An anti-error wave method for an ultrasonic flowmeter and an ultrasonic flowmeter

Abstract

The present application discloses an anti-false wave method for an ultrasonic flowmeter and an ultrasonic flowmeter. The method includes: setting an initial threshold; obtaining, according to the initial threshold, the peak value of the steady-state sine wave and the amplitudes of a plurality of consecutive waveforms that exceed the initial threshold and are before the steady-state sine wave from the first echo signal, including: the first wave and the adjacent waveforms after the first wave; calculating a first preset value according to the peak value of the steady-state sine wave of the first echo signal and the amplitudes of the plurality of waveforms; obtaining a second preset value of the second echo signal according to the initial threshold; obtaining a second threshold according to the ratio of the second preset value to the first preset value; obtaining the first wave of the third echo signal according to the second threshold. By calculating the ratio of the first preset value of the first echo signal to the second preset value of the second echo signal, and adjusting the initial threshold according to the ratio to obtain the second threshold, the logic is simple, which is conducive to real-time calculation, can avoid the influence of false waves, reduce the influence of interference on the measurement result, and improve the measurement accuracy.

Description

Technical Field

[0001] The present application relates to the technical field of ultrasonic instruments, and in particular to an anti-error wave method for an ultrasonic flowmeter and an ultrasonic flowmeter. Background Art

[0002] In recent years, with the advancement of science and technology, smart water meters have developed rapidly. Ultrasonic flow meters have been increasingly used in the field of flow detection due to their advantages such as large range ratio, small starting flow, low pressure loss, and bidirectional measurement. Ultrasonic flow meters generally use the time difference method for measurement. The time difference method is a measurement method that calculates flow information based on the propagation time difference of ultrasonic waves in the measured medium in both upstream and downstream conditions. At present, in the time difference method, it is generally adopted to obtain accurate upstream and downstream flight time by setting a threshold. In the actual application scenarios of ultrasonic flow meters, there will be more interference, such as scaling on the transducer surface, more impurities, environmental noise, etc. The emergence of these common and unavoidable interferences will cause changes in the transducer receiving signal, resulting in the set threshold not meeting the measurement requirements and causing the occurrence of wrong waves.

[0003] In conventional ultrasonic measurement algorithms, the method usually adopted is to abandon the value of the wrong wave in this measurement and use the last measurement value instead. However, if the wrong wave situation continues to occur, the last value is always used as the measurement value, which will cause measurement errors and affect the accuracy of the measurement. Therefore, this method can only compensate for a short time and cannot guarantee its measurement accuracy, and it cannot solve the problem of wrong wave in principle.

[0004] In summary, it is necessary to provide an anti-error wave method and an ultrasonic flow meter for an ultrasonic flow meter, which can avoid the influence of error waves, reduce the influence of interference on metering results, and improve metering accuracy. Summary of the invention

[0005] In order to solve the above problems, the present application proposes an anti-error wave method for an ultrasonic flow meter and an ultrasonic flow meter.

[0006] On the one hand, the present application proposes a method for preventing wrong waves for an ultrasonic flow meter, comprising:

[0007] Set the initial threshold;

[0008] According to the initial threshold, obtaining from the first echo signal a peak value of a steady-state sine wave and amplitudes of a plurality of continuous waveforms exceeding the initial threshold and preceding the steady-state sine wave, the plurality of continuous waveforms comprising: a first wave and adjacent waveforms after the first wave;

[0009] Calculate and obtain a first preset value according to the peak value of the steady-state sinusoidal wave of the first echo signal and the amplitudes of the multiple waveforms;

[0010] Obtain a second preset value of the second echo signal according to the initial threshold;

[0011] Obtain a second threshold according to the ratio of the second preset value to the first preset value;

[0012] Obtain the first wave of the third echo signal according to the second threshold.

[0013] Preferably, after obtaining the first wave of the third echo signal according to the second threshold, it further includes:

[0014] Obtain a new echo signal and update the second preset value according to the second threshold;

[0015] Update the second threshold according to the ratio of the updated second preset value to the first preset value.

[0016] Preferably, the setting of the initial threshold includes:

[0017] Obtain a first echo signal;

[0018] Determine the maximum amplitude of the first echo signal;

[0019] Calculate the initial threshold according to the maximum amplitude and the peak average value of the two sine waves with the largest peak difference in the first echo signal.

[0020] Preferably, the calculating the initial threshold according to the maximum amplitude and the peak average value of the two sine waves with the largest peak difference in the first echo signal includes:

[0021] Normalize the obtained first echo signal;

[0022] Compare the peaks of each sine wave in the normalized first echo signal and obtain the two sine waves with the largest peak difference;

[0023] Calculate the peak average value of the two sine waves with the largest peak difference;

[0024] Multiply the peak average value by the maximum amplitude of the first echo signal to obtain the initial threshold.

[0025] Preferably, the calculating the first preset value according to the peak value of the steady-state sine wave of the first echo signal and the amplitudes of the multiple waveforms includes:

[0026] Square the peak value of the first wave, the peak values of the two adjacent waveforms after the first wave, and the peak value of the steady-state sine wave in the first echo signal respectively to obtain the energy peak value of the first wave, the energy peak values of the two adjacent waveforms after the first wave, and the energy peak value of the steady-state sine wave in the first echo signal;

[0027] Normalize the energy peak of the steady-state sine wave in the first echo signal with respect to the energy peak of the first wave of the first echo signal and the energy peaks of two adjacent waveforms after the first wave respectively, to obtain the first normalization value of the first wave of the first echo signal, the first normalization value of the first-first wave, and the first normalization value of the first-second wave;

[0028] Calculate the sum of the first normalization value of the first wave of the first echo signal, the first normalization value of the first-first wave, and the first normalization value of the first-second wave, to obtain the first normalization value sum, which is used as the first preset value.

[0029] Preferably, obtaining the second preset value of the second echo signal according to the initial threshold includes:

[0030] Determine the first wave, the first-first wave, and the first-second wave from the second echo signal according to the initial threshold;

[0031] Determine the peak value of the steady-state sine wave when the second echo signal reaches a steady state;

[0032] Square the peak value of the first wave, the peak value of the first-first wave, the peak value of the first-second wave, and the peak value of the steady-state sine wave in the second echo signal respectively, to obtain the energy peak of the first wave, the energy peak of the first-first wave, the energy peak of the first-second wave, and the energy peak of the steady-state sine wave in the second echo signal;

[0033] Normalize the energy peak of the steady-state sine wave in the echo signal to be measured with respect to the energy peak of the first wave, the energy peak of the first-first wave, and the energy peak of the first-second wave of the echo signal to be measured respectively, to obtain the second normalization value of the first wave, the second normalization value of the first-first wave, and the second normalization value of the first-second wave of the echo signal to be measured;

[0034] Calculate the sum of the second normalization values of the first wave, the first-first wave, and the first-second wave of the echo signal to be measured, and use it as the second preset value.

[0035] Preferably, obtaining the second threshold according to the ratio of the second preset value to the first preset value includes:

[0036] Divide the second preset value by the first preset value to obtain the normalization ratio;

[0037] If the normalization ratio is less than the first limit value, the second threshold is equal to the initial threshold plus one;

[0038] If the normalization ratio is greater than the second limit value, the second threshold is equal to the initial threshold minus one;

[0039] If the normalized quantity ratio is within the range greater than or equal to the first limit value and less than or equal to the second limit value, the initial threshold is adjusted according to the first wave pulse width of the first echo signal to obtain a second threshold.

[0040] Preferably, the first wave is a sine wave when the amplitude of the echo signal first reaches the threshold;

[0041] The first subsequent wave is the first sine wave after the first wave;

[0042] The second subsequent wave is the second sine wave after the first wave.

[0043] In a second aspect, the present application provides an ultrasonic flowmeter, and the ultrasonic flowmeter uses the above anti-miswave method for ultrasonic flowmeters to determine the second threshold.

[0044] The advantages of the present application are as follows: By calculating the peak value of the steady-state sine wave of the first echo signal and the amplitudes of multiple waveforms exceeding the initial threshold, a first preset value is obtained, and then a second preset value of the second echo signal is obtained according to the initial threshold, and the second threshold is determined. The first wave of the third echo signal is obtained according to the second threshold to prevent miswaves. The logic is simple, which is conducive to real-time calculation, can avoid the influence of miswaves, reduce the influence of interference on the measurement result, and improve the measurement accuracy. Description of the Drawings

[0045] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0046] Figure 1 is a schematic diagram of the steps of an anti-miswave method for an ultrasonic flowmeter provided by the present application;

[0047] Figure 2 is a schematic flowchart of an anti-miswave method for an ultrasonic flowmeter provided by the present application;

[0048] Figure 3 is a schematic diagram of a sine wave of an anti-miswave method for an ultrasonic flowmeter provided by the present application. Detailed Embodiments

[0049] Hereinafter, the exemplary embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0050] In a first aspect, according to an embodiment of the present application, a method for preventing false waves in an ultrasonic flowmeter is proposed, as Figure 1 shown, including:

[0051] S101, set an initial threshold;

[0052] S102, according to the initial threshold, obtain the peak value of the steady-state sine wave and the amplitudes of multiple consecutive waveforms that exceed the initial threshold and are before the steady-state sine wave from the first echo signal, where the multiple consecutive waveforms include: the first wave and the adjacent waveforms after the first wave;

[0053] S103, calculate and obtain a first preset value according to the peak value of the steady-state sine wave of the first echo signal and the amplitudes of multiple waveforms;

[0054] S104, obtain a second preset value of the second echo signal according to the initial threshold;

[0055] S105, obtain a second threshold according to the ratio of the second preset value to the first preset value;

[0056] S106, obtain the first wave of the third echo signal according to the second threshold.

[0057] After obtaining the first wave of the third echo signal according to the second threshold, it further includes: obtaining a new echo signal, updating the second preset value according to the second threshold; updating the second threshold according to the ratio of the updated second preset value to the first preset value.

[0058] Setting the initial threshold includes:

[0059] Obtain the first echo signal; determine the maximum amplitude of the first echo signal; calculate the initial threshold according to the maximum amplitude and the average value of the peak values of the two sine waves with the largest peak difference in the first echo signal.

[0060] Calculating the initial threshold according to the maximum amplitude and the average value of the peak values of the two sine waves with the largest peak difference in the first echo signal includes: normalizing the obtained first echo signal; comparing the peak values of each sine wave in the normalized first echo signal to obtain the two sine waves with the largest peak difference; calculating the average value of the peak values of the two sine waves with the largest peak difference; multiplying the average value of the peak values by the maximum amplitude of the first echo signal to obtain the initial threshold.

[0061] Obtain the steady-state sine wave peak value and the amplitudes of multiple waveforms exceeding the initial threshold from the first echo signal according to the initial threshold, including: determining, according to the initial threshold, the first wave, the first adjacent wave, and the second adjacent wave that exceed the initial threshold and are before the steady-state sine wave from the first echo signal; determining the steady-state sine wave peak value when the first echo signal reaches the steady state. Wherein, the first adjacent wave and the second adjacent wave are adjacent waveforms after the first wave, that is, the first wave, the first adjacent wave, and the second adjacent wave are three adjacent waveforms in sequence. Preferably, the number of multiple consecutive waveforms is 3, that is, the first wave, the first adjacent wave, and the second adjacent wave. The number of multiple consecutive waveforms can also exceed 3.

[0062] Calculate and obtain the first preset value according to the steady-state sine wave peak value and the amplitudes of multiple waveforms of the first echo signal, including: squaring the peak value of the first wave, the peak values of two adjacent waveforms after the first wave, and the steady-state sine wave peak value in the first echo signal respectively to obtain the energy peak value of the first wave, the energy peak values of two adjacent waveforms after the first wave (the energy peak value of the first adjacent wave, the energy peak value of the second adjacent wave, and the energy peak value of the steady-state sine wave) in the first echo signal; normalizing the energy peak value of the first wave, the energy peak values of two adjacent waveforms after the first wave (the energy peak value of the first adjacent wave and the energy peak value of the second adjacent wave) in the first echo signal respectively using the energy peak value of the steady-state sine wave in the first echo signal to obtain the first normalization value of the first wave, the first normalization value of the first adjacent wave, and the first normalization value of the second adjacent wave in the first echo signal; calculating the sum of the first normalization value of the first wave, the first normalization value of the first adjacent wave, and the first normalization value of the second adjacent wave in the first echo signal to obtain the sum of the first normalization values as the first preset value.

[0063] Obtain the second preset value of the second echo signal according to the initial threshold, including: determining the first wave, the first adjacent wave, and the second adjacent wave from the second echo signal according to the initial threshold; determining the steady-state sine wave peak value when the second echo signal reaches the steady state; squaring the peak value of the first wave, the peak value of the first adjacent wave, the peak value of the second adjacent wave, and the steady-state sine wave peak value in the second echo signal respectively to obtain the energy peak value of the first wave, the energy peak value of the first adjacent wave, the energy peak value of the second adjacent wave, and the energy peak value of the steady-state sine wave in the echo signal to be measured; normalizing the energy peak value of the first wave, the energy peak value of the first adjacent wave, and the energy peak value of the second adjacent wave in the echo signal to be measured respectively using the energy peak value of the steady-state sine wave in the echo signal to be measured to obtain the second normalization value of the first wave, the second normalization value of the first adjacent wave, and the second normalization value of the second adjacent wave in the echo signal to be measured; calculating the sum of the second normalization values of the first wave, the first adjacent wave, and the second adjacent wave in the echo signal to be measured as the second preset value.

[0064] Obtaining a second threshold according to the ratio of a second preset value to a first preset value includes: dividing the second preset value by the first preset value to obtain a normalized quantity ratio; if the normalized quantity ratio is less than a first limit value, the second threshold is equal to the initial threshold plus one; if the normalized quantity ratio is greater than a second limit value, the second threshold is equal to the initial threshold minus one; if the normalized quantity ratio is within the range of being greater than or equal to the first limit value and less than or equal to the second limit value, adjust the initial threshold according to the first wave pulse width of the first echo signal to obtain the second threshold.

[0065] The first wave is a sine wave when the amplitude of the echo signal first reaches the threshold; the first subsequent wave is the first sine wave after the first wave; the second subsequent wave is the second sine wave after the first wave.

[0066] When an ultrasonic flowmeter is installed in a pipe section, it is generally affected by interference such as fouling on the surface of the transducer, more impurities, and noise. The appearance of these interferences will cause changes in the amplitude of the transducer signal, resulting in false waves, thus affecting the measurement accuracy and stability. To address the above problems, based on the principle that the waveform energy ratios of the transducers are basically the same, in actual applications, the initial threshold and the first echo signal are both carried out during factory debugging. After installation, the second preset value of the second echo signal is obtained according to the initial threshold, and then the ratio of the second preset value to the first preset value is calculated to determine whether there are false waves in the ultrasonic flowmeter. And based on the false wave situation, the initial threshold is adjusted in real time according to the initial threshold to obtain the second threshold, and then the first wave of the third echo signal is obtained according to the second threshold to solve the problem of false waves.

[0067] After installation, by squaring the second echo waveform received by the transducer and simultaneously normalizing the waveform, the energy normalization value (normalized value) of each waveform is obtained as the second preset value. Specifically, add the energy normalization values (normalized values) of the first wave and the second wave (the first subsequent wave) and the third wave (the second subsequent wave) after the first wave in the second echo signal obtained according to the initial threshold, and compare it with the first preset value calculated and set according to the first echo signal during factory debugging. According to the ratio of the two, it can be determined whether there are false waves. If there are false waves, the initial threshold can be adjusted specifically by judging the direction of the false waves to obtain the second threshold, so that the second threshold can adapt to the waveform change in real time, thus solving the problem of false waves in principle. The preset energy normalization value (the first preset value) can be obtained through tests on several transducers. When there is no false wave situation, the second threshold can be obtained by adjusting the initial threshold through the pulse width.

[0068] Next, taking the number of continuous waveforms as 3 as an example, the embodiments of the present application will be further described as follows Figure 2 as shown

[0069] First, set the initial threshold. According to the principle that the energy ratios of the transducer echo signals are basically the same, normalize the first echo signal to obtain the peak value of each sine wave in the normalized echo signal, compare the differences between each peak value, and determine the two sine waves with the largest peak difference. Average the peak values of these two sine waves and multiply by the maximum amplitude of the unnormalized first echo signal to obtain the initial threshold. The first echo signal can be an echo signal without interference.

[0070] After determining the initial threshold, determine the first wave, the first secondary wave, and the second secondary wave of the first echo signal. When the amplitude of the first echo signal obtained by the transducer first reaches the initial threshold, the sine wave whose amplitude reaches the initial threshold is the first wave. Obtain the peak values of the first wave and the two subsequent sine waves (the first secondary wave and the second secondary wave), and at the same time obtain the peak value of the steady-state sine wave that reaches the steady state in the first echo signal obtained by the transducer. Square the peak values of these four sine waves to obtain the energy peak values of the four sine waves. As Figure 3 shown in the sine wave in the echo signal, where the ordinate is the amplitude and the abscissa is the time. The sine waves in region A1 are all steady-state sine waves. The average value of the peak values of multiple steady-state sine waves in region A1, or the steady-state sine wave with the largest peak value, or the peak value of a certain steady-state sine wave among them can be used. Normalize the energy peak values of the first wave and the two subsequent sine waves respectively, and calculate the first normalization value of the first wave and the two subsequent sine waves, and sum them as the first preset value. As shown in the following formula:

[0071]

[0072] E def = E1 + E2 + E3

[0073] In the formula, i is the number of the wave, V i is the peak value of each wave, that is, V1 is the peak value of the first wave, V2 is the peak value of the second secondary wave, V3 is the peak value of the third secondary wave, V max is the peak value of the steady-state sine wave when the amplitude of the first echo signal obtained by the transducer reaches the steady state, E i is the first normalization value of each wave, that is, E1 is the first normalization value of the first wave, E2 is the first normalization value of the second secondary wave, E3 is the first normalization value of the third secondary wave, E def is the first preset value.

[0074] In an actual application scenario, obtain the real-time echo signal as the second echo signal. According to the second echo signal, use the above method for calculating the first preset value to calculate the second preset value. Use the first wave, the first secondary wave, the second secondary wave in the second echo signal and the peak value of the steady-state sine wave when the amplitude of the second echo signal reaches the steady state, and calculate the second normalization values of the first wave, the first secondary wave, and the second secondary wave in the second echo signal respectively, and sum them to obtain the second normalization value sum and E mea, as the second preset value, and divide the second preset value by the first preset value to obtain the energy normalization quantity ratio (normalization ratio) R:

[0075]

[0076] Adjust the initial threshold E1 according to the normalization ratio R to obtain the second threshold E2.

[0077]

[0078] The above is the algorithm E2 for wrong wave situation judgment: if the normalization ratio R is less than the first limit value 0.625, it is considered that a forward wrong wave occurs in this measurement (E1 -1 ), and it is necessary to increase the initial threshold by 1 mV and compensate the time - of - flight difference; if R is greater than or equal to the first limit value 0.625 and less than or equal to the second limit value 1.725, it is considered that no wrong wave occurs in this measurement (E10), and at the same time, judge the pulse width of the first wave in the echo signal to be measured. If the pulse width is greater than 0.7, it is necessary to increase the initial threshold by 1 mV. If the pulse width is less than 0.5, it is necessary to decrease the initial threshold by 1 mV; if R is greater than the second limit value 1.725, it is considered that a backward wrong wave occurs in this measurement (E11), and it is necessary to decrease the initial threshold by 1 mV and compensate the time - of - flight difference.

[0079] In the case of wrong wave, adjusting the second threshold and compensating the time - of - flight difference in real time according to the initial threshold can avoid and solve the problem of wrong wave. Based on this, the flow value can be obtained through the flow calculation formula of the velocity difference method.

[0080] When calculating according to the new echo signal obtained based on the second threshold later, the second threshold is the second threshold after the last update. Use the updated second threshold and the new echo signal to calculate and update the second preset value.

[0081] When the calculation method of the embodiment of the present application is not used, if problems such as transducer scaling, bubbles, and noise interference occur, it will cause the amplitude to decrease. If the initial threshold cannot be adjusted in real time, continuous wrong waves will occur and cannot be restored; after using this algorithm, the system will compensate the time - of - flight difference according to the wrong wave situation and adjust the second threshold in real time according to the wrong wave situation and the pulse width, solve the wrong wave problem, and improve the measurement accuracy.

[0082] Alternative solutions of the embodiments of the present application further include: using the amplitude ratio instead of the energy ratio and obtaining the amplitude normalization value ratio can still be used for miswave judgment and compensation, which is based on the square relationship between the energy and amplitude of the ultrasonic echo signal. However, since the energy is the square of the amplitude, the fault tolerance of using the amplitude ratio will decrease. However, using the amplitude ratio instead of the energy ratio can reduce a certain amount of calculation.

[0083] In a second aspect, according to an embodiment of the present application, an ultrasonic flowmeter is provided, and this ultrasonic flowmeter uses the above anti-miswave method for ultrasonic flowmeters to determine a second threshold.

[0084] In the method of the present application, from the perspective of mechanical wave energy, by calculating a first preset value of the first echo signal and a second preset value of the second echo signal, and based on the ratio of the first preset value and the second preset value, a second threshold is calculated based on the initial threshold. The logic is simple, which is conducive to real-time calculation, can avoid the influence of miswaves, reduce the influence of interference on the measurement result, improve the measurement accuracy, and can clearly distinguish whether there is a miswave and which specific situation of the miswave. By analyzing the miswave situation, the initial threshold is adjusted in real time, so that the system can recover from the miswave state and avoid the miswave state from being maintained all the time, resulting in measurement deviation. The embodiments of the present application start from the energy perspective, use the energy normalization value as the preset value, judge whether there is a miswave by calculating the energy normalization value ratio (normalization ratio), and determine the miswave situation according to the range of the energy normalization value ratio.

[0085] The above is only a specific and preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An anti-false wave method for an ultrasonic flowmeter, characterized in that, Including: Setting an initial threshold; The setting of the initial threshold includes: obtaining a first echo signal; determining the maximum amplitude of the first echo signal; calculating the initial threshold according to the maximum amplitude and the peak average value of the two sine waves with the largest peak difference in the first echo signal; According to the initial threshold, obtain the peak value of the steady-state sine wave and the amplitudes of multiple consecutive waveforms that exceed the initial threshold and are before the steady-state sine wave from the first echo signal, where the multiple consecutive waveforms include: the first wave and the adjacent waveforms after the first wave; Calculate a first preset value according to the peak value of the steady-state sine wave of the first echo signal and the amplitudes of the multiple consecutive waveforms; Obtain a second preset value of the second echo signal according to the initial threshold; determine the first wave, the first adjacent wave, and the second adjacent wave from the second echo signal according to the initial threshold; determine the peak value of the steady-state sine wave when the second echo signal reaches the steady state; calculate a second preset value according to the peak value of the steady-state sine wave of the second echo signal and the peak values of the first wave, the first adjacent wave, and the second adjacent wave; Obtain a second threshold according to the ratio of the second preset value to the first preset value; the obtaining of the second threshold according to the ratio of the second preset value to the first preset value includes: dividing the second preset value by the first preset value to obtain a normalized ratio; if the normalized ratio is less than a first limit value, the second threshold is equal to the initial threshold plus one; if the normalized ratio is greater than a second limit value, the second threshold is equal to the initial threshold minus one; if the normalized ratio is within the range of being greater than or equal to the first limit value and less than or equal to the second limit value, adjust the initial threshold according to the pulse width of the first wave of the first echo signal to obtain the second threshold; Obtain the first wave of the third echo signal according to the second threshold; the first wave is the sine wave when the amplitude of the echo signal first reaches the threshold; the first adjacent wave is the first sine wave after the first wave; the second adjacent wave is the second sine wave after the first wave.

2. The anti-false wave method for an ultrasonic flowmeter according to claim 1, wherein, After obtaining the first wave of the third echo signal according to the second threshold, it further includes: Obtain a new echo signal and update the second preset value according to the second threshold; Update the second threshold according to the ratio of the updated second preset value to the first preset value.

3. The anti-error wave method for an ultrasonic flowmeter according to claim 1, characterized in that, The calculating the initial threshold according to the maximum amplitude and the peak average value of the two sine waves with the largest peak difference in the first echo signal includes: Normalize the obtained first echo signal; Compare the peak values of each sine wave in the normalized first echo signal to obtain the two sine waves with the largest peak difference; Calculate the peak average value of the two sine waves with the largest peak difference; Multiply the peak average value by the maximum amplitude of the first echo signal to obtain the initial threshold.

4. The anti-false wave method for an ultrasonic flowmeter according to claim 1, characterized in that, The calculating a first preset value according to the peak value of the steady-state sine wave of the first echo signal and the amplitudes of the multiple consecutive waveforms includes: Square the peak value of the first wave, the peak values of two adjacent waveforms after the first wave, and the peak value of the steady-state sine wave in the first echo signal respectively, to obtain the energy peak value of the first wave, the energy peak values of two adjacent waveforms after the first wave, and the energy peak value of the steady-state sine wave in the first echo signal; Use the energy peak value of the steady-state sine wave in the first echo signal to normalize the energy peak value of the first wave and the energy peak values of two adjacent waveforms after the first wave in the first echo signal respectively, to obtain the first normalization value of the first wave, the first normalization value of the first adjacent wave, and the first normalization value of the second adjacent wave in the first echo signal; Calculate the sum of the first normalization value of the first wave, the first normalization value of the first adjacent wave, and the first normalization value of the second adjacent wave in the first echo signal, to obtain the sum of the first normalization values as the first preset value.

5. The anti-error wave method for an ultrasonic flowmeter according to claim 1, wherein The obtaining of the second preset value of the second echo signal according to the initial threshold includes: Determine the first wave, the first adjacent wave, and the second adjacent wave from the second echo signal according to the initial threshold; Determine the peak value of the steady-state sine wave when the second echo signal reaches the steady state; Square the peak value of the first wave, the peak value of the first adjacent wave, the peak value of the second adjacent wave, and the peak value of the steady-state sine wave in the second echo signal respectively, to obtain the energy peak value of the first wave, the energy peak value of the first adjacent wave, the energy peak value of the second adjacent wave, and the energy peak value of the steady-state sine wave in the second echo signal; Use the energy peak value of the steady-state sine wave in the second echo signal to normalize the energy peak value of the first wave, the energy peak value of the first adjacent wave, and the energy peak value of the second adjacent wave in the second echo signal respectively, to obtain the second normalization value of the first wave, the second normalization value of the first adjacent wave, and the second normalization value of the second adjacent wave in the second echo signal; Calculate the sum of the second normalization values of the first wave, the first adjacent wave, and the second adjacent wave in the second echo signal as the second preset value.

6. An ultrasonic flowmeter, characterized in that, The ultrasonic flowmeter uses the anti-error wave method for ultrasonic flowmeter according to any one of claims 1-5 to determine the second threshold.

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