. This may be necessary when the interference signal is found to be at a low frequency. The amplitude values ​​formed by the two measurement segments are subsequently erroneous. The averaging of multiple amplitude values, such as two or four amplitude values, then results in interference compensation.

[0015] In one embodiment of the stated method, the first and second sub-segments are sequentially connected, i.e., sequentially in time. Here, the second sub-segment can be directly connected to the first sub-segment or there can be a temporal interval between them. Alternatively, the first and second sub-segments can also partially overlap in time. For example, the first sub-segment can generally begin with the first measurement segment and end after 50% of its overall duration. To this end, for example, the second sub-segment can begin after 25% of the overall duration of the measurement segment and end after 75% of the overall duration of the measurement segment. Additionally, the first measurement segment can also have further sub-segments, i.e., a third, fourth, etc., sub-segments. By averaging the two sub-segments, interference present in the measurement segment can be easily identified. The average of shorter sub-segments can be reused to form the average of longer or other sub-segments. Here, interference of different frequencies and phases can be detected with relatively low computational cost.

[0016] Furthermore, an average value of the measurement signal can be formed for the first and second measurement value segments. Here, the average value is formed across the entire first or second measurement value segment. The first and second measurement value segments can be consecutive measurement value segments within the measurement signal. Accordingly, the first and second measurement value segments can have opposite amplitudes. For example, by forming a suitable difference between the average values ​​of the first and second measurement value segments, essentially double the amplitude of the measurement value, i.e., double the amplitude value, can be obtained. This provides an accurate value for the amplitude of the measurement signal with reduced computational costs.

[0017] If the summation of averages is alternatively performed as a replacement for the difference in formation, then a very small value is expected for the same time length in the measured value segment. Appropriate weighting is applied at different time lengths. If a very small value is not given during summation, then it is an indication of interference, such as a deviation of the magnetic flow rate from its normal value or electrochemical reactions of the electrodes. This can indicate damage or degradation of the components of the magnetic induction flowmeter.

[0018] In another embodiment of the stated method, the first and second steps are also performed accordingly for the second measurement value segment. Measurement signals are thus captured separately for the first and second measurement value segments and can be used further. Characteristic variables of the measurement value segment, such as the average value of the measurement signal, are modulated onto a carrier signal in time order, for example, by means of quadrature amplitude modulation. The carrier signal has a carrier frequency, which essentially corresponds to the pulse frequency, and is used to excite the magnetic coil. This allows the frequency offset relative to the comparison frequency to be obtained. When the measurement signal is free of interference, a spike, i.e., the maximum value, also called the peak value, is obtained in the frequency analysis, particularly by combining it with the comparison frequency. On the other hand, this combination can be constructed as so-called aliasing. When interference affecting the measurement signal is present, a spike is obtained in the described frequency analysis at the frequency corresponding to the frequency offset between the pulse frequency and the comparison frequency. This allows it to be determined whether the pulse frequency corresponds to a rated value. For example, when the pulse frequency is the frequency of the coupled network frequency, it can be determined whether the current network frequency, if associated with interference, corresponds to the power supply target frequency, particularly 50Hz or 60Hz. Interference present when measuring the flow rate in the tube can thus be further characterized and therefore appropriately compensated. Furthermore, the described steps can also be implemented for the third, fourth, and other measurement value sections.

[0019] In another embodiment of the stated method, the excitation of the magnetic coil can be interrupted for an adjustable duration in an additional step. This can be done by eliminating the presence of at least one pulse, or during the time interval between two excitations of the magnetic coil. Simultaneously, the remaining residual magnetic field in the tube is captured and further evaluated. Under the specified conditions, no usable or evaluable measurement signal is expected during the absence of excitation from the magnetic coil. Measurement signals received in the presence of interference correspond to interference, such as that generated by the magnetic field of a neighboring appliance. Such captured interference is ignored and / or suppressed during the evaluation of measurement signals in subsequent operation of the electromagnetic induction measuring device. Similarly, by evaluating the measurement signal of the residual magnetic field, the cause of interference, such as electromagnetic coupling in the magnetic coil circuitry, can be diagnosed. Overall, improved measurement accuracy and different self-diagnostic capabilities of the magnetic induction flowmeter can be achieved.

[0020] This objective is also achieved by the method described below according to the invention. It is based on the same specific mathematical and signal theory, as listed above. Therefore, the methods described above and those described below represent different aspects of the same technical solution and are connected to the same considerations and understandings essential to the invention.

[0021] The method according to the invention is used to measure the flow rate of a liquid in a pipe, to which a magnetic induction flowmeter is mounted. The magnetic induction flowmeter has a magnetic coil, through which a magnetic field is induced on the cross-section of the pipe, interacting with the flow-loaded particles in the pipe. This generates a voltage perpendicularly in the magnetic field on the cross-section of the pipe, which can be captured by a suitably mounted voltage sensor. In the first step of the method, the magnetic coil is excited using a rectangular signal with a pulse frequency. The rectangular signal, also called a box signal, can here be generated by the superposition of multiple sinusoidal signals. A voltage is generated on the cross-section of the pipe by the rectangular signal, which is captured as a measurement signal. The measurement signal is also substantially rectangular. The amplitude of the measurement signal corresponds to the flow rate to be measured in the pipe.

[0022] The method further includes a second step in which frequency analysis of the measurement signal is performed. Here, frequency analysis can be performed in parallel throughout the running time of the method. Frequency analysis can be performed on the measurement signal in time segments, which can overlap. The frequency components of the measurement signal are obtained through the frequency analysis in the second step. The frequency components are then considered in detail. In the third step, when the corresponding frequency component corresponds to an odd fraction of the pulse frequency, the frequency component is identified as a rectangular frequency component, i.e., generated by a rectangular signal on the magnetic coil. Furthermore, the present invention recognizes that the rectangular signal is formed as a combination of oscillations, the frequency of which corresponds, for example, to one, three, five, seven, etc., the pulse frequency. Therefore, the interference-free measurement signal in the frequency analysis only shows the predictable amplitude and phase described above. Furthermore, the combination of two overlapping rectangular signals between its measurement value segments can define an inactive phase. When the frequency portion of the measurement signal is not a rectangular frequency component, a fourth step is performed in the method according to the invention. Here, the corresponding frequency component of the measurement signal is identified as an interference frequency. The interference frequency is identified not only qualitatively but also quantitatively using the method according to the invention. This allows for the compensation of interference effects caused by interfering frequencies through appropriate filtering or correction measures. Frequency analysis can be performed quickly and allows for accurate evaluation of the measured signal. In such frequency analysis of the measured signal, its amplitude and phase values ​​can be derived algebraically, which allows for accurate evaluation of the measured signal. Accordingly, the method according to the invention is suitable for accurately deriving the amplitude value in the measured value segment, which allows for accurate calculation of the flow rate in the pipe despite the presence of interference. Additionally, the method according to the invention is suitable for identifying damage or degradation of the magnetic induction flowmeter in the frequency analysis of the measured signal, as degradation causes the results of the frequency analysis to deviate from the expected results. Furthermore, the method according to the invention is suitable for identifying different interferences and thus has improved durability. Therefore, the technological potential of the magnetic induction flowmeter is further exhausted. Rectangular signals are also understood to be such signals, which have predictable results in frequency analysis, in which the effects of interference that occur can be clearly identified.

[0023] According to the invention, the method includes the additional step of adjusting the duration of the measured value segment to an integer multiple of the period duration of the interference signal. For this purpose, the invention matches the duration of the inactive phase. Additionally, it is possible to match the pulse frequency.

[0024] In the implementation of the declared method, frequency analysis is constructed as Fourier analysis or wavelet analysis. It provides precise information about the characteristics of the measured signal as a whole and about selectable segments of the measured signal, particularly the measured value segments, which are susceptible to interference. Furthermore, Fourier classification and / or wavelet analysis are provided as functionalities that are efficiently executed in multiple signal processing chips or controllers. This also allows for greater full utilization of the technical potential of the magnetic induction flowmeter. Additionally, the declared method can be subsequently implemented on existing magnetic induction flowmeters with software or firmware upgrades. Accordingly, the declared method can effectively extend the technically reasonable service life of existing magnetic induction flowmeters. Alternatively, so-called least squares estimation can also be implemented as an alternative to frequency analysis, which can be implemented quickly with fewer measured signals.

[0025] Furthermore, in the fifth step of the declared method, the amplitude, or amplitude value, of the measured signal in at least the measured segment can be obtained through frequency analysis. For example, the amplitude corresponds to the sum of harmonious oscillations with alternating positive and negative signs in the measured signal in Fourier analysis. Such a sum can be obtained quickly with reduced computational cost. Intermediate results can then be applied during frequency analysis, thereby enabling rapid implementation of the declared method. In particular, due to the algebraic computational nature of the amplitude value, additional calculation steps, such as averaging, are essential.

[0026] Another embodiment of the stated method includes a further step in which the duration of the measured value segment is adjusted to an integer multiple of the period duration of the interference signal, i.e., the matching pulse frequency.

[0027] Therefore, in the implementation of forming the average value of the measured segment, interference with a periodicity having a corresponding periodic duration is suppressed. Through appropriate matching, frequencies of different and discordant applications can also be suppressed simultaneously.

[0028] The objective described at the outset is also achieved by a computer program product according to the invention, designed to drive a magnetic coil and process measurement signals from a voltage sensor. The computer program product provides a suitable interface for this purpose, allowing for the input and transmission of data or instructions accordingly. The magnetic coil and voltage sensor are, at least functionally, part of a magnetic induction flow meter. Furthermore, the computer program product is designed to determine, i.e., measure, the flow rate of the liquid at a cross-section of the tube of the flow meter. This is implemented in at least one embodiment of the method described above according to the invention. The computer program product can be implemented on a computing unit that works in conjunction with a storage unit. Furthermore, the computer program product can be designed monolithically, i.e., its full functionality can be implemented on a hardware platform. Alternatively, the computer program product can also be constructed as a system of at least two subroutines, which can be implemented on different hardware platforms and work together via a communicating data connection. Each subroutine includes at least one function of the computer program product, such as a predetermined parameter value for the magnetic induction flow meter. The functionality of the computer program product is achieved through their interaction. Such subroutines can be implemented, for example, on a control unit, control calculator, and / or computer cloud of the magnetic induction flow meter. Furthermore, computer program products can be constructed purely as software or with fixed wiring such as chips, integrated circuits, or FPGAs. Alternatively, computer program products can also be constructed as a combination of these.

[0029] Similarly, this objective is achieved by a control unit according to the invention. The control unit includes a storage unit and a computing unit, which interact during operation and allow the implementation of a computer program product. The control unit is designed to drive the magnetic induction flowmeter and provide suitable input and output of data or instructions to it. According to the invention, the control unit is designed to implement a computer program product according to one of the above embodiments. Alternatively, the control unit can implement at least one embodiment of the described method for conversion. Such a control unit can be implemented with simple hardware and is therefore particularly efficient. Thus, the technical advantages of this method are particularly easy to achieve.

[0030] Similarly, this objective is achieved by a magnetic induction flow meter according to the invention. The magnetic induction flow meter is designed to measure the flow rate of liquid across the cross-section of a pipe and provides an inductor coil and a voltage sensor for this purpose. The inductor coil and voltage sensor can be operated or read via a control unit. The control unit according to the invention is designed according to one of the above embodiments.

[0031] Furthermore, this objective is achieved by a computational program product according to the invention, which is suitable, in particular, for simulating the operating behavior of magnetic induction flowmeters.

[0032] Specifically, the computer program product can be configured to simulate the operating behavior of a magnetic induction flowmeter, wherein its structure is fixedly predetermined, i.e., its image is stored. Alternatively, the operating behavior can also be represented by a generalized computational model, which is independent of the spatial structure of the magnetic induction flowmeter. Furthermore, the operating behavior can also be derived from a combination thereof. The magnetic induction flowmeter to be simulated is according to a design of the above embodiment of the invention. The computer program product has a physical module in which the magnetic induction flowmeter is mapped, and the electrical or signal behavior of the magnetic induction flowmeter can be simulated under adjustable operating conditions. According to the invention, the adjustable operating conditions include interference spectra with different interference frequencies. For example, adjustable operating conditions may include: flow rate over the cross-sectional area of ​​the pipe, temperature, pressure, viscosity of the fluid in the pipe, its conductivity, its induction behavior, permeability, and magnetization capability. For this purpose, the computer program product can provide a data interface via which corresponding data related to user input and / or other simulation-related computer program products is predefined. The computer program product can also provide a data interface for outputting simulation results to the user and / or other simulation-related computer program products. The computer program product according to the present invention can be used to check the validity of the measurement signal of the voltage sensor of a magnetic induction flowmeter. The validity of sensor values ​​in other devices employing magnetic induction flowmeters can also be checked. Furthermore, damaged voltage sensors can be identified. Similarly, sensors showing signs of degradation can also be identified. Moreover, the present invention relates to sudden events, i.e., the above-described method is modeled with improved accuracy at a relatively low computational cost. Accordingly, the computer program product according to the present invention provides numerous feasible solutions for monitoring and / or testing corresponding magnetic induction flowmeters while simultaneously saving computational resources. The computer program product can be constructed as a so-called digital twin, as detailed in publication US 2017 / 286572 A1. This application references the disclosure of US 2017 / 286572A1. The computer program product is designed as a monolithic entity, i.e., it can be implemented entirely on a hardware platform. Alternatively, the computer program product can be modularly designed and include multiple subroutines, which can be implemented on separate hardware platforms and work together via a data connection. In particular, the computer program product can be designed for implementation in a computer cloud. Furthermore, the magnetic induction flowmeter can be simulated and / or optimized using the computer program product according to the invention, for example, during planned retrofits in equipment. Attached Figure Description

[0033] The present invention will now be described in detail with reference to the various embodiments shown in the accompanying drawings. Because the drawings are mutually complementary, the same reference numerals have the same technical meaning in different drawings. Features of the various embodiments can also be combined with each other. Furthermore, the embodiments shown in the drawings can be combined with the above-described features. These are shown here respectively: Figure 1 A schematic structure illustrating an embodiment of the claimed magnetic induction flowmeter is shown; Figure 2 A scenario illustrating a first embodiment of the method according to the present invention is shown; Figure 3 Show Figure 2 The next scenario for the method; Figure 4 Show Figure 3 Another scenario for the method; Figure 5 A schematic flow diagram of the second method according to the invention is shown. Detailed Implementation

[0034] Figure 1A schematic structure of an embodiment of the magnetic induction flowmeter 10 according to the present invention is shown. The magnetic induction flowmeter 10 is installed in a pipe 11 and is designed to measure the flow rate 15 through the pipe 11. For this purpose, the magnetic induction flowmeter 10 provides a magnetic coil 12, which can be excited via a control unit 30. The control unit 30 is designed to send an excitation signal in the form of a rectangular signal 21 to the magnetic coil 12 for excitation. The magnetic coil 12 generates a changing magnetic field 13 using a pulse frequency 19, which causes the charged particles 16 in the liquid 18 whose flow rate 15 is being measured to interact. The interaction between the charged particles 16 and the magnetic field 13 creates a voltage 17 substantially transverse to the magnetic field 13 that can be captured by a voltage sensor 14. The captured voltage 17 can be transmitted to the control unit 30 as a measurement signal 20. The excitation of the magnetic coil 12 is achieved by means of the rectangular signal 21, so that the magnetic field 13 has a predetermined magnetic flux density substantially immediately, which is maintained for a predetermined pulse duration and then returns to zero substantially immediately thereafter. This configuration of the rectangular signal 21 is also called a truck signal. Here, the excitation of the magnetic coil 12 is performed in the first steps 110 and 210 of methods 100 and 200, designed for measuring the flow rate 15. The capture of the voltage 17 by means of the voltage sensor 14 is performed in the second steps 120 and 220. The corresponding first steps 110 and 210 are identical in all methods 100 and 200 according to the invention. Methods 100 and 200, which can be implemented using the control unit 30, are based on the same considerations regarding the behavior of the captured measurement signal 20, which reflects the resulting voltage 17. The control unit 30 provides a storage unit 52 and a computing unit 54, through which a computer program product 50 can be implemented, via which at least one of methods 100 and 200 can be executed. Furthermore, the magnetic induction flowmeter 10 is mapped in the computer program product 80, constructed as a so-called digital twin. It is at least suitable for, and preferably designed for, simulating the operating behavior of the magnetic induction flowmeter 10 and includes for this purpose a structural mapping and / or mathematical model of the magnetic induction flowmeter 10 that reproduces its function. The computer program product 80 used to simulate operational behavior allows, for example, the identification of a damaged magnetic coil 12 or a damaged voltage sensor 14 and / or the verification of the resulting flow rate 15.

[0035] The first embodiment of the method 100 according to the present invention is in Figure 1 The scene is illustrated schematically. Figure 2 A graph showing the horizontal time axis 23 and the vertical voltage axis 25 as variable axes is presented. The graph shows the curve of the measured signal 20, corresponding to the voltage 17 captured via the voltage sensor 14, as shown. Figure 1 As shown. The measurement signal 20 corresponds to the rectangular signal 21 in its basic form, and utilizes it as follows: Figure 1The excitation magnetic coil 12 is shown. The measurement signal 20 includes measurement value segments 22, which follow each other in alternating orientations. An inactive phase 28 exists between the measurement value segments 22, the duration of which, i.e., its extension along the time axis 23, is configurable. The duration of the measurement value segments 22 and the inactive phase 28 together yield a periodic duration corresponding to a pulse frequency 19, which induces a changing magnetic field 13 in the tube 11 via the magnetic coil 12. Each measurement value segment 22 has an amplitude value 27 corresponding to a voltage 17, which is reproduced by the measurement signal 20. The amplitude value 27 corresponding to the current voltage 17 is interfered with in the measurement signal 20 by interference 29, which has an interference frequency 39. The consequence of interference 29 is weakened recognition of the correct amplitude value 27. Figure 2 The diagram reproduces the scenario of the first method 100, in which the first and second steps 110 and 120 have been implemented and the measurement signal 20 has been evaluated as much as possible. In order to evaluate the measurement signal 20 as much as possible, the various measurement value segments 22, especially the first measurement value segment and the second measurement value segments 24 and 26, are considered in detail. Figure 2 The scenario of method 100 shown is simulated in computer program product 80, which is constructed as a digital twin.

[0036] Figure 3 The first scenario of the method 100 according to the invention is shown, which is immediately followed by Figure 2 In the scene shown. Figure 3 It shows the basic Figure 2 A magnified view of the chart. Accordingly, Figure 3 The graph also has a time axis 23 and a voltage axis 25, showing the curve of the measured signal 20. In the third step 130, the first measured value segment 24 to be evaluated in detail is identified. The first measured value segment 24 can be easily identified in signal technology, for example, based on its substantially vertical front edge 36 or rear edge 34. In the third step 130, the first measured value segment 24 is divided into sub-segments 31, which are studied separately. The average value 37 of the measured signal 20 is obtained for the first sub-segment 32 of the first measured value segment 24 in the third step 130. Similarly, the average value 37 of the second sub-segment 33 of the first measured value segment 24 is obtained in the third step 130. The average value 37 is... Figure 3The second sub-segment 33 is directly implemented on the first sub-segment 32. Due to the substantially sinusoidal interference 29, the average value 37 of the measured signal 20, i.e., its corresponding average amplitude value 27, differs in the first and second sub-segments 32, 33. By comparing the average values ​​37 in the first and second sub-segments 32, 33, for example through appropriate difference formation, it can be concluded that interference 29 exists. Interference 29 is identified when the average values ​​37 in the first and second sub-segments 32, 33 deviate from each other by at least one interference threshold 38. The interference threshold 38 is predetermined by the user or by an algorithm that can be constructed as a component of the computer program product 50 in the control unit 30. Alternatively or additionally, other sub-segments 31 can also be selected as the first or second sub-segments 32, 33, which can also partially overlap in time. By repeating the third step 130 with different selected sub-segments 31 as the first sub-segment and the second sub-segment 32 of the first measurement segment 24, the form of the interference 29 can be determined in detail. Alternatively or additionally, the third step 130 can also be performed on the second measurement segment 26 accordingly. The formation of the average value 37 can be performed quickly in a simple manner and provides meaningful parameters for method 100. Figure 3 The scenario of method 100 shown is simulated in computer program product 80, which is constructed as a digital twin.

[0037] Another scenario of the first method 100 according to the present invention is... Figure 4 As shown in the image. Figure 4 The scenario begins here, where at least one of the first and second steps 110, 120 has ended and the fourth step 140 can be implemented. A carrier signal 45 is provided for the fourth step 140. The captured measurement signal 20, for example... Figure 2 The carrier signal 45 is combined with modulation 46 in the environment of at least the first measurement segment and the second measurement segments 24, 26. Modulation 46 is constructed as quadrature amplitude modulation. The resulting modulated carrier signal 35 is then subjected to frequency analysis 40 in the fourth step 140, the result of which is... Figure 4 The graph is shown below. It includes a horizontal frequency axis 41 and a vertical amplitude axis 43. Furthermore, the graph is separated by lines representing the so-called zero frequency, which is used as the comparison frequency 49. In the frequency analysis 40, a peak, also called a spike, is expected at the comparison frequency 49 in the measured signal 20 under interference-free or interference-suppressed conditions. Figure 4 In step 140 shown, frequency offset 47 and frequency offset quantization interference 29 are identified. The value of frequency offset 47, i.e., its distance from the comparison frequency 49, corresponds to, for example... Figure 2 or Figure 3The interference frequency 39 is shown. Furthermore, artifact 48 is identified in frequency analysis 40 to avoid confusion with interference frequency 39, i.e., interference 29. Artifact 48 can be predicted in the control unit 30 by computer program product 50 based on a combination of a given carrier frequency 53 and a given pulse frequency 19. This ensures, in a simple way, avoidance of diagnosed interference 29 that should not occur. The cause of interference 29 can be inferred from the interference 29 quantified via interference frequency 39 in the fourth step 140. Furthermore, the duration of the inactive phase 28 and / or the measured value segment 22 can be determined as follows: Figure 2 or Figure 3 The adaptation is performed as shown, thereby minimizing the impact of interference 29 on the resulting flow rate 15. For example... Figure 4 The method 100 shown allows for a reliable and sufficiently precise quantification of the disturbance 29, enabling the introduction of targeted countermeasures. Therefore, method 100 is self-adaptable and thus robust to the disturbance 29. Figure 4 The scenario of method 100 shown is simulated in computer program product 80, which is constructed as a digital twin.

[0038] An embodiment of the second method 200 for measuring flow rate 15 in tube 11 according to the present invention is as follows: Figure 5 The diagram is shown schematically. Method 200 proceeds from this, namely, the first step 210 as follows: Figure 2 As shown, this has been implemented. Accordingly, a measurement signal 20 exists from the first step 210, for which a frequency analysis 40 is performed in the second step 220. The frequency analysis 40 is here constructed as a Fourier analysis, through which the frequency components 42 of the measurement signal 20 are captured. The results of the frequency analysis 40 are... Figure 5 As shown in the diagram, it has a horizontal frequency axis 41 and a vertical amplitude axis 43. Frequency analysis 40 shows multiple frequency components 42, which capture the corresponding frequencies in the third step 230. A rectangular frequency component 44 is identified among the frequency components 42, that is, the actual frequency at the position of the corresponding peak 51 on the frequency axis 41, which substantially corresponds to an odd multiple of the pulse frequency 19. Using this, as... Figure 2The magnetic field 13 causing the change is shown. Method 200 is based on the fact that the rectangular signal 21 has only frequency component 42 in Fourier analysis, which corresponds to an odd multiple of the pulse frequency 19. Such frequency component 42 can then be reliably identified in method 200. The other frequency component 42 located between the rectangular frequency components 44 is identified as the interference frequency 39 in the fourth step 240. Here, the even-numbered harmony indicates nonlinearity, which is coupled to the pulse signal. For example, it can be a saturation effect in magnetic materials or electrochemical effects. Signal components with other frequencies can indicate external interference or damage in the electrical installation of the device. According to the third and fourth steps 230, the results of 240 can be identified in a simple way as which frequency component 42 of the measured signal 20 is used to determine the flow rate 15 in the pipe 11, such as Figure 1 As shown. For example, the interference frequency 39 identified in method 200 can be removed by means of a suitable filter. Alternatively or additionally, the amplitude value 27 can be derived from it as a rectangular frequency component 44, for example Figure 2 As shown. Frequency analysis 40, particularly Fourier analysis, can be performed quickly and accurately for the magnetic induction flowmeter 10 in multiple control units 30. This utilizes the increased available computing power of the control units 30 and allows for the application of the magnetic induction flowmeter 10 in harsh environments. Therefore, method 200 can be implemented in a device-dependent, i.e., decentralized manner. Consequently, the computational cost for flow measurement in the higher-order control systems of the automation system is reduced. This allows for the use of a large number of magnetic induction flowmeters 10 in automation systems without the risk of generating escalating inspection and calibration workloads in higher-level control systems where the flow rate 15 being measured has inappropriate values. Therefore, method 200 enables the magnetic induction flowmeter 10 to operate in a feasible manner in complex automation systems. Figure 5 The method 200 described therein can also be simulated in a computer program product 80 designed as a digital twin.

Claims

1. A method (100) for measuring flow (15) in a tube (11) by means of a magnetic induction flow meter (10), the magnetic induction flow meter being fastened to the tube (11), the method comprising the steps of: a) The magnetic coil (12) of the magnetic induction flowmeter (10) is excited at a pulse frequency (19) using a rectangular signal (21) and the measurement signal (20) is captured. b) Capture a first measurement segment (24) of the measurement signal (20), the first measurement segment including a first sub-segment and a second sub-segment (32, 33); c) The average value (37) of the measurement signal (20) in the first sub-segment and the second sub-segment (32, 33) is obtained respectively. When the average values ​​(37) deviate from each other by at least an adjustable interference threshold (38), interference (29) in the measurement signal (20) is identified. The rectangular signal (21) is characterized by having an inactive phase (28) that can be adjusted independently of the first measurement segment and / or the second measurement segment (24, 26), and in another step, the pulse duration of the rectangular signal (21) and / or the duration of the inactive phase (28) are adapted to balance the interference effect in the consecutive measurement segments (22, 24, 26).

2. The method (100) according to claim 1, characterized in that, The first sub-segment and the second sub-segment (32, 33) follow each other in time or partially overlap in time.

3. The method (100) according to claim 1 or 2, characterized in that, The average value (37) of the measurement signal (20) is obtained for the first measurement value segment (24) and the second measurement value segment (26), and the amplitude (27) of the measurement signal (20) is obtained based on this.

4. The method (100) according to claim 1 or 2, characterized in that, At least steps a) and b) are also implemented for the second measurement segment (26), wherein the measurement signal (20) of the first measurement segment and the second measurement segment (24, 26) is modulated onto a carrier signal (45), the carrier frequency (53) of the carrier signal corresponding to the pulse frequency (19), and thus a frequency offset (47) relative to the comparison frequency (49) is obtained.

5. The method (100) according to claim 4, characterized in that, The carrier signal (45) is modulated by means of quadrature amplitude modulation, and / or the comparison frequency (49) is the power supply target frequency.

6. A method (200) for measuring flow rate (15) in a tube (11) by means of a magnetic induction flow meter (10), the magnetic induction flow meter being fastened to the tube (11), the method comprising the steps of: a) The magnetic coil (12) of the magnetic induction flowmeter (10) is excited at a pulse frequency (19) using a rectangular signal (21) and the measurement signal (20) is captured. b) To obtain the frequency components (42) of the measurement signal (20), a frequency analysis (40) of the measurement signal (20) is performed; c) When the frequency component (42) corresponds to an odd fraction of the pulse frequency (19), the frequency component (42) of the measurement signal (20) is identified as a rectangular frequency component (44); and otherwise, d) Identify the frequency component of the measurement signal (20) as an interference frequency (39); Its features are, In another step, the duration of the measured value segment (22) of the measured signal (20) is modified to an integer multiple of the period duration of the interference frequency (39), wherein the duration of the inactive phase (28) is adapted to minimize the interference effect for deriving the flow rate.

7. The method (200) according to claim 6, characterized in that, The frequency analysis (40) is designed as either Fourier analysis or wavelet analysis.

8. The method (200) according to claim 6 or 7, characterized in that, Another step e) is performed, wherein the amplitude (27) of the measured signal (20) is obtained based on the frequency analysis (40).

9. A control unit (30) for a magnetic induction flowmeter (10), the control unit comprising a storage unit (52) and a computing unit (54) for executing a computer program product (50), characterized in that, The control unit (30) is designed to implement at least one method according to any one of claims 1 to 8.

10. A magnetic induction flowmeter (10) for measuring flow rate (15) through a pipe (11), the magnetic induction flowmeter comprising a magnetic coil (12) and a voltage sensor (14) connected to a control unit (30), characterized in that, The control unit (30) is designed according to claim 9.

11. A computer program product (80) designed to simulate the operating behavior of a magnetic induction flowmeter (10), characterized in that, The flow meter (10) is designed according to claim 10, and the computer program product (80) is designed as a digital twin, wherein the computer program product (80) has a physical module in which the magnetic induction flow meter (10) is mapped and the electrical or signal behavior of the magnetic induction flow meter can be simulated under adjustable operating conditions, wherein the adjustable operating conditions include an interference spectrum with different interference frequencies, and the computer program product (80) is designed to check the validity of the measurement signal of the voltage sensor of the magnetic induction flow meter (10) in order to identify a damaged voltage sensor.

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