A gas ultrasonic flowmeter and its wave jump identification and correction method

Abstract

The present invention provides a gas ultrasonic flowmeter and a method for wave skip identification and correction thereof. The flowmeter includes a microprocessor, an amplifier, a first comparator, a timer, a sampling switching circuit, a second comparator, a logic control circuit, and a counter. The method uses a timer to calculate the time difference between the square wave signal and the excitation wave emission time to obtain the ultrasonic transmission time t0 and the average period T of the received wave. A counter is connected to the output end of the second comparator and collects the number of pulses N of the pulse signal output by the second comparator. The microprocessor identifies wave skips based on the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission time t0 to obtain the corrected ultrasonic transmission time t. The present invention can effectively identify wave skips and, after determining the preceding and following wave skips and the number of wave skips, correct the forward and reverse ultrasonic transmission times, thereby ensuring accurate measurement of the time difference value and improving the accuracy and reliability of flow measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of gas ultrasonic flowmeters, and in particular to a gas ultrasonic flowmeter and a wave jump identification and correction method thereof. Background Art

[0002] Gas ultrasonic flowmeters measure highly variable media types, pressures, and temperatures, resulting in extremely complex operating conditions. The signal received by the transducer at the receiving end of a gas ultrasonic flowmeter is only in the sub-millivolt range and is highly unstable. After amplification by the amplifier, the output signal not only struggles to maintain its amplitude within the target range but is also often contaminated by various noise signals. Currently, battery-powered gas ultrasonic flowmeters typically employ the time-of-day measurement principle, essentially employing zero-crossing detection to measure the forward and reverse durations of ultrasonic wave transmission in closed pipes. Post-amplification, unstable signal amplitude or noise interference can easily lead to false triggering of the zero-crossing detection circuit. For example, complex metering conditions, including turbulent flow, pipeline noise, and ambient electromagnetic radiation, can cause the amplitude of the amplified received wave to be highly unstable. Conventional zero-crossing detection methods are prone to wave skipping, resulting in inaccurate average period of the received wave, leading to erroneous measurements or even measurement failure. This can lead to inaccurate flow measurement or even failure of the gas ultrasonic flowmeter. Summary of the Invention

[0003] In view of the above problems, the present invention innovatively proposes an embodiment of a gas ultrasonic flowmeter and its wave jump identification and correction method to solve the technical problem that the existing gas ultrasonic flowmeter is prone to wave jumps during zero-crossing detection, which affects the measurement accuracy of the flowmeter. It can effectively identify wave jumps and correct the forward and reverse transmission time of the ultrasonic wave after determining the front and rear wave jumps and the number of wave jumps, thereby ensuring accurate measurement of the time difference value and improving the accuracy and reliability of flow measurement.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides a gas ultrasonic flow meter, characterized in that it includes a microprocessor and an amplifier, a first comparator, a timer, a sampling switching circuit, a second comparator, a logic control circuit, and a counter respectively connected to the microprocessor.

[0006] The amplifier amplifies the receiving signal of the receiving transducer and outputs a receiving amplified signal;

[0007] The non-inverting input terminal of the first comparator is electrically connected to the output terminal of the amplifier, and the first comparator performs a zero-crossing comparison on the received amplified signal and outputs a square wave signal;

[0008] The timer is electrically connected to the output end of the first comparator, and the timer calculates the time difference between the square wave signal and the time when the excitation wave is emitted to obtain the ultrasonic transmission time t0 and the average period T of the receiving wave;

[0009] The sampling switching circuit includes two peak sampling and holding circuits, one of which is connected to the output end of the amplifier, and the other is connected to the inverting input end of the second comparator. The peak sampling and holding circuits are used to collect the signal peak value in each cycle of the received amplified signal;

[0010] The logic control circuit is connected to the sampling switching circuit and the second comparator respectively, and the logic control circuit controls the two peak sampling and holding circuits of the sampling switching circuit to swap according to the square wave signal;

[0011] The counter is connected to the output end of the second comparator, and the counter collects the number N of pulses of the pulse signal output by the second comparator;

[0012] After the microprocessor is initialized, the number M of incremental waves of the received amplified signal is collected and stored in a fixed manner under the condition of no wave hopping;

[0013] The microprocessor identifies the wave hopping according to the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission time length t0 to obtain the corrected ultrasonic transmission time length t.

[0014] In a second aspect, the present invention provides a wave jump identification and correction method for a gas ultrasonic flowmeter, which is applied to a gas ultrasonic flowmeter and comprises the following steps:

[0015] Step 1, initialization;

[0016] Step 2: amplifying the received signal from the receiving transducer of the measurement channel through an amplifier to obtain a received amplified signal, and adjusting the amplifier gain so that the received amplified signal is within the required amplitude range;

[0017] Step 3: Under the condition of no wave hopping, the number M of incremental waves of the received amplified signal is collected and stored fixedly;

[0018] Step 4, using the first comparator to perform zero-crossing comparison on the received amplified signal and output a square wave signal;

[0019] Step 5: The timer calculates the time difference between the square wave signal and the excitation wave emission time to obtain the ultrasonic transmission time t0 and the average period T of the received wave;

[0020] Step 6: The logic control circuit controls the two peak sampling and holding circuits of the sampling switching circuit to swap according to the square wave signal, and outputs a pulse signal after comparison by the second comparator;

[0021] Step 7: The microprocessor reads the number of pulses of the pulse signal and counts the number of pulses as N;

[0022] In step 8, the microprocessor identifies the wave hopping according to the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission time t0 to obtain the corrected ultrasonic transmission time t.

[0023] Furthermore, in step 6, the logic control circuit controls the first sample-and-hold circuit and the second sample-and-hold circuit of the sampling switching circuit to swap according to the square wave signal, including the following steps:

[0024] Step 6.1: When the logic control circuit receives the rising edge of the first period of the square wave of the square wave signal output by the first comparator, it connects one peak sampling and holding circuit of the sampling switching circuit to the output terminal of the amplifier to collect the signal peak of the first period of the received amplified signal, and connects another peak sampling and holding circuit of the sampling switching circuit to the inverting terminal of the second comparator.

[0025] Step 6.2: When the logic control circuit receives the rising edge of the second period of the square wave of the square wave signal output by the first comparator, it switches the peak sampling and holding circuit originally connected to the output terminal of the amplifier to the inverting terminal of the second comparator, and switches the peak sampling and holding circuit originally connected to the inverting terminal of the second comparator to the output terminal of the amplifier to collect the signal peak of the second period of the received amplified signal;

[0026] Step 6.3. After that, when the logic control circuit receives the rising edge of the next cycle square wave of the square wave signal output by the first comparator each time, it switches the peak sampling and holding circuit of the switching circuit originally connected to the output end of the amplifier to the inverting end of the second comparator, and switches the peak sampling and holding circuit of the sampling switching circuit originally connected to the inverting end of the second comparator to the output end of the amplifier, and collects the signal peak value corresponding to the subsequent cycle waveform of the received amplified signal.

[0027] Furthermore, in step 6,

[0028] If the signal peak value of the next cycle waveform of the received amplified signal is higher than the signal peak value of the previous cycle waveform collected, the second comparator outputs a pulse signal;

[0029] If the signal peak value of the waveform of the received amplified signal in the next cycle is lower than the signal peak value of the received amplified signal in the previous cycle, the second comparator does not output a pulse signal.

[0030] Furthermore, in step 8, the wave hopping identification method is:

[0031] If N=M, it is determined that there is no wave hopping and the ultrasonic transmission time t0 is measured correctly;

[0032] If N>M, it is determined to jump forward, and the number of jump waves is NM;

[0033] If N<M, it is determined to jump backward, and the number of jumps is MN.

[0034] Furthermore, in step 8, the wave hopping correction method is:

[0035] If it is determined to jump forward, then set t = t0 + (NM) × T;

[0036] If it is determined to be a backward wave jump, then set t = t0-(MN)×T;

[0037] Where t represents the corrected ultrasonic transmission duration, t0 represents the ultrasonic transmission duration detected by the timer, and T is the average period of the received wave.

[0038] Furthermore, it also includes:

[0039] During each high level period of the square wave signal output by the first comparator, determining whether the second pair of comparators outputs a pulse signal;

[0040] If the second comparator has no pulse output, the control logic control circuit turns off the enable terminal of the second comparator, uses the microprocessor to put the sampling switching circuit into a discharge state, and turns off the amplifier, the first comparator and the second comparator;

[0041] When the measuring channel receiving transducer sends a receiving signal next time, the process returns to step 1.

[0042] Furthermore, in step 1, the initialization step includes:

[0043] Step 1.1, using a microprocessor to initialize the sampling switching circuit and the logic control circuit;

[0044] Step 1.2, using the microprocessor to enable the amplifier and adjust its gain;

[0045] Step 1.3, enabling the first comparator after delaying for a first time interval using a microprocessor;

[0046] In step 1.4, the counter is cleared to zero and then enabled using the microprocessor.

[0047] Furthermore, in step 2, the method for adjusting the amplitude of the received amplified signal is:

[0048] Use a microprocessor to read the signal peak value and determine whether the signal peak value is within the required amplitude range;

[0049] If the signal peak is within the required amplitude range, no adjustment is performed;

[0050] If the signal peak is not within the required amplitude range, the gain is adjusted.

[0051] Furthermore, the gain adjustment method is:

[0052] Let the required amplitude be V0, the amplifier gain be G1, and the amplitude after amplification by the amplifier be V1;

[0053] The gain is required to be adjusted to

[0054] The required amplitude range is 800-1000mV.

[0055] As can be seen from the above description, the present invention utilizes a timer to calculate the time difference between the square wave signal and the moment the excitation wave is emitted, thereby obtaining the ultrasonic transmission duration and the average period of the received wave; utilizes a counter to collect the number of pulses N of the pulse signal output by the second comparator; utilizes a microprocessor to identify wave jumps based on the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission duration to obtain the corrected ultrasonic transmission duration. This method effectively identifies wave jumps and, after determining the preceding and following wave jumps and the number of wave jumps, corrects the ultrasonic forward and reverse transmission times, thereby ensuring accurate measurement of the time difference and improving the accuracy and reliability of flow measurement. This method enhances the adaptability of battery-powered gas ultrasonic flowmeters to media and environments, significantly improves measurement accuracy and reliability, further broadens the application of gas ultrasonic flowmeters, and effectively reduces measurement disputes. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 FIG2 is a schematic structural diagram of a gas ultrasonic flowmeter provided by one embodiment of the present invention;

[0057] Figure 2 FIG2 is a flow chart of a method for identifying and correcting a wave jump of a gas ultrasonic flowmeter according to an embodiment of the present invention;

[0058] Figure 3 It is a schematic diagram showing the relationship among the received amplified signal, the square wave signal output by the first comparator and the pulse signal output by the second comparator according to the present invention. DETAILED DESCRIPTION

[0059] To make the objectives, technical solutions, and advantages of the present invention more clear and understandable, the present invention is further described below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0060] Based on the shortcomings of the prior art, the present invention provides a specific implementation of a gas ultrasonic flow meter, such as Figure 1 As shown, the gas ultrasonic flow meter specifically includes a microprocessor 1 and an amplifier 2, a first comparator 6, a timer 8, a sampling switching circuit 9, a second comparator 10, a logic control circuit 12 and a counter 13 respectively connected to the microprocessor 1.

[0061] The amplifier 2 amplifies the receiving signal 4 of the receiving transducer 3 and outputs the receiving amplified signal 5, so that the peak sampling and holding circuit of the sampling switching circuit 9 can collect the peak value of the waveform of the receiving amplified signal in each cycle;

[0062] The non-inverting input terminal of the first comparator 6 is electrically connected to the output terminal of the amplifier 2. The first comparator 6 performs a zero-crossing comparison on the received amplified signal 5 and outputs a square wave signal 7.

[0063] The timer 8 is electrically connected to the output end of the first comparator 6. The timer 8 calculates the ultrasonic transmission time t0 and the average period T of the received wave according to the square wave signal. The timer 8 then uses the square wave signal to obtain the forward and reverse durations. The flow rate is calculated using the time difference method based on the forward and reverse durations, thereby realizing the metering function of the gas ultrasonic flowmeter.

[0064] The sampling switching circuit 9 includes two peak sampling and holding circuits. One peak sampling and holding circuit of the sampling switching circuit 9 is connected to the output end of the amplifier 2. The peak sampling and holding circuit connected to the output end of the amplifier 2 is used to collect the signal peak value of the received amplified signal 5 output by the amplifier 2 within each cycle; the other peak sampling and holding circuit of the sampling switching circuit 9 is connected to the inverting input end of the second comparator 10. The second comparator 10 is used to compare the signal peak value of the received amplified signal 5 within each cycle;

[0065] The logic control circuit 12 is connected to the sampling switching circuit 9 and the second comparator 10 respectively. The logic control circuit 12 controls the two peak sampling and holding circuits of the sampling switching circuit 9 to swap according to the square wave signal 7, and then repeatedly uses the second comparator 10 to compare the signal peak value of the next cycle of the received amplified signal 5 with the signal peak value of the previous cycle of the received amplified signal 5;

[0066] The counter 13 is connected to the output terminal of the second comparator 10, and the counter 13 collects the number N of pulses of the pulse signal 11 output by the second comparator 10;

[0067] After initialization, the microprocessor 1 collects the number M of incremental waves of the received amplified signal 5 under the condition of no wave hopping and stores it fixedly;

[0068] The microprocessor 1 collects the number M of incremental waves of the received amplified signal 5 and reads the number N of pulses collected by the counter 13. The microprocessor identifies wave jumps based on the number M of incremental waves and the number N of pulses, and corrects the ultrasonic transmission time t0 to obtain the corrected ultrasonic transmission time t. Generally, the number of front and back wave jumps is no more than 3, so M-3≤N≤M+3. If N=M, it is determined that there are no wave jumps and the ultrasonic transmission time t0 is measured correctly.

[0069] If N>M, it is determined to jump forward, and the number of jumps is NM, then let t=t0+(NM)×T;

[0070] If N < M, it is determined to be a backward wave jump, and the number of wave jumps is MN, then let t = t0-(MN) × T;

[0071] Where t represents the corrected ultrasonic transmission duration, t0 represents the ultrasonic transmission duration detected by the timer, and T is the average period of the received wave.

[0072] In this embodiment, timer 8 calculates the ultrasonic transmission duration t0 and the average period T of the received wave based on the square wave signal; counter 13 collects the number of pulses N of the pulse signal 11 output by the second comparator 10; and microprocessor 1 collects the number of incremental waves M of the received amplified signal 5 and reads the number of pulses N collected by counter 13. The microprocessor identifies wave jumps based on the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission duration t0 to obtain the corrected ultrasonic transmission duration t. This effectively identifies wave jumps and, after determining the preceding and following wave jumps and the number of wave jumps, corrects the forward and reverse ultrasonic transmission times, thereby ensuring accurate measurement of the time difference and improving the accuracy and reliability of flow measurement. This enhances the adaptability of battery-powered gas ultrasonic flowmeters to media and environments, significantly improving measurement accuracy and reliability, further expanding the application of gas ultrasonic flowmeters and effectively reducing metering disputes.

[0073] The present invention also provides a wave jump identification and correction method for a gas ultrasonic flowmeter, which is applied to the above-mentioned gas ultrasonic flowmeter, such as Figure 2 and combined Figure 3 As shown, the method specifically includes the following steps:

[0074] Step 1, initialization;

[0075] Specifically, in step 1, initialization includes the following steps:

[0076] Step 1.1, using a microprocessor to initialize the sampling switching circuit and the logic control circuit;

[0077] Step 1.2, using the microprocessor to enable the amplifier and adjust its gain;

[0078] Step 1.3, using the microprocessor to delay for a first time interval and then enable the first comparator; the first time interval is generally slightly shorter than the forward duration at the maximum gas flow rate to ensure a more accurate zero-crossing comparison after the first comparator is enabled;

[0079] In step 1.4, the counter is cleared to zero and then enabled using the microprocessor.

[0080] An initialization step is required before each test to ensure that each component is in a state to be tested and is not disturbed by the original settings, thereby improving the accuracy of the test.

[0081] Step 2: amplifying the received signal from the receiving transducer of the measurement channel through an amplifier to obtain a received amplified signal, and adjusting the amplifier gain so that the received amplified signal is within the required amplitude range;

[0082] Specifically, in step 2, the method for adjusting the amplitude of the received amplified signal is:

[0083] Use a microprocessor to read the signal peak value and determine whether the signal peak value is within the required amplitude range;

[0084] If the signal peak is within the required amplitude range, no adjustment is performed;

[0085] If the signal peak value is not within the required amplitude range, the gain is adjusted;

[0086] If the peak value of the received amplified signal does not reach the required amplitude range, make the following adjustments:

[0087] Let the required amplitude be V0, the amplifier gain be G1, and the amplitude after amplification by the amplifier be V1;

[0088] The gain is required to be adjusted to The required amplitude range is 800-1000mV.

[0089] By setting a reasonable amplitude range, the response speed of the second comparator is effectively guaranteed, and reasonable control under various error conditions is met.

[0090] Step 3: Under the condition of no wave hopping, the number M of incremental waves of the received amplified signal is collected and stored fixedly;

[0091] Increasing wave: If the signal peak of the next cycle waveform is greater than the signal peak of the previous cycle waveform, the next cycle waveform is considered to be an increasing wave;

[0092] Step 4, using the first comparator to perform zero-crossing comparison on the received amplified signal and output a square wave signal;

[0093] Step 5: The timer calculates the time difference between the square wave signal and the excitation wave emission time to obtain the ultrasonic transmission time t0 and the average period T of the received wave;

[0094] Specifically, a timer is used to obtain the forward duration and the reverse duration according to the square wave signal; the flow rate is calculated using the time difference method according to the forward duration and the reverse duration, thereby realizing the metering function of the gas ultrasonic flow meter;

[0095] Step 6: The logic control circuit controls the two peak sampling and holding circuits of the sampling switching circuit to swap according to the square wave signal, and outputs a pulse signal after comparison by the second comparator;

[0096] In step 6, specifically, the following steps are included:

[0097] Step 6.1: When the logic control circuit receives the rising edge of the first period of the square wave of the square wave signal output by the first comparator, it connects one peak sampling and holding circuit of the sampling switching circuit to the output terminal of the amplifier to collect the signal peak value Vp1 of the first period of the received amplified signal, and connects another peak sampling and holding circuit of the sampling switching circuit to the inverting terminal of the second comparator. At this time, the second comparator is not enabled and does not output a pulse signal.

[0098] Step 6.2: When the logic control circuit receives the rising edge of the second period of the square wave of the square wave signal output by the first comparator, it switches the peak sampling and holding circuit originally connected to the output terminal of the amplifier to the inverting terminal of the second comparator, and switches the peak sampling and holding circuit originally connected to the inverting terminal of the second comparator to the output terminal of the amplifier, so as to collect the signal peak value Vp2 of the second period of the received amplified signal. At this time, the second comparator is enabled, and the two input ports of the second comparator respectively input the signal peak value Vp1 of the first period of the waveform and the signal peak value Vp2 of the second period of the waveform, so that the second comparator compares Vp1 with Vp2.

[0099] Step 6.3. After that, when the logic control circuit receives the rising edge of the next cycle square wave of the square wave signal output by the first comparator each time, it switches the peak sampling and holding circuit of the switching circuit originally connected to the output end of the amplifier to the inverting end of the second comparator, and switches the peak sampling and holding circuit of the sampling switching circuit originally connected to the inverting end of the second comparator to the output end of the amplifier, and collects the signal peak value corresponding to the subsequent cycle waveform of the received amplified signal for comparison with the signal peak value of the next cycle waveform.

[0100] by Figure 3 For example, the comparison process of the second comparator is shown in the following table:

[0101]

[0102] More specifically, in step 6, the pulse signal output by the second comparator is generated according to the following rules:

[0103] If the signal peak value of the next cycle waveform of the received amplified signal is higher than the signal peak value of the previous cycle waveform collected, the second comparator outputs a pulse signal;

[0104] If the signal peak value of the waveform of the received amplified signal in the next cycle is lower than the signal peak value of the received amplified signal in the previous cycle, the second comparator does not output a pulse signal.

[0105] Step 7: The microprocessor reads the number of pulses of the pulse signal and counts the number of pulses as N;

[0106] like Figure 3 As shown, it can be seen that the number of increasing waves should correspond to the number of pulses output by the second comparator;

[0107] In step 8, the microprocessor identifies the wave hopping according to the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission time t0 to obtain the corrected ultrasonic transmission time t.

[0108] Specifically, in step 8, the wave hopping identification method is:

[0109] If N=M, it is determined that there is no wave hopping and the ultrasonic transmission time t0 is measured correctly;

[0110] If N>M, it is determined to jump forward, and the number of jump waves is NM;

[0111] If N < M, it is determined to be a backward wave jump, and the number of wave jumps is MN;

[0112] If a wave jump is detected, perform correction as follows:

[0113] If it is determined to jump forward, then set t = t0 + (NM) × T;

[0114] If it is determined to be a backward wave jump, then set t = t0-(MN)×T;

[0115] Where t represents the corrected ultrasonic transmission duration, t0 represents the ultrasonic transmission duration detected by the timer, and T is the average period of the received wave.

[0116] On the basis of the above steps, the step of ending the detection is also included, that is, step 9:

[0117] During each high level period of the square wave signal output by the first comparator, determining whether the second pair of comparators outputs a pulse signal;

[0118] If the second comparator has no pulse output, the control logic control circuit turns off the enable terminal of the second comparator, uses the microprocessor to put the sampling switching circuit into a discharge state, and turns off the amplifier, the first comparator and the second comparator;

[0119] When the measuring channel receiving transducer sends a receiving signal next time, the process returns to step 1 to wait for the start of the next detection.

[0120] This embodiment effectively identifies wave jumps and, after determining the preceding and following wave jumps and their number, corrects the forward and reverse transmission times of the ultrasonic wave. This ensures accurate measurement of the time difference, improving the accuracy and reliability of flow measurement. This enhances the adaptability of battery-powered ultrasonic gas flowmeters to media and environments, significantly improving measurement accuracy and reliability. This can further expand the application of ultrasonic gas flowmeters while effectively reducing measurement disputes.

[0121] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A gas ultrasonic flow meter, characterized in that: The device comprises a microprocessor and an amplifier, a first comparator, a timer, a sampling switching circuit, a second comparator, a logic control circuit and a counter respectively connected to the microprocessor. The amplifier amplifies the receiving signal of the receiving transducer and outputs a receiving amplified signal; The non-inverting input terminal of the first comparator is electrically connected to the output terminal of the amplifier, and the first comparator performs a zero-crossing comparison on the received amplified signal and outputs a square wave signal; The timer is electrically connected to the output end of the first comparator, and the timer calculates the time difference between the square wave signal and the time when the excitation wave is emitted to obtain the ultrasonic transmission time t0 and the average period T of the receiving wave; The sampling switching circuit includes two peak sampling and holding circuits, one of which is connected to the output end of the amplifier, and the other is connected to the inverting input end of the second comparator. The peak sampling and holding circuits are used to collect the signal peak value in each cycle of the received amplified signal; The logic control circuit is connected to the sampling switching circuit and the second comparator respectively, and the logic control circuit controls the two peak sampling and holding circuits of the sampling switching circuit to swap according to the square wave signal; The counter is connected to the output end of the second comparator, and the counter collects the number N of pulses of the pulse signal output by the second comparator; After the microprocessor is initialized, the number M of incremental waves of the received amplified signal is collected and stored in a fixed manner under the condition of no wave hopping; The microprocessor identifies the wave hopping according to the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission time length t0 to obtain the corrected ultrasonic transmission time length t.

2. A method for wave jump identification and correction of a gas ultrasonic flowmeter, applied to the gas ultrasonic flowmeter according to claim 1, characterized in that: The steps include: Step 1, initialization; Step 2: amplifying the received signal from the receiving transducer of the measurement channel through an amplifier to obtain a received amplified signal, and adjusting the amplifier gain so that the received amplified signal is within the required amplitude range; Step 3: Under the condition of no wave hopping, the number M of incremental waves of the received amplified signal is collected and stored fixedly; Step 4, using the first comparator to perform zero-crossing comparison on the received amplified signal and output a square wave signal; Step 5: The timer calculates the time difference between the square wave signal and the excitation wave emission time to obtain the ultrasonic transmission time t0 and the average period T of the received wave; Step 6: The logic control circuit controls the two peak sampling and holding circuits of the sampling switching circuit to swap according to the square wave signal, and outputs a pulse signal after comparison by the second comparator; Step 7: The microprocessor reads the number of pulses of the pulse signal and counts the number of pulses as N; In step 8, the microprocessor identifies the wave hopping according to the number of incremental waves M and the number of pulses N, and corrects the ultrasonic transmission time t0 to obtain the corrected ultrasonic transmission time t.

3. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 2, wherein: In step 6, the logic control circuit controls the first sample-and-hold circuit and the second sample-and-hold circuit of the sampling switching circuit to swap according to the square wave signal, including the following steps: Step 6.1: When the logic control circuit receives the rising edge of the first period of the square wave of the square wave signal output by the first comparator, it connects one peak sampling and holding circuit of the sampling switching circuit to the output terminal of the amplifier to collect the signal peak of the first period of the received amplified signal, and connects another peak sampling and holding circuit of the sampling switching circuit to the inverting terminal of the second comparator. Step 6.2: When the logic control circuit receives the rising edge of the second period of the square wave of the square wave signal output by the first comparator, it switches the peak sampling and holding circuit originally connected to the output terminal of the amplifier to the inverting terminal of the second comparator, and switches the peak sampling and holding circuit originally connected to the inverting terminal of the second comparator to the output terminal of the amplifier to collect the signal peak of the second period of the received amplified signal; Step 6.

3. After that, when the logic control circuit receives the rising edge of the next cycle square wave of the square wave signal output by the first comparator each time, it switches the peak sampling and holding circuit of the switching circuit originally connected to the output end of the amplifier to the inverting end of the second comparator, and switches the peak sampling and holding circuit of the sampling switching circuit originally connected to the inverting end of the second comparator to the output end of the amplifier, and collects the signal peak value corresponding to the subsequent cycle waveform of the received amplified signal.

4. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 2, wherein: In step 6, If the signal peak value of the next cycle waveform of the received amplified signal is higher than the signal peak value of the previous cycle waveform collected, the second comparator outputs a pulse signal; If the signal peak value of the waveform of the received amplified signal in the next cycle is lower than the signal peak value of the received amplified signal in the previous cycle, the second comparator does not output a pulse signal.

5. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 2, wherein: In step 8, the wave hopping identification method is: If N=M, it is determined that there is no wave hopping and the ultrasonic transmission time t0 is measured correctly; If N>M, it is determined to jump forward, and the number of jump waves is NM; If N<M, it is determined to jump backward, and the number of jumps is MN.

6. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 5, wherein: In step 8, the wave hopping correction method is: If it is determined to jump forward, then set t = t0 + (NM) × T; If it is determined to be a backward wave jump, then set t = t0-(MN)×T; Where t represents the corrected ultrasonic transmission duration, t0 represents the ultrasonic transmission duration detected by the timer, and T is the average period of the received wave.

7. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 2, wherein: Also includes: During each high level period of the square wave signal output by the first comparator, determining whether the second pair of comparators outputs a pulse signal; If the second comparator has no pulse output, the control logic control circuit turns off the enable terminal of the second comparator, uses the microprocessor to put the sampling switching circuit into a discharge state, and turns off the amplifier, the first comparator and the second comparator; When the measuring channel receiving transducer sends a receiving signal next time, the process returns to step 1.

8. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 2, wherein: In step 1, the initialization step includes: Step 1.1, using a microprocessor to initialize the sampling switching circuit and the logic control circuit; Step 1.2, using the microprocessor to enable the amplifier and adjust its gain; Step 1.3, enabling the first comparator after delaying the first time interval by the microprocessor; In step 1.4, the counter is cleared to zero and then enabled using the microprocessor.

9. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 2, wherein: In step 2, the amplitude of the received amplified signal is adjusted as follows: Use a microprocessor to read the signal peak value and determine whether the signal peak value is within the required amplitude range; If the signal peak is within the required amplitude range, no adjustment is performed; If the signal peak is not within the required amplitude range, the gain is adjusted.

10. The method for wave jump identification and correction of a gas ultrasonic flowmeter according to claim 9, wherein: The gain adjustment method is: Let the required amplitude be V0, the amplifier gain be G1, and the amplitude after amplification by the amplifier be V1; The gain is required to be adjusted to The required amplitude range is 800-1000mV.

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