CN117268483B - Instantaneous flow metering method suitable for ultrasonic water meter - Google Patents
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F15/00—Details of, or accessories for, apparatus of groups G01F1/00 - G01F13/00 insofar as such details or appliances are not adapted to particular types of such apparatus
- G01F15/02—Compensating or correcting for variations in pressure, density or temperature
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
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Abstract
The invention relates to the technical field of flow calculation, and discloses an instantaneous flow metering method suitable for an ultrasonic water meter, which comprises the following steps: measuring the resonance frequency of the water meter, and calculating the difference between the resonance frequency and the excitation frequency; collecting signals received by upstream and downstream transducers of the water meter; extracting an envelope signal to perform three-point correlation calculation and interpolating to calculate the maximum position; performing cross-correlation calculation on the acquired signals; taking a module after FFT of a calculation result; interpolation operation is carried out on the modulus result; calculating peak width ratio and signal to noise ratio of interpolation operation result; calculating a threshold value; and executing the subsequent process according to the comparison result of the peak width ratio and the threshold value. According to the invention, the related calculation range is roughly positioned through the envelope characteristics, so that the calculation efficiency is improved. The threshold value is defined by the frequency difference and the signal to noise ratio, and the frequency domain characteristics of the correlation result of the received signal are adaptively adjusted and calculated, so that the problem that the correlation calculation result and the true value have larger deviation after the signal to noise ratio is reduced due to noise increase, energy converter aging, flow overload and the like is solved, and the accuracy and the operation reliability of the water meter are ensured.
Description
Technical Field
The invention relates to the technical field of flow calculation, in particular to an instantaneous flow metering method suitable for an ultrasonic water meter.
Background
The ultrasonic water meter is widely applied in civil and industrial fields due to the advantages of high metering precision, wide measuring range ratio, small pressure loss and the like, and calculates the flow velocity through the propagation time difference of ultrasonic signals received by the upstream transducer and the downstream transducer. The correlation method is to obtain the time difference of two paths of signals according to the similarity, is insensitive to the signal amplitude, and can be used for flow calculation of an ultrasonic water meter. However, due to environmental noise change, or aging of the transducer, overload of flow and the like, after the signal to noise ratio of the system is reduced, deviation of + -1 cycle exists between the calculated time difference and the true value of the correlation method, and no effective filtering means exists, so that the calculated flow value is seriously deviated, and a larger metering error is caused.
Disclosure of Invention
Aiming at the defects and drawbacks existing in the prior art, the invention provides an instantaneous flow metering method suitable for an ultrasonic water meter, which solves the problems of large time difference and true value deviation calculated by a correlation method after the signal to noise ratio of a system is reduced due to environmental noise change, transducer aging and the like, and accurately meters flow, thereby realizing high precision and high reliability of the ultrasonic water meter.
The object of the invention can be achieved by the following technical scheme.
An instantaneous flow metering method suitable for an ultrasonic water meter comprises the following steps.
S1, measuring the resonant frequency of an ultrasonic water meter, and calculating the resonant frequency and the excitation frequency f 0 A difference Δf.
S2, collecting signals received by an upstream transducer and a downstream transducer of the ultrasonic water meter, and respectively marking the signals as X and Y.
S3, respectively extractingEnvelope signal X of X and Y 0 And Y 0 Performing three-point correlation calculation, and interpolating to calculate the maximum value position P of the three-point correlation calculation result 0 。
S4, according to window Width, P 0 And performing cross-correlation calculation on X and Y.
S5, calculating a result R of the cross-correlation xy Taking the modulus after FFT to obtain r xy 。
For r xy And performing interpolation operation.
The peak-to-width ratio PWR and the signal-to-noise ratio SNR of the interpolation operation result are calculated.
S6, calculating a threshold value Thres, wherein the calculation formula is as follows.
；
SNR in ideal PWR is an ideal value for signal-to-noise ratio SNR ideal Is the ideal value of the peak width ratio PWR, and Δf is the resonant frequency and the excitation frequency f 0 And lambda is an adjustable parameter.
S7, comparing the PWR with the Thres, and executing the subsequent process according to the comparison result.
If PWR is less than or equal to Thres, setting the window width to be 2, starting a signal acquisition optimization function, and then jumping to S2; if the PWR is less than or equal to Thres in three continuous comparisons, the process is terminated and an alarm is given.
If PWR > Thres, for R xy Performing interpolation calculation; obtaining a time difference delta T according to the interpolation calculation result and setting the window width to be 1; the instantaneous flow is calculated from deltat and temperature compensated.
Preferably, the window Width default value is 2, and the ultrasonic water meter signal acquisition optimization function is closed by default.
The signal acquisition optimization function comprises the steps of increasing the gain of an amplifier, increasing a filtering function and increasing the transmitting power.
Preferably, the method for extracting the envelope signal in step S3 includes a hilbert transform method and a maxima method.
If the hilbert transform method is adopted, downsampling is needed to be carried out on the extracted envelope signal, and the downsampling rate M is the ratio of the sampling rate to the excitation frequency.
Preferably, the three-point correlation calculation formula in the step S3 is as follows。
Wherein R is xy,0 For three-point correlation calculation result, N is envelope signal X 0 And Y 0 Is used for the signal length of the (c).
Interpolation calculation methods include parabolic interpolation, cosine interpolation, gaussian interpolation, and cubic spline interpolation.
Preferably, the cross-correlation calculation formula in the step S4 is。
Where Len is the signal length of the signals X and Y received by the upstream and downstream transducers, and M is the ratio of the sampling rate to the excitation frequency.
Preferably, the peak width ratio PWR calculation formula in the step S5 is。
Wherein Peak is the number of pairs r xy Peak value calculated after interpolation, FHWM is given to r xy The half-width calculated after interpolation.
The beneficial technical effects of the invention are as follows: and the related calculation range is roughly positioned through the extracted envelope features, so that the operation efficiency is improved. The frequency difference and the signal to noise ratio are used for defining a threshold value, the frequency domain characteristics of the result after the signal correlation are received by the upstream transducer and the downstream transducer, and the self-adaptive adjustment and calculation process are adopted, so that the problem that the calculation result and the true value of the correlation method have larger deviation after the signal to noise ratio of the system is reduced due to the increase of environmental noise, the aging of the transducer or the overload of the flow is solved, the accuracy of the ultrasonic water meter is ensured, and the operation reliability of the ultrasonic water meter is improved.
Drawings
Fig. 1 is a general flow chart of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Examples: as shown in fig. 1, a method for measuring an instantaneous flow rate suitable for an ultrasonic water meter includes the following steps.
S1, measuring the resonant frequency of an ultrasonic water meter, and calculating the resonant frequency and the excitation frequency f 0 The difference Deltaf, taking a certain type of ultrasonic water meter as an example, the excitation frequency f 0 The measured resonance frequency was 1.94 MHz and the frequency difference Δf was 0.06 MHz at 2.00 MHz.
S2, sampling rate f s The sampling window is 30 us, the upstream and downstream transducers of the ultrasonic water meter are used for collecting the receiving signals, which are respectively marked as X and Y, and the signal length is 240.
S3, extracting envelope signals X of X and Y respectively 0 And Y 0 The method for extracting the envelope signal comprises a Hilbert transform method and a maximum value solving method, wherein the Hilbert transform method is adopted to extract the envelope, the envelope output by the Hilbert transform is downsampled, and the sampling rate M is higher than the original sampling rate f s Reduced by 4 times.
And then three-point correlation calculation is carried out, wherein the calculation formula is as follows。
In the method, in the process of the invention,for the three-point correlation calculation result, N is equal to 60, which is the envelope signal X 0 And Y 0 Is used for the signal length of the (c).
Then calculating the maximum value position P of the three-point correlation result by interpolation 0 The interpolation calculation method comprises parabolic interpolation, cosine interpolation, gaussian interpolation and cubic spline interpolation, cosine interpolation is selected in the embodiment, and the maximum value position P of the three-point correlation result is calculated 0 0.18.
S4, according to window Width, P 0 Performing cross-correlation calculation on the received signals X and Y of the upstream and downstream transducers to obtain a cross-correlation result R xy ：。
In the method, in the process of the invention,receiving cross-correlation results of signals X and Y for upstream and downstream transducers; len is equal to 240, the signal length for the upstream and downstream transducers to receive signals X and Y; p (P) 0 Equal to 0.18, envelope signal X 0 And Y 0 The maximum value position of the result after three-point correlation; m is equal to 4, which is the sampling rate f s And excitation frequency f 0 Is a ratio of (2); width is equal to 2, which is the window Width.
In the present embodiment, it is calculated thatSince m can only be an integer, the range of values is rounded to [ -4,5]。
S5, for the cross-correlation result R xy After FFT, taking the modulus to obtain r xy Calculating peak width ratio and signal to noise ratio of interpolation operation result, wherein the peak width ratio。
Wherein Peak is the number of pairs r xy Peak value calculated after interpolation, FHWM is given to r xy The half-width calculated after interpolation.
In this embodiment, the peak width ratio is calculated to be 49.19, and the signal to noise ratio is the average value of the signal to noise ratios of the signals received by the upstream and downstream transducers, which is 38.87 dB.
S6, calculating a threshold value。
In the SNR ideal PWR is an ideal value of signal-to-noise ratio SNR and is related to the design range ratio and the precision level of the ultrasonic water meter ideal For an ideal value of the peak-to-width ratio PWR, Δf is the resonant frequency and the excitation frequency f, depending on the transducer design 0 And lambda is an adjustable parameter. In this embodiment, the signal-to-noise ratio is an ideal value SNR ideal Ideal value PWR for peak width ratio of 50 dB ideal 24.00, according to the ultrasonic water meter of a certain model, lambda takes a value of 0.65, and the threshold value Thres is calculated to be 12.38.
S7, comparing the PWR with the Thres, and executing the subsequent process according to the comparison result.
If PWR is less than or equal to Thres, setting the window width to be 2, starting a signal acquisition optimization function, then jumping to S2, firstly increasing the gain and the transmitting power of an amplifier, then acquiring again, firstly filtering the acquired signals received by the upstream transducer and the downstream transducer, and then executing the steps S3-S7; if the PWR is not more than Thres after three continuous acquisitions, the process is terminated and an alarm is given.
If the peak width ratio is greater than the threshold value, for R xy Performing interpolation calculation, and finally obtaining a time difference delta T and setting the window width to be 1; the instantaneous flow is calculated from deltat and temperature compensated.
The window Width default value is 2, and the ultrasonic water meter signal acquisition optimization function is closed by default; the ultrasonic water meter signal acquisition optimization function comprises the steps of increasing the gain of an amplifier, increasing a filter function and increasing the transmitting power.
The above embodiments are illustrative of the specific embodiments of the present invention, and not restrictive, and various changes and modifications may be made by those skilled in the relevant art without departing from the spirit and scope of the invention, so that all such equivalent embodiments are intended to be within the scope of the invention.
Claims (6)
1. An instantaneous flow metering method suitable for an ultrasonic water meter is characterized by comprising the following steps:
s1, measuring the resonant frequency of an ultrasonic water meter, and calculating the resonant frequency and the excitation frequency f 0 A difference Δf;
s2, collecting signals received by an upstream transducer and a downstream transducer of the ultrasonic water meter, and respectively marking the signals as X and Y;
s3, extracting envelope signals X of X and Y respectively 0 And Y 0 Performing three-point correlation calculation, and interpolating to calculate the maximum value position P of the three-point correlation calculation result 0 ；
S4, according to window Width, P 0 For X andy performs cross-correlation calculation;
s5, calculating a result R of the cross-correlation xy Taking the modulus after FFT to obtain r xy ；
For r xy Performing interpolation operation;
calculating a peak width ratio PWR and a signal to noise ratio SNR of an interpolation operation result;
s6, calculating a threshold value Thres, wherein the calculation formula is as follows:
；
SNR in ideal PWR is an ideal value for signal-to-noise ratio SNR ideal Is the ideal value of the peak width ratio PWR, and Δf is the resonant frequency and the excitation frequency f 0 The difference, λ, is an adjustable parameter;
s7, comparing the PWR with the Thres, and executing the following procedures according to the comparison result:
if PWR is less than or equal to Thres, setting the window width to be 2, starting a signal acquisition optimization function, and then jumping to S2; if the PWR is less than or equal to Thres in three continuous comparisons, terminating the flow and alarming;
if PWR > Thres, for R xy Performing interpolation calculation; obtaining a time difference delta T according to the interpolation calculation result and setting the window width to be 1; the instantaneous flow is calculated from deltat and temperature compensated.
2. The instantaneous flow metering method suitable for the ultrasonic water meter according to claim 1, wherein the window Width default value is 2, and the ultrasonic water meter signal acquisition optimization function is closed by default;
the signal acquisition optimization function comprises the steps of increasing the gain of an amplifier, increasing a filtering function and increasing the transmitting power.
3. The method for measuring instantaneous flow rate of ultrasonic water meter according to claim 1, wherein the method for extracting envelope signal in step S3 comprises hilbert transform method and maximum value method;
if the hilbert transform method is adopted, downsampling is needed to be carried out on the extracted envelope signal, and the downsampling rate M is the ratio of the sampling rate to the excitation frequency.
4. The method for measuring instantaneous flow rate of ultrasonic water meter according to claim 1, wherein the three-point correlation calculation formula in step S3 is；
Wherein R is xy,0 For three-point correlation calculation result, N is envelope signal X 0 And Y 0 Is a signal length of (a);
interpolation calculation methods include parabolic interpolation, cosine interpolation, gaussian interpolation, and cubic spline interpolation.
5. The method for measuring instantaneous flow rate of ultrasonic water meter according to claim 1, wherein the cross-correlation calculation formula in step S4 is；
Where Len is the signal length of the signals X and Y received by the upstream and downstream transducers, and M is the ratio of the sampling rate to the excitation frequency.
6. The method according to claim 1, wherein the peak-to-width ratio PWR calculation formula in step S5 is；
Wherein Peak is the number of pairs r xy Peak value calculated after interpolation, FHWM is given to r xy The half-width calculated after interpolation.
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Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013079074A1 (en) * | 2011-12-02 | 2013-06-06 | Kamstrup A/S | Ultrasonic flow meter with digitally under-sampled flow measurements |
| US9383239B2 (en) * | 2010-04-28 | 2016-07-05 | Apator Miitors Aps | Ultrasonic flow meter with subsampling of ultrasonic transducer signals |
| WO2016150385A1 (en) * | 2015-03-24 | 2016-09-29 | 合肥工业大学 | Fpga- and dsp-based gas ultrasonic flowmeter and metering method therefor |
| CN106546818A (en) * | 2016-10-20 | 2017-03-29 | 南京航空航天大学 | A kind of harmonic signal detection method based on DNL Mode Decomposition |
| CN113124948A (en) * | 2021-05-20 | 2021-07-16 | 中国计量大学 | High-precision time difference measuring method based on FPGA and cross-correlation method |
| CN114397475A (en) * | 2022-03-25 | 2022-04-26 | 青岛鼎信通讯股份有限公司 | Water flow velocity measuring method suitable for ultrasonic water meter |
| CN115773793A (en) * | 2022-11-29 | 2023-03-10 | 青岛鼎信通讯科技有限公司 | Ultrasonic water meter signal amplitude dynamic adjustment method |
| CN115824331A (en) * | 2023-02-22 | 2023-03-21 | 青岛鼎信通讯科技有限公司 | Low-power consumption measuring method suitable for ultrasonic water meter |
| CN115900899A (en) * | 2022-12-08 | 2023-04-04 | 青岛鼎信通讯科技有限公司 | Ultrasonic water meter metering error correction method |
| CN116625444A (en) * | 2023-03-13 | 2023-08-22 | 宁夏隆基宁光仪表股份有限公司 | Method for self-adapting characteristic wave and flow correction of ultrasonic water meter |
| CN116878599A (en) * | 2023-09-06 | 2023-10-13 | 青岛鼎信通讯科技有限公司 | Flow metering method of ultrasonic water meter |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102022100677A1 (en) * | 2022-01-12 | 2023-07-13 | Diehl Metering Gmbh | Method and measuring device for determining a measured variable relating to a flow |
-
2023
- 2023-11-23 CN CN202311566497.9A patent/CN117268483B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9383239B2 (en) * | 2010-04-28 | 2016-07-05 | Apator Miitors Aps | Ultrasonic flow meter with subsampling of ultrasonic transducer signals |
| WO2013079074A1 (en) * | 2011-12-02 | 2013-06-06 | Kamstrup A/S | Ultrasonic flow meter with digitally under-sampled flow measurements |
| WO2016150385A1 (en) * | 2015-03-24 | 2016-09-29 | 合肥工业大学 | Fpga- and dsp-based gas ultrasonic flowmeter and metering method therefor |
| CN106546818A (en) * | 2016-10-20 | 2017-03-29 | 南京航空航天大学 | A kind of harmonic signal detection method based on DNL Mode Decomposition |
| CN113124948A (en) * | 2021-05-20 | 2021-07-16 | 中国计量大学 | High-precision time difference measuring method based on FPGA and cross-correlation method |
| CN114397475A (en) * | 2022-03-25 | 2022-04-26 | 青岛鼎信通讯股份有限公司 | Water flow velocity measuring method suitable for ultrasonic water meter |
| CN115773793A (en) * | 2022-11-29 | 2023-03-10 | 青岛鼎信通讯科技有限公司 | Ultrasonic water meter signal amplitude dynamic adjustment method |
| CN115900899A (en) * | 2022-12-08 | 2023-04-04 | 青岛鼎信通讯科技有限公司 | Ultrasonic water meter metering error correction method |
| CN115824331A (en) * | 2023-02-22 | 2023-03-21 | 青岛鼎信通讯科技有限公司 | Low-power consumption measuring method suitable for ultrasonic water meter |
| CN116625444A (en) * | 2023-03-13 | 2023-08-22 | 宁夏隆基宁光仪表股份有限公司 | Method for self-adapting characteristic wave and flow correction of ultrasonic water meter |
| CN116878599A (en) * | 2023-09-06 | 2023-10-13 | 青岛鼎信通讯科技有限公司 | Flow metering method of ultrasonic water meter |
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