CN111121894B - Flow calibration method for ultrasonic gas meter - Google Patents
Flow calibration method for ultrasonic gas meter Download PDFInfo
- Publication number
- CN111121894B CN111121894B CN201911358973.1A CN201911358973A CN111121894B CN 111121894 B CN111121894 B CN 111121894B CN 201911358973 A CN201911358973 A CN 201911358973A CN 111121894 B CN111121894 B CN 111121894B
- Authority
- CN
- China
- Prior art keywords
- pin
- signal
- capacitor
- resistor
- comparator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
- G01F25/10—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters
- G01F25/15—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters specially adapted for gas meters
Abstract
The embodiment of the application provides a flow calibration method for an ultrasonic gas meter, which comprises the steps of receiving driving pulses output by a micro control unit, controlling a first ultrasonic transducer to emit ultrasonic signals based on the driving pulses, and generating echo signals by receiving the ultrasonic signals by a second ultrasonic transducer corresponding to the first ultrasonic transducer; performing signal amplification processing on the echo signal output by the second ultrasonic sensor to obtain an amplified echo signal; transmitting the amplified echo signal to a comparator circuit to obtain a compared signal output by the comparator circuit; the STOP signal is obtained based on the compared signals. The accuracy of generating the STOP signal head wave is ensured by adjusting the real-time amplification factor of the echo signal in real time so as to finish the measurement of the ultrasonic wave flight time according to the STOP signal.
Description
Technical Field
The application belongs to the field of signal processing, and particularly relates to a flow calibration method for an ultrasonic gas meter.
Background
With the improvement of technology development capability, ultrasonic flow meters are becoming more and more accepted in the market. In the natural gas metering industry, ultrasonic flow meters are gradually replacing ancient model gas meters. The gas ultrasonic flowmeter calculates the flow velocity of the fluid by measuring the forward flow propagation time and the backward flow propagation time of ultrasonic waves in the fluid, and then calculates the flow rate of the flowing fluid by the flow velocity. The accuracy of the transit time measurement of ultrasonic waves in a fluid is a major factor affecting the accuracy of the ultrasonic meter measurement.
The ultrasonic wave propagates in the ideal environment and medium without attenuation, namely the received signal will not change under the condition of unchanged drive, but in actual use, the components of the medium may be different, the environments such as temperature and pressure may be different, and the received signal will still change under the condition of unchanged drive. The signal generated by the ultrasonic sensor is a positive-brown wave signal taking a zero point as a reference, in the prior art, a fixed threshold value comparator is used for judging the first wave, so that the forward and backward propagation time is measured, when a medium changes, a receiving signal changes, the threshold value of the threshold value comparator is fixed, the first wave of the ultrasonic signal can be judged to be wrong, and when the first wave of one period is judged to be wrong by a 200kHz sensor for example, a time measurement error of 5us is caused, the first wave is converted into a flow velocity, and the flow velocity is converted into a very large error, so that the metering accuracy of the ultrasonic flowmeter is influenced.
Most of the ultrasonic flow meters in the market at present adopt a TDC timing chip of GP2 series to detect the flight time, echo signals judge the head wave through a fixed threshold comparator, so as to calculate the flow, when external conditions such as media are changed, the method is generally adopted to set the threshold values of a plurality of comparators, and then pre-judge and readjust the amplification factor according to the flight time tested by different threshold values, but the precision is lower, and the position of the wrong head wave is judged with great possibility, so that the flight time test is wrong, namely the ultrasonic flow meter has no flow running number in common problems.
Disclosure of Invention
In order to solve the defects and shortcomings in the prior art, the application provides a flow calibration method for an ultrasonic gas meter, and the calculation accuracy of ultrasonic flight time can be improved by adaptively amplifying echo signals, so that the effectiveness of flow calculation is ensured.
Specifically, the flow calibration method for the ultrasonic gas meter provided by the embodiment of the application comprises the following steps:
receiving driving pulses output by a micro control unit, controlling a first ultrasonic transducer to emit ultrasonic signals based on the driving pulses, and generating echo signals by receiving the ultrasonic signals by a second ultrasonic transducer corresponding to the first ultrasonic transducer;
performing signal amplification processing on the echo signal output by the second ultrasonic sensor to obtain an amplified echo signal;
transmitting the amplified echo signal to a comparator circuit to obtain a compared signal output by the comparator circuit;
the STOP signal is obtained based on the compared signals.
Optionally, the method further comprises:
the STOP signal is analyzed and compared with the echo signal such that the characteristic wave of the STOP signal coincides with the characteristic wave of the echo signal.
Optionally, the signal amplifying processing is performed on the echo signal output by the second ultrasonic sensor to obtain an amplified echo signal, including:
the echo signal is subjected to primary amplification treatment through a primary amplifier circuit;
and outputting the amplified signals to a PGA automatic gain circuit and a saturation amplifying circuit respectively for secondary amplification treatment to obtain amplified echo signals after secondary amplification.
Optionally, the outputting the amplified signals to the PGA automatic gain circuit and the saturation amplifying circuit for performing a second-stage amplification process to obtain second-stage amplified echo signals, which includes:
performing secondary amplification processing on the amplified echo signal after primary amplification in a PGA automatic gain circuit to obtain an amplified echo signal; and
and amplifying the first-stage amplified echo signal in a saturation amplifying circuit to obtain an amplified echo signal.
Optionally, the PGA automatic gain circuit includes:
the operational amplifier IC14A, the reverse input end of the operational amplifier IC14A is used for receiving the amplified result outputted by the primary amplifier circuit, the forward input end of the operational amplifier IC14A is connected with analog ground, the first control end of the operational amplifier IC14A is connected with the power supply end 2V5, meanwhile, the second control end of the operational amplifier IC14A is connected with the power supply end-2V 5 through the capacitor C30 and is connected with the signal ground through the capacitor C36, a capacitor C39 and a resistor R33 which are connected in parallel are also arranged between the output end and the reverse input end of the comparator IC14A, the output end of the comparator IC14A is connected with the INMR pin of the programmable gain amplifier IC10 through the capacitor C390, and the INMR pin is simultaneously connected with the signal ground through the resistor R21;
pin inp of programmable gain amplifier IC10 is connected to signal ground through capacitor C22 and resistor R11 in turn, pin OFSN of programmable gain amplifier IC10 is connected to signal ground through capacitor C18, resistor R12 and resistor R13 in turn, resistor R12 is arranged between pin OFSN and pin VAGC, pin VBAT of programmable gain amplifier IC10 is connected to power supply terminal 3V0, simultaneously connected to signal ground through capacitor C170 and capacitor C17 in parallel, pin OFSN and pin VREF are connected to signal ground through capacitor C16 at the same time, pin EPAD is connected to digital ground, pins DETO and COMM of programmable gain amplifier IC10 are connected to signal ground,
pin OUTP of programmable gain amplifier IC10 is connected with pin 2 of operational amplifier IC12, a capacitor C26 is connected between pin OUTP and pin FBKP of programmable gain amplifier IC10, pin OUTM of programmable gain amplifier IC10 is connected with pin 3 of operational amplifier IC12, a capacitor C29 is connected between pin OUTM and pin FBKM of programmable gain amplifier IC10, pin 1 of operational amplifier IC12 is connected with signal ground, pin 7 of operational amplifier IC12 is connected with power supply end 2V5, and at the same time is connected with signal ground via capacitor C23, and pins 5 and 6 of operational amplifier IC12 are also connected with capacitor C28;
pin GAIN of programmable GAIN amplifier IC10 is connected to pin 1 of digital-to-analog converter IC13, pin 1 of IC13 is also connected to signal ground via resistor R28, pin 2 of IC13 is connected to signal ground, pin 3 of IC13 is connected to supply terminal 3V0, and simultaneously is also connected to signal ground via capacitor C33, pin 6 of IC13 is connected to signal ground, and pins 4, 5 of IC13 are connected to supply terminal 3V0 via resistors R31, R32, respectively.
Optionally, the transmitting the amplified echo signal to the comparator circuit, to obtain a compared signal output by the comparator circuit, includes:
judging whether the waveform peak value of the amplified echo signal is in a preset interval in a comparator circuit;
if the intermediate value of the two wave peaks is calculated in the preset interval, setting the intermediate value as a compared threshold voltage through a DAC;
and if the peak value difference is outside the preset interval, performing DAC adjustment, and processing the peak value difference by means of an ADC sampling processing mode.
Optionally, the comparator circuit includes:
the reverse input end of the amplifier U11 is connected with signal ground through a resistor R204 and a resistor R22, one end of the resistor R22 far away from the signal ground is also connected with the output end TP58 of the PGA automatic gain circuit, the positive input end of the amplifier U11 is connected with the signal ground through a capacitor C201, two ends of the capacitor C201 are connected with a resistor R206 in parallel, and one end of the resistor R206 far away from the signal ground is also connected with a power supply end 3V0 through a resistor R205; the first control end of the amplifier U11 is connected with the power supply end 3V0, the first control end of the amplifier U11 is connected with signal ground through a capacitor C202 on one hand, and is connected with an offset pin on the other hand, the output end of the amplifier U11 is also connected with an AINP pin of the analog-to-digital converter U12 through a resistor R207, and the output end of the amplifier U11 is also connected with the reverse input end of the amplifier U11 through a resistor R203;
the AINP pin of the analog-digital converter U12 is also connected with signal ground through a capacitor C203, the AINM pin of the analog-digital converter U12 is grounded through a resistor R208, the SDO pin of the analog-digital converter U12 is connected with signal ground through a resistor R210 and a capacitor C205, the SCLK pin of the analog-digital converter U12 is connected with signal ground through a resistor R209 and a capacitor C205, the DVDD pin of the analog-digital converter U12 is connected with a power supply end 3V0 through a resistor R222, the AVDD pin of the analog-digital converter U12 is connected with a power supply end 3V0 through a resistor R223, and a capacitor C204 is connected between the AVDD pin and the GND pin of the analog-digital converter U12 in parallel; the AINP pin of the analog-to-digital converter U12 is also connected with the positive input end of the comparator IC7A through a capacitor C211;
the first control end of the comparator IC7A is connected with the power supply end 2V5 on one hand, and is also connected with signal ground through a capacitor C90 on the other hand, the second control end of the comparator IC7A is connected with the signal ground through a capacitor C9 on the other hand, and is connected with the power supply end-2V 5, and the output end of the comparator IC7A is sequentially connected with the signal ground through resistors R16 and R8; the reverse input end of the comparator IC7A is connected with the pin 1 of the digital-to-analog converter U10 through a resistor R211, the pin 2 and the pin 6 of the digital-to-analog converter U10 are connected with signal ground, the pin 3 of the digital-to-analog converter U10 is connected with the signal ground through a capacitor C206, two ends of the capacitor C206 are connected with a capacitor C226 in parallel, and the other end of the capacitor C206 far away from the grounding end is connected with a power supply end 3V0.
Optionally, the comparator circuit comprises
The reverse input end of the comparator IC5A is connected with the output end TP51 of the primary amplifier circuit through a resistor R14 and a capacitor C24, and the forward input end of the comparator IC5A is connected with one end of the capacitor C24 far away from TP51 through a resistor R15 on one hand and connected with signal ground on the other hand; a first control end of the comparator IC5A is connected with the power supply end 2V5, and a second control end of the comparator IC5A is connected with the power supply end-2V 5 and is grounded with signals through a capacitor C19; the output end of the comparator IC5A is electrically connected with the positive input end of the comparator IC7B through a capacitor C8;
the positive input end of the comparator IC7B is grounded through a resistor R3, the output end of the comparator IC7B is connected with the emitter of the triode Q1, the base electrode of the triode Q1 is grounded through a resistor R9, and a resistor R10 is connected in parallel between the base electrode and the emitter of the triode Q1; the collector of the triode Q1 is connected with a signal end TP61, and a resistor R6 and a capacitor C12 which are connected in parallel are arranged between the signal end TP61 and the signal ground.
Optionally, the step of obtaining the STOP signal for determining the echo signal time based on the compared signals includes:
the STOP signal circuit masks interference due to noise based on the output result, and an adjusted STOP signal is obtained.
Optionally, the STOP signal circuit includes:
a monostable resonator IC9, in which a STOP2 signal generated by the threshold comparator circuit is received at a pin 2 of the monostable resonator IC9, a pin 7 of the monostable resonator IC9 is connected to a power supply terminal 2V5 via a resistor R17, a pin 6 of the monostable resonator IC9 is connected to signal ground on the one hand, and is connected to the pin 7 via a capacitor C20 on the other hand, and a pin 8 of the monostable resonator IC9 is connected to the power supply terminal 2V5 on the one hand, and is connected to signal ground via a capacitor C371 on the other hand;
the pin 5 of the monostable resonator IC9 is provided with an output TP59, the output TP59 is connected to a first input of the and-gate chip IC1, a second input of the and-gate chip IC1 is configured to receive the STOP1 signal generated by the zero-crossing comparator, the first control of the and-gate chip IC1 is connected to the power supply terminal 2V5 on the one hand, and to the ground via the capacitor C373, the second control of the and-gate chip IC1 is connected to the ground, and the output of the and-gate chip IC1 is connected to the output TP62 for outputting the adjusted STOP signal.
The technical scheme provided by the application has the beneficial effects that:
1. by amplifying the echo signals, the accuracy of determining the moment of receiving the head wave can be improved based on the echo signals with the amplified amplitude, so that the accuracy of ultrasonic flight time is improved, and finally the accuracy of gas flow calculation is improved.
2. And analyzing the STOP signal and comparing the STOP signal with the echo signal so that the head wave of the STOP signal is consistent with the head wave of the echo signal, and keeping the waveforms in the STOP signal and the echo signal in one-to-one correspondence.
3. And (3) comparing the waveform peak value with a preset interval in the PGA automatic gain loop, and pertinently adjusting the threshold voltage of the comparator based on the comparison result, so that the threshold level is ensured to have enough margin to avoid false waves, and the calculation accuracy of the final flow is ensured.
4. An AND gate chip is additionally arranged in the STOP signal circuit, the STOP1 signal generated by the zero-crossing comparator and the output of the resonator are subjected to AND operation, and the STOP signal generated by noise can be well shielded when the monostable waveform generated by the STOP2 is subjected to AND operation with the STOP1, so that a correct STOP signal is obtained.
Drawings
In order to more clearly illustrate the technical solutions of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a flow calibration method for an ultrasonic gas meter according to an embodiment of the present application;
fig. 2 is a schematic diagram of a charge amplifier circuit according to an embodiment of the present application;
fig. 3 is a schematic diagram of a PGA automatic gain circuit according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a threshold comparator circuit according to an embodiment of the present application;
FIG. 5 is a schematic diagram showing the structure of a STOP signal generation circuit according to an embodiment of the present application;
fig. 6 is a schematic diagram of a signal amplification process according to an embodiment of the present application.
Detailed Description
In order to make the structure and advantages of the present application more apparent, the structure of the present application will be further described with reference to the accompanying drawings.
Example 1
In order to solve the defects existing in the prior art, the embodiment of the application provides a flow calibration method for an ultrasonic gas meter, as shown in fig. 1, the flow calibration method comprises the following steps:
11. receiving driving pulses output by a micro control unit, controlling a first ultrasonic transducer to emit ultrasonic signals based on the driving pulses, and generating echo signals by receiving the ultrasonic signals by a second ultrasonic transducer corresponding to the first ultrasonic transducer;
12. performing signal amplification processing on the echo signal output by the second ultrasonic sensor to obtain an amplified echo signal;
13. transmitting the amplified echo signal to a comparator circuit to obtain a compared signal output by the comparator circuit;
14. the STOP signal is obtained based on the compared signals.
In order to realize gas flow measurement based on ultrasonic waves, it is necessary to perform measurement based on ultrasonic signals generated by an ultrasonic sensor, wherein the ultrasonic signals are sine wave signals based on zero points, and in the prior art, a fixed threshold comparator is used to determine the head wave at the time of receiving an echo, so as to measure the calculation of the forward and backward propagation time. According to the flow calibration method provided by the embodiment of the application, the accuracy of generating the head wave of the STOP signal is ensured by adjusting the real-time amplification factor of the echo signal in real time, so that the measurement of the ultrasonic flight time is finished according to the STOP signal.
In steps 11, 12, a first ultrasonic transducer and a second ultrasonic transducer are mentioned, and in actual use, the first ultrasonic transducer and the second ultrasonic transducer can perform the mutual conversion of ultrasonic signal transmission and reception according to the setting.
The main technical means of the flow calibration method provided by the embodiment of the application is to execute the signal amplification processing process in the step 13. The amplification in step 13 is mainly performed by an amplifier circuit. In order to improve the signal precision in the amplifying process, the amplified signal is required to be processed in a targeted manner, and the method mainly comprises two types of threshold comparison and zero-crossing detection comparison, and is specifically processed by a threshold comparator circuit and a zero-crossing detection comparator circuit respectively.
When the flow calibration is actually performed, signal comparison operation can be further added, and analysis and comparison are performed on the STOP signal and the echo signal, so that the head wave of the STOP signal is consistent with the head wave of the echo signal. When the first waves are consistent, the adjustment and alignment of the echo signals can be completed due to the consistent sending and receiving periods of the ultrasonic signals, and further the subsequent calibration is completed.
The specific signal amplification process in step 12 is to amplify the echo signal by a first-stage amplifier circuit, and output the amplified signal to a PGA automatic gain circuit and a saturation amplifying circuit respectively for second-stage amplification. The primary amplifying circuit here is typically a charge amplifier circuit.
In an implementation, as shown in fig. 2, the charge amplifier circuit includes:
the positive input end of the operational amplifier IC14A is connected with analog ground, the negative input end of the operational amplifier IC14A is connected with an echo signal RECEIVE, and a capacitor C39 and a resistor R33 which are connected in parallel are also arranged between the negative input end of the operational amplifier IC14A and the output end of the operational amplifier IC 14A; the first control terminal of the operational amplifier IC14A is connected to the supply terminal 2V5 on the one hand and to signal ground via a capacitor C30 on the other hand, and the negative supply terminal of the operational amplifier IC14A is connected to signal ground via a capacitor C36 on the one hand and to the supply terminal-2V 5 on the other hand.
In fig. 2, RECEIVE is the original echo signal generated by the ultrasonic sensor, C39 and R33 are the feedback resistor and the feedback capacitor, and the amplification factor of the charge amplifier is: a=q/C39, Q being the amount of charge generated by the sensor.
As can be seen from the processing content in step 12, the specific processing content includes:
121. the echo signal is subjected to primary amplification treatment through a primary amplifier circuit;
122. and outputting the amplified signals to a PGA automatic gain circuit and a saturation amplifying circuit respectively for secondary amplification treatment to obtain amplified echo signals after secondary amplification.
The PGA automatic gain circuit for performing the gain processing in step 122, as shown in fig. 3, includes:
the operational amplifier IC14A, the reverse input end of the operational amplifier IC14A is used for receiving the amplified result outputted by the primary amplifier circuit, the forward input end of the operational amplifier IC14A is connected with analog ground, the first control end of the operational amplifier IC14A is connected with the power supply end 2V5, meanwhile, the second control end of the operational amplifier IC14A is connected with the power supply end-2V 5 through the capacitor C30 and is connected with the signal ground through the capacitor C36, a capacitor C39 and a resistor R33 which are connected in parallel are also arranged between the output end and the reverse input end of the comparator IC14A, the output end of the comparator IC14A is connected with the INMR pin of the programmable gain amplifier IC10 through the capacitor C390, and the INMR pin is simultaneously connected with the signal ground through the resistor R21;
pin inp of programmable gain amplifier IC10 is connected to signal ground through capacitor C22 and resistor R11 in turn, pin OFSN of programmable gain amplifier IC10 is connected to signal ground through capacitor C18, resistor R12 and resistor R13 in turn, resistor R12 is arranged between pin OFSN and pin VAGC, pin VBAT of programmable gain amplifier IC10 is connected to power supply terminal 3V0, simultaneously connected to signal ground through capacitor C170 and capacitor C17 in parallel, pin OFSN and pin VREF are connected to signal ground through capacitor C16 at the same time, pin EPAD is connected to digital ground, pins DETO and COMM of programmable gain amplifier IC10 are connected to signal ground,
pin OUTP of programmable gain amplifier IC10 is connected with pin 2 of operational amplifier IC12, a capacitor C26 is connected between pin OUTP and pin FBKP of programmable gain amplifier IC10, pin OUTM of programmable gain amplifier IC10 is connected with pin 3 of operational amplifier IC12, a capacitor C29 is connected between pin OUTM and pin FBKM of programmable gain amplifier IC10, pin 1 of operational amplifier IC12 is connected with signal ground, pin 7 of operational amplifier IC12 is connected with power supply end 2V5, and at the same time is connected with signal ground via capacitor C23, and pins 5 and 6 of operational amplifier IC12 are also connected with capacitor C28;
pin GAIN of programmable GAIN amplifier IC10 is connected to pin 1 of digital-to-analog converter IC13, pin 1 of IC13 is also connected to signal ground via resistor R28, pin 2 of IC13 is connected to signal ground, pin 3 of IC13 is connected to supply terminal 3V0, and simultaneously is also connected to signal ground via capacitor C33, pin 6 of IC13 is connected to signal ground, and pins 4, 5 of IC13 are connected to supply terminal 3V0 via resistors R31, R32, respectively.
The IC10 is a linear low-noise PGA with a maximum GAIN of 80dB, an operating frequency range of 18MHz, and the GAIN is controlled by the GAIN pin voltage, which generates a precise control voltage through the IC13 (DAC). IC12 is a single ended differential to unity gain operational amplifier.
The comparison processing procedure proposed in step 13 includes:
131. judging whether the waveform peak value of the amplified echo signal is in a preset interval in a comparator circuit;
132. if the intermediate value of the two wave peaks is calculated in the preset interval, setting the intermediate value as a compared threshold voltage through a DAC;
133. and if the DAC is regulated outside the preset interval, judging again based on the regulated waveform peak value.
When the method is operated for the first time, a proper gain value is preset for the PGA through the DAC, a proper threshold voltage is preset for the comparator through the DAC, during downstream measurement, the waveform of the echo is collected through the ADC, data analysis is carried out on the waveform, whether the magnitude of the echo is 650-750 mV or not is firstly judged, if not, the gain of the PGA is controlled to keep the waveforms under different conditions at 650-750 mV through adjusting the value of the DAC, then the peak value difference between the first wave and the second wave is analyzed through the data sampled by the DAC, the threshold voltage of the comparator is set to the middle level of the peak value of the first wave and the second wave, and therefore the threshold level is guaranteed to have enough margin to avoid false waves when the waveform shakes.
The comparison process proposed in step 132 is performed including a threshold comparison circuit and a zero-crossing detection circuit, wherein the threshold comparison circuit includes, as shown in fig. 4:
the reverse input end of the amplifier U11 is connected with signal ground through a resistor R204 and a resistor R22, one end of the resistor R22 far away from the signal ground is also connected with the output end TP58 of the PGA automatic gain circuit, the positive input end of the amplifier U11 is connected with the signal ground through a capacitor C201, two ends of the capacitor C201 are connected with a resistor R206 in parallel, and one end of the resistor R206 far away from the signal ground is also connected with a power supply end 3V0 through a resistor R205; the first control end of the amplifier U11 is connected with the power supply end 3V0, the first control end of the amplifier U11 is connected with signal ground through a capacitor C202 on one hand, and is connected with an offset pin on the other hand, the output end of the amplifier U11 is also connected with an AINP pin of the analog-to-digital converter U12 through a resistor R207, and the output end of the amplifier U11 is also connected with the reverse input end of the amplifier U11 through a resistor R203;
the AINP pin of the analog-digital converter U12 is also connected with signal ground through a capacitor C203, the AINM pin of the analog-digital converter U12 is grounded through a resistor R208, the SDO pin of the analog-digital converter U12 is connected with signal ground through a resistor R210 and a capacitor C205, the SCLK pin of the analog-digital converter U12 is connected with signal ground through a resistor R209 and a capacitor C205, the DVDD pin of the analog-digital converter U12 is connected with a power supply end 3V0 through a resistor R222, the AVDD pin of the analog-digital converter U12 is connected with a power supply end 3V0 through a resistor R223, and a capacitor C204 is connected between the AVDD pin and the GND pin of the analog-digital converter U12 in parallel; the AINP pin of the analog-to-digital converter U12 is also connected with the positive input end of the comparator IC7A through a capacitor C211;
the first control end of the comparator IC7A is connected with the power supply end 2V5 on one hand, and is also connected with signal ground through a capacitor C90 on the other hand, the second control end of the comparator IC7A is connected with the signal ground through a capacitor C9 on the other hand, and is connected with the power supply end-2V 5, and the output end of the comparator IC7A is sequentially connected with the signal ground through resistors R16 and R8; the reverse input end of the comparator IC7A is connected with the pin 1 of the digital-to-analog converter U10 through a resistor R211, the pin 2 and the pin 6 of the digital-to-analog converter U10 are connected with signal ground, the pin 3 of the digital-to-analog converter U10 is connected with the signal ground through a capacitor C206, two ends of the capacitor C206 are connected with a capacitor C226 in parallel, and the other end of the capacitor C206 far away from the grounding end is connected with a power supply end 3V0.
Where TP58 is the PGA output waveform, U11 is a unity gain amplifier, where mainly ADC is used as input buffer to adjust the impedance. The gain may be adjusted by R203 and R204. U12 is an ADC with the highest sampling frequency reaching 3MHz, the data of the echo is sampled by the ADC, the MCU can perform data analysis to ensure that the control gain keeps the peak value of the echo between 650 mV and 750mV, meanwhile, the intermediate level of the peak value of the first wave and the second wave can be analyzed, and the value is set as the threshold voltage of the comparator (IC 7) through U10 (DAC).
Optionally, the zero-crossing detection comparator circuit comprises
The reverse input end of the comparator IC5A is connected with the output end TP51 of the primary amplifier circuit through a resistor R14 and a capacitor C24, and the forward input end of the comparator IC5A is connected with one end of the capacitor C24 far away from TP51 through a resistor R15 on one hand and connected with signal ground on the other hand; a first control end of the comparator IC5A is connected with the power supply end 2V5, and a second control end of the comparator IC5A is connected with the power supply end-2V 5 and is grounded with signals through a capacitor C19; the output end of the comparator IC5A is electrically connected with the positive input end of the comparator IC7B through a capacitor C8;
the positive input end of the comparator IC7B is grounded through a resistor R3, the output end of the comparator IC7B is connected with the emitter of the triode Q1, the base electrode of the triode Q1 is grounded through a resistor R9, and a resistor R10 is connected in parallel between the base electrode and the emitter of the triode Q1; the collector of the triode Q1 is connected with a signal end TP61, and a resistor R6 and a capacitor C12 which are connected in parallel are arranged between the signal end TP61 and the signal ground.
Where TP51 is the primary amplifier output coupled into IC5 through C24, the IC gain is controlled by R14 and R4 where the gain is as large as possible, preferably the first echo saturation in the output waveform. When a zero-crossing comparator is used to generate a STOP signal, the generated pulse signal is influenced by the magnitude of the input signal, the larger the signal is, the closer the slope at the zero crossing is to 90 degrees, so that the smaller the error is, and therefore, the design of a saturation amplifying circuit is required to be increased.
Optionally, the step of obtaining the STOP signal based on the compared signals includes:
the STOP signal circuit masks interference due to noise based on the output result, and an adjusted STOP signal is obtained. The STOP signal generated by the threshold comparator, and also the STOP signal generated after zero crossing of the comparator, is known to have smaller error (slope approaching 90 °); however, the zero-crossing detection will generate output pulses along with noise in the signal, so that we cannot judge the actual STOP signal, so we need to add a circuit for selecting the zero-crossing STOP signal by using the threshold STOP signal, and then give the GP22 chip to perform time-of-flight detection.
As shown in fig. 5, the STOP signal circuit includes:
a monostable resonator IC9, in which a STOP2 signal generated by the threshold comparator circuit is received at a pin 2 of the monostable resonator IC9, a pin 7 of the monostable resonator IC9 is connected to a power supply terminal 2V5 via a resistor R17, a pin 6 of the monostable resonator IC9 is connected to signal ground on the one hand, and is connected to the pin 7 via a capacitor C20 on the other hand, and a pin 8 of the monostable resonator IC9 is connected to the power supply terminal 2V5 on the one hand, and is connected to signal ground via a capacitor C371 on the other hand; the pin 5 of the monostable resonator IC9 is provided with an output TP59, the output TP59 is connected to a first input of the and-gate chip IC1, a second input of the and-gate chip IC1 is configured to receive the STOP1 signal generated by the zero-crossing comparator, the first control of the and-gate chip IC1 is connected to the power supply terminal 2V5 on the one hand, and to the ground via the capacitor C373, the second control of the and-gate chip IC1 is connected to the ground, and the output of the and-gate chip IC1 is connected to the output TP62 for outputting the adjusted STOP signal.
In the implementation, the IC9 is a monostable resonator, the input trigger signal is a STOP2 signal generated by a threshold comparator, and the pulse width of the TP59 output end is controlled by R17 and C20; the IC is an AND gate chip and performs AND operation on the STOP1 signal generated by the zero-crossing comparator and the output of the resonator, and because the phases of STOP generated by the two paths are basically consistent, the STOP signal generated by noise can be well shielded when the monostable waveform generated by the STOP2 is in AND operation with the STOP1, so that the correct STOP signal can be obtained.
Based on the processing principle of step 13 and the schematic circuit structures described above, a processing flow including the foregoing circuit is also provided as shown in fig. 6, where the GP22 module performs a final gas flow metering flow according to the processed STOP signal.
The GP22 module adopts GP22 as a TDC timing chip, MSP430F5419 is selected as an MCU controller, the resonance frequency of an ultrasonic sensor is 220kHz, and the ultrasonic flow passage L=70mm. During forward flow measurement, the GP22 generates FIRE driving pulse, after passing through the ultrasonic driving circuit, the forward flow sensor is driven by the ultrasonic driving module through the switch module 1, the ultrasonic echo signal generated by the reverse flow sensor is transmitted to the ultrasonic signal processing module circuit through the switch module 2, and then the ultrasonic echo signal is returned to the GP22 for time measurement. During counter flow measurement, the GP22 generates FIRE driving pulse, the counter flow sensor is driven by the ultrasonic driving module after passing through the ultrasonic driving circuit, at the moment, the forward flow sensor generates ultrasonic echo signals and transmits the ultrasonic echo signals to the ultrasonic signal processing module circuit, and the ultrasonic echo signals are returned to the GP22 for time measurement. And after the forward flow and the backward flow flight time are measured, calculating the flow passing through the flow channel according to a time difference method.
The various numbers in the above embodiments are for illustration only and do not represent the order of assembly or use of the various components.
The foregoing is illustrative of the present application and is not to be construed as limiting thereof, but rather, the present application is to be construed as limited to the appended claims.
Claims (5)
1. The flow calibration method for the ultrasonic gas meter is characterized by comprising the following steps of:
receiving driving pulses output by a micro control unit, controlling a first ultrasonic transducer to emit ultrasonic signals based on the driving pulses, and generating echo signals by receiving the ultrasonic signals by a second ultrasonic transducer corresponding to the first ultrasonic transducer;
the echo signal is subjected to primary amplification treatment through a primary amplifier circuit;
the amplified signals are respectively output to a PGA automatic gain circuit and a saturation amplifying circuit for secondary amplification treatment, and amplified echo signals after secondary amplification are obtained;
transmitting the amplified echo signals after the PGA automatic gain circuit and the saturation amplification circuit perform secondary amplification processing to a comparator circuit to obtain compared signals output by the comparator circuit;
obtaining a STOP signal based on the compared signals;
the comparator circuit comprises a threshold comparator circuit, the amplified echo signal after the PGA automatic gain circuit is subjected to the secondary amplification is transmitted to the comparator circuit, and a compared signal output by the comparator circuit is obtained, and the method comprises the following steps:
judging whether the waveform peak value of the echo signal amplified by the PGA automatic gain circuit is in a preset interval or not in the threshold comparator circuit to obtain a compared signal output by the threshold comparator circuit; if the intermediate value of the two wave peaks is calculated in the preset interval, setting the intermediate value as a compared threshold voltage through a DAC; if the peak value difference is outside the preset interval, DAC adjustment is carried out, and the peak value difference is processed by means of ADC sampling processing mode; the threshold comparator circuit includes: the amplifier U11 is used for buffering the input of the analog-to-digital converter U12 and adjusting the impedance; the analog-to-digital converter U12 is used for collecting the amplified echo signals; a comparator IC7A for comparing the amplified echo signal with the threshold voltage;
the comparator circuit also comprises a zero-crossing detection comparator circuit, the amplified echo signal after the saturation amplification circuit performs secondary amplification processing is transmitted to the comparator circuit, and a compared signal output by the comparator circuit is obtained, and the comparator circuit comprises:
transmitting the amplified echo signal after the saturation amplification circuit performs secondary amplification treatment to a zero-crossing detection comparator circuit to obtain a compared signal output by the zero-crossing detection comparator circuit;
the step of obtaining a STOP signal based on the compared signals includes:
based on the compared signal output by the zero-crossing detection comparator circuit and the compared signal output by the threshold comparator circuit, a STOP signal is obtained;
the flow calibration method further comprises the following steps:
analyzing the STOP signal and comparing the STOP signal with the echo signal so that the head wave of the STOP signal is consistent with the head wave of the echo signal;
the amplified signals are respectively output to a PGA automatic gain circuit and a saturation amplifying circuit for secondary amplification treatment to obtain amplified echo signals after secondary amplification, and the method comprises the following steps:
performing secondary amplification processing on the amplified echo signal after primary amplification in a PGA automatic gain circuit to obtain an amplified echo signal; and
amplifying the first-stage amplified echo signal in a saturation amplifying circuit to obtain an amplified echo signal;
the PGA automatic gain circuit includes:
the operational amplifier IC14A, the reverse input end of the operational amplifier IC14A is used for receiving the amplified result outputted by the primary amplifier circuit, the forward input end of the operational amplifier IC14A is connected with analog ground, the first control end of the operational amplifier IC14A is connected with the power supply end 2V5, meanwhile, the second control end of the operational amplifier IC14A is connected with the power supply end-2V 5 through the capacitor C30 and is connected with the signal ground through the capacitor C36, a capacitor C39 and a resistor R33 which are connected in parallel are also arranged between the output end and the reverse input end of the comparator IC14A, the output end of the comparator IC14A is connected with the INMR pin of the programmable gain amplifier IC10 through the capacitor C390, and the INMR pin is simultaneously connected with the signal ground through the resistor R21;
pin inp of programmable gain amplifier IC10 is connected to signal ground through capacitor C22 and resistor R11 in turn, pin OFSN of programmable gain amplifier IC10 is connected to signal ground through capacitor C18, resistor R12 and resistor R13 in turn, resistor R12 is arranged between pin OFSN and pin VAGC, pin VBAT of programmable gain amplifier IC10 is connected to power supply terminal 3V0, simultaneously connected to signal ground through capacitor C170 and capacitor C17 in parallel, pin OFSN and pin VREF are connected to signal ground through capacitor C16 at the same time, pin EPAD is connected to digital ground, pins DETO and COMM of programmable gain amplifier IC10 are connected to signal ground,
pin OUTP of programmable gain amplifier IC10 is connected with pin 2 of operational amplifier IC12, a capacitor C26 is connected between pin OUTP and pin FBKP of programmable gain amplifier IC10, pin OUTM of programmable gain amplifier IC10 is connected with pin 3 of operational amplifier IC12, a capacitor C29 is connected between pin OUTM and pin FBKM of programmable gain amplifier IC10, pin 1 of operational amplifier IC12 is connected with signal ground, pin 7 of operational amplifier IC12 is connected with power supply end 2V5, and at the same time is connected with signal ground via capacitor C23, and pins 5 and 6 of operational amplifier IC12 are also connected with capacitor C28;
pin GAIN of programmable GAIN amplifier IC10 is connected to pin 1 of digital-to-analog converter IC13, pin 1 of IC13 is also connected to signal ground via resistor R28, pin 2 of IC13 is connected to signal ground, pin 3 of IC13 is connected to supply terminal 3V0, and simultaneously is also connected to signal ground via capacitor C33, pin 6 of IC13 is connected to signal ground, and pins 4, 5 of IC13 are respectively connected to supply terminal 3V0 via resistors R31, R32.
2. The flow calibration method for an ultrasonic gas meter according to claim 1, wherein,
the reverse input end of the amplifier U11 is connected with signal ground through a resistor R204 and a resistor R22, one end of the resistor R22 far away from the signal ground is also connected with an output end TP58 of the PGA automatic gain circuit, the forward input end of the amplifier U11 is connected with the signal ground through a capacitor C201, two ends of the capacitor C201 are connected with a resistor R206 in parallel, and one end of the resistor R206 far away from the signal ground is also connected with a power supply end 3V0 through a resistor R205; the first control end of the amplifier U11 is connected with the power supply end 3V0, the first control end of the amplifier U11 is connected with signal ground through a capacitor C202 on one hand, and is connected with an offset pin on the other hand, the output end of the amplifier U11 is also connected with an AINP pin of the analog-to-digital converter U12 through a resistor R207, and the output end of the amplifier U11 is also connected with the reverse input end of the amplifier U11 through a resistor R203;
the AINP pin of the analog-digital converter U12 is also connected with signal ground through a capacitor C203, the AINM pin of the analog-digital converter U12 is grounded through a resistor R208, the SDO pin of the analog-digital converter U12 is connected with signal ground through a resistor R210 and a capacitor C205, the SCLK pin of the analog-digital converter U12 is connected with signal ground through a resistor R209 and a capacitor C205, the DVDD pin of the analog-digital converter U12 is connected with a power supply end 3V0 through a resistor R222, the AVDD pin of the analog-digital converter U12 is connected with a power supply end 3V0 through a resistor R223, and a capacitor C204 is connected between the AVDD pin and the GND pin of the analog-digital converter U12 in parallel; the AINP pin of the analog-to-digital converter U12 is also connected with the positive input end of the comparator IC7A through a capacitor C211;
the first control end of the comparator IC7A is connected with the power supply end 2V5 on one hand, and is also connected with signal ground through a capacitor C90 on the other hand, the second control end of the comparator IC7A is connected with the signal ground through a capacitor C9 on the other hand, and is connected with the power supply end-2V 5, and the output end of the comparator IC7A is sequentially connected with the signal ground through resistors R16 and R8; the reverse input end of the comparator IC7A is connected with the pin 1 of the digital-to-analog converter U10 through a resistor R211, the pin 2 and the pin 6 of the digital-to-analog converter U10 are connected with signal ground, the pin 3 of the digital-to-analog converter U10 is connected with the signal ground through a capacitor C206, two ends of the capacitor C206 are connected with a capacitor C226 in parallel, and the other end of the capacitor C206 far away from the grounding end is connected with a power supply end 3V0.
3. The flow calibration method for an ultrasonic gas meter of claim 1, wherein the zero-crossing detection comparator circuit comprises:
the reverse input end of the comparator IC5A is connected with the output end TP51 of the primary amplifier circuit through a resistor R14 and a capacitor C24, and the forward input end of the comparator IC5A is connected with one end of the capacitor C24 far away from TP51 through a resistor R15 on one hand and connected with signal ground on the other hand; a first control end of the comparator IC5A is connected with the power supply end 2V5, and a second control end of the comparator IC5A is connected with the power supply end-2V 5 and is grounded with signals through a capacitor C19; the output end of the comparator IC5A is electrically connected with the positive input end of the comparator IC7B through a capacitor C8;
the positive input end of the comparator IC7B is grounded through a resistor R3, the output end of the comparator IC7B is connected with the emitter of the triode Q1, the base electrode of the triode Q1 is grounded through a resistor R9, and a resistor R10 is connected in parallel between the base electrode and the emitter of the triode Q1; the collector of the triode Q1 is connected with a signal end TP61, and a resistor R6 and a capacitor C12 which are connected in parallel are arranged between the signal end TP61 and the signal ground.
4. The flow calibration method for an ultrasonic gas meter according to claim 1, wherein the deriving the STOP signal determining the echo signal time based on the compared signals comprises:
the STOP signal circuit masks the interference caused by noise based on the output result, and an adjusted STOP signal is obtained.
5. The flow calibration method for an ultrasonic gas meter of claim 1, wherein the STOP signal circuit comprises:
a monostable resonator IC9, in which a STOP2 signal generated by the threshold comparator circuit is received at a pin 2 of the monostable resonator IC9, a pin 7 of the monostable resonator IC9 is connected to a power supply terminal 2V5 via a resistor R17, a pin 6 of the monostable resonator IC9 is connected to signal ground on the one hand, and is connected to the pin 7 via a capacitor C20 on the other hand, and a pin 8 of the monostable resonator IC9 is connected to the power supply terminal 2V5 on the one hand, and is connected to signal ground via a capacitor C371 on the other hand;
the pin 5 of the monostable resonator IC9 is provided with an output TP59, the output TP59 is connected to a first input of the and-gate chip IC1, a second input of the and-gate chip IC1 is configured to receive the STOP1 signal generated by the zero-crossing comparator, the first control of the and-gate chip IC1 is connected to the power supply terminal 2V5 on the one hand, and to the ground via the capacitor C373, the second control of the and-gate chip IC1 is connected to the ground, and the output of the and-gate chip IC1 is connected to the output TP62 for outputting the adjusted STOP signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911358973.1A CN111121894B (en) | 2019-12-25 | 2019-12-25 | Flow calibration method for ultrasonic gas meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911358973.1A CN111121894B (en) | 2019-12-25 | 2019-12-25 | Flow calibration method for ultrasonic gas meter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111121894A CN111121894A (en) | 2020-05-08 |
| CN111121894B true CN111121894B (en) | 2023-10-20 |
Family
ID=70502437
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911358973.1A Active CN111121894B (en) | 2019-12-25 | 2019-12-25 | Flow calibration method for ultrasonic gas meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111121894B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112147620A (en) * | 2020-09-25 | 2020-12-29 | 上海应用技术大学 | System and method for measuring ultrasonic flight time in pipeline |
| CN112747797A (en) * | 2020-12-31 | 2021-05-04 | 金卡智能集团股份有限公司 | Flow metering circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4114233A1 (en) * | 1991-04-26 | 1992-11-05 | Flexim Flexible Industriemesst | Ultrasonic flow measurement system - performs measurements in different diffusion directions and flow speed is determined from transit time difference using ultrasonic signal converters |
| CN205748511U (en) * | 2015-12-30 | 2016-11-30 | 天津市迅尔自控设备制造有限公司 | Front-end analog circuit for gas ultrasonic flowmeter converter |
| CN107131918A (en) * | 2017-07-02 | 2017-09-05 | 中国计量大学 | A kind of low-consumption ultrasonic flow measurement meter echo signal processing method and circuit |
| CN109186693A (en) * | 2018-08-02 | 2019-01-11 | 电子科技大学 | A kind of detection of the backscatter signal circuit of self-adapting ultrasonic |
| CN110346002A (en) * | 2019-07-23 | 2019-10-18 | 电子科技大学 | A kind of Ultrasonic Wave Flowmeter signal processing and conversion circuit |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140096586A1 (en) * | 2012-10-06 | 2014-04-10 | Spire Metering Technology LLC | Device and method for measurement of ultrasonic transit times |
| JP6957278B2 (en) * | 2017-09-08 | 2021-11-02 | ローム株式会社 | Ultrasonic flowmeter |
-
2019
- 2019-12-25 CN CN201911358973.1A patent/CN111121894B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4114233A1 (en) * | 1991-04-26 | 1992-11-05 | Flexim Flexible Industriemesst | Ultrasonic flow measurement system - performs measurements in different diffusion directions and flow speed is determined from transit time difference using ultrasonic signal converters |
| CN205748511U (en) * | 2015-12-30 | 2016-11-30 | 天津市迅尔自控设备制造有限公司 | Front-end analog circuit for gas ultrasonic flowmeter converter |
| CN107131918A (en) * | 2017-07-02 | 2017-09-05 | 中国计量大学 | A kind of low-consumption ultrasonic flow measurement meter echo signal processing method and circuit |
| CN109186693A (en) * | 2018-08-02 | 2019-01-11 | 电子科技大学 | A kind of detection of the backscatter signal circuit of self-adapting ultrasonic |
| CN110346002A (en) * | 2019-07-23 | 2019-10-18 | 电子科技大学 | A kind of Ultrasonic Wave Flowmeter signal processing and conversion circuit |
Non-Patent Citations (4)
| Title |
|---|
| Wen-Jiao Zhu.Variable ratio threshold and zero-crossing detection based signal processing method for ultrasonic gas flow meter.Measurement.2017,第第103卷卷全文. * |
| 唐美芹 等.基于MSP430的无磁热量表设计及实现.《自动化与仪表》.2009,(第12期), * |
| 汪伟.一种气体超声波流量计信号处理方法研究.《电子测量与仪器学报》.2015,第29卷(第9期), * |
| 鲁克华.基于分段包络互相关算法的气体超声波流量计研究.《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》.2019,(第5期), * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111121894A (en) | 2020-05-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10775212B2 (en) | Ultrasonic flow meter | |
| US10088348B2 (en) | Ultrasonic gas flow meter based on FPGA and DSP | |
| CN111121894B (en) | Flow calibration method for ultrasonic gas meter | |
| CN109579950B (en) | Mistake proofing ripples detection device of gaseous ultrasonic flowmeter | |
| CN211717569U (en) | Flow calibration circuit for ultrasonic gas meter | |
| EP2383550A1 (en) | Ultrasonic flow meter | |
| CN107131918B (en) | Echo signal processing method and circuit of low-power-consumption ultrasonic flowmeter | |
| CN205037931U (en) | High accuracy ultrasonic wave gas flowmeter | |
| CN105115553A (en) | High-accuracy ultrasonic gas flow meter based on time-difference method | |
| CN116625444A (en) | Method for self-adapting characteristic wave and flow correction of ultrasonic water meter | |
| Zheng et al. | Research and realization of ultrasonic gas flow rate measurement based on ultrasonic exponential model | |
| CN113558659B (en) | High-precision ultrasonic lung function detector and detection method thereof | |
| CN104535140A (en) | Resonant frequency testing method for energy converter of ultrasonic flowmeter | |
| CN213903643U (en) | Signal output control device | |
| CN112019989B (en) | Dynamic performance testing device for ultrasonic transducer | |
| RU2353905C1 (en) | Method for measurement of liquid mediums flow and ultrasonic flow metre | |
| CN116358652A (en) | Multi-feature point ultrasonic transit time measurement method based on cross-correlation algorithm assistance | |
| CN105157772B (en) | Timer expiration method and circuit and ultrasonic wave detecting system based on the circuit | |
| CN114623890A (en) | Gas ultrasonic flowmeter and wave-jumping identification correction method thereof | |
| CN202057365U (en) | Ultrasonic wave advance-signal self-adapting circuit under pressure variation state | |
| CN113932861A (en) | Ultrasonic sampling window self-adaptive adjustment method and ultrasonic gas meter | |
| CN204216856U (en) | A kind of automatic gain control circuit being applied to ultrasonic calorimeter | |
| CN103099620A (en) | High-accuracy respiratory monitor | |
| CN109724655A (en) | A kind of Ultrasonic Wave Flowmeter signal processing system | |
| CN114690102A (en) | Time-varying current generation device, parameter calibration system and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20230830 Address after: 325600 291 weft seventeen Road, Yueqing Economic Development Zone, Wenzhou, Zhejiang Applicant after: Goldcard Smart Group Co.,Ltd. Applicant after: Tancy Instrument Group Co.,Ltd. Address before: 325600 291 weft seventeen Road, Yueqing Economic Development Zone, Wenzhou, Zhejiang Applicant before: Goldcard Smart Group Co.,Ltd. |
|
| GR01 | Patent grant | ||
| GR01 | Patent grant |