Multi-channel ultrasonic water flow velocity and flow measuring circuit

Abstract

The invention discloses a multichannel ultrasonic water flow velocity and flow measuring circuit. On the basis of an analog switch switching circuit module, two analog switches are respectively used for realizing switching from a transmitting circuit to an ultrasonic transducer A and an ultrasonic transducer B, and the other two analog switches are respectively used for realizing switching from a receiving circuit to the ultrasonic transducer A and the ultrasonic transducer B; the ultrasonic transducer A and the ultrasonic transducer B are both ultrasonic transducers in 16 bidirectional transceiving channels, and ultrasonic water flow velocity measurement of 32 channels is achieved by calculating the time difference between the time when the forward and reverse water ultrasonic transmitting circuit module transmits signals to start timing and the time when the ultrasonic receiving circuit module receives the signals to stop timing and combining the width of the water channel. Measuring flow velocities at different water depths of the cross section of the canal; through cooperation with an algorithm, accurate measurement of water flow velocity and flow is realized. The device has the advantages of being low in cost, high in precision, easy to operate, multi-channel and convenient to carry.

Description

Technical Field

[0001] The invention belongs to the technical field of signal acquisition and measurement and control, and relates to a multi-channel ultrasonic water flow velocity and flow measurement circuit. Background Art

[0002] Irrigation canals are a key component of agricultural irrigation systems. Accurately measuring irrigation canal flow is essential for efficient use of water resources and effective management of irrigation activities. Accurately measuring irrigation canal flow can help farmers, irrigation system managers and related institutions better manage water resources, achieve a balance between water supply and demand, and thus improve irrigation efficiency and crop yields. Although ultrasound has a wide range of applications in flow measurement, there are still some problems in measuring agricultural irrigation canal flow, such as low measurement accuracy, high price, complex measurement operation, and difficulty in popularization and application. Therefore, it is necessary to further develop and improve measurement technology, improve measurement accuracy and simplify the measurement process to meet the actual needs of agricultural irrigation canal flow measurement. Therefore, flow meters with high accuracy, low price, simple operation and easy portability have a wide range of applications.

[0003] The multi-channel ultrasonic water flow velocity and flow measurement designed by the present invention is a method for measuring flow velocity based on the principle that the time difference required for ultrasonic waves to pass through a liquid medium is different, that is, the time required for ultrasonic waves to pass through a water body in the downstream direction is shorter than that in the upstream direction. Ultrasonic flow velocity measurement has revealed a new method for measuring water flow velocity and flow, which plays a vital role in agricultural production such as agricultural irrigation. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a multi-channel ultrasonic water flow rate and flow measurement circuit. The multi-channel ultrasonic water flow rate and flow measurement circuit based on the STM32F4 processor uses the principle of different time differences required for ultrasonic waves to pass through liquid media to measure flow rate and flow. The purpose is to provide a low-cost, high-precision, easy-to-operate, multi-channel ultrasonic water flow rate and flow measurement instrument.

[0005] The multi-channel ultrasonic water flow rate and flow measurement circuit of the present invention comprises a main control circuit module, a data storage circuit module, an ultrasonic transmission circuit module, an analog switch switching circuit module, an ultrasonic receiving circuit module, a TDC timing circuit module, and a 485 communication circuit module; wherein: the main control circuit module is electrically connected to the data storage circuit module, the analog switch switching circuit module, the TDC timing circuit module, and the 485 communication circuit module; the analog switch switching circuit module is electrically connected to the ultrasonic transmission circuit module and the ultrasonic receiving circuit module; the ultrasonic transmission circuit module is electrically connected to the ultrasonic transducer A and the ultrasonic transducer B, and the ultrasonic receiving circuit module is electrically connected to the ultrasonic transducer A and the ultrasonic transducer B;

[0006] in:

[0007] The main control circuit module is used to generate a 1MHz PWM signal, calculate the water flow rate and flow rate, and control other circuit modules to work in coordination;

[0008] The data storage circuit module is used to store data, including channel width, time difference, water flow speed and flow rate;

[0009] The ultrasonic transmitting circuit module is used to boost the 1MHz PWM signal and drive the ultrasonic transducer A and the ultrasonic transducer B to transmit ultrasonic waves;

[0010] The analog switch switching circuit module is used for switching the ultrasonic transducer A, the ultrasonic transducer B, the ultrasonic transmitting circuit module and the ultrasonic receiving circuit module;

[0011] The ultrasonic receiving circuit module is used to receive the ultrasonic echo signal sent by the ultrasonic transmitting circuit module and perform second-order active filtering and amplification processing;

[0012] The TDC timing circuit module is used for measuring and calculating the ultrasonic time difference;

[0013] The 485 communication circuit module is used for exchanging data with the host computer and updating the program.

[0014] The main control circuit module specifically includes:

[0015] The STM32 microprocessor and peripheral circuits are used to generate 1MHz PWM signals, calculate water flow rate and flow rate, and control other circuit modules to work together.

[0016] The ultrasonic transmitting circuit module is electrically connected to ultrasonic transducer A and ultrasonic transducer B through an analog switch switching circuit; the ultrasonic transmitting circuit module is an amplifier circuit composed of a triode, which is used to boost the 1MHz PWM signal and drive the 1MHz ultrasonic transducer A and ultrasonic transducer B to transmit ultrasonic waves.

[0017] The ultrasonic receiving circuit module has two paths, namely ultrasonic receiving circuit 1 and ultrasonic receiving circuit 2; the ultrasonic receiving circuit module includes:

[0018] Operational amplifier, used for second-order active filtering and amplification processing of ultrasonic echo signals;

[0019] Comparator, used for reprocessing the ultrasonic echo signal after passing through the operational amplifier.

[0020] The analog switch switching circuit module specifically includes:

[0021] Control the enable signal and address selection signal line of the analog switch switching circuit module;

[0022] Four analog switches, two of which are used to realize the switching of the ultrasonic transmitting circuit module to the ultrasonic transducer A and the ultrasonic transducer B, and the other two are used to realize the switching of the ultrasonic receiving circuit module to the ultrasonic transducer A and the ultrasonic transducer B; the ultrasonic transducer A and the ultrasonic transducer B are both ultrasonic transducers in the 16-way bidirectional transmitting and receiving channels.

[0023] The TDC timing circuit module specifically includes:

[0024] TDC7201 and an external 8MHz clock are used to measure the ultrasonic transmission time in downstream and upstream water, with a measurement range of 12ns to 2000ns in mode 1, 250ns to 8ms in mode 2, and 0.25ns to 8ms in combined mode.

[0025] The 485 communication circuit module specifically includes:

[0026] SP3485 and peripheral circuits are used to exchange data with the host computer and to update the program.

[0027] The multi-channel ultrasonic water velocity and flow measurement circuit comprises the following working steps:

[0028] Step 1: Initialize the STM32 microprocessor of the main control circuit module and the TDC timing circuit module;

[0029] Step 2: The STM32 microprocessor controls the analog switch to switch the channels relative to the two ultrasonic transducers A and B to the ultrasonic transmitting circuit module;

[0030] Step 3: The TDC timing circuit module sends a trigger signal to the STM32 microprocessor of the main control circuit module;

[0031] Step 4: The STM32 microprocessor of the main control circuit module receives the trigger signal, sends a PWM signal to drive ultrasonic transducer A and ultrasonic transducer B at the same time, and sends a RE_START signal to the TDC timing circuit module, and the TDC timing circuit module starts working and timing;

[0032] Step 5: After the STM32 microprocessor of the main control circuit module sends the specified number of PWM signals, it controls the analog switch to switch the measurement channel relative to the two ultrasonic transducers A and B to the ultrasonic receiving circuit module;

[0033] Step 6: After receiving the signal, the echo circuits of the two-way ultrasonic transducer A and the ultrasonic transducer B simultaneously send the signal to the TDC timing circuit module, and the TDC timing circuit module calculates the ultrasonic transmission time of the downstream and upstream;

[0034] Step 7: The TDC timing circuit module sends an interrupt to the STM32 microprocessor of the main control circuit module. The main control circuit module reads the data of the TDC timing circuit module through SPI, and calculates the time difference of ultrasonic transmission in the downstream and upstream directions and the water flow rate;

[0035] Step 8: Return to step 2 and measure the next channel;

[0036] Step 9: After measuring the water flow rates of all 16 channels, the STM32 microprocessor of the main control circuit module calculates the average flow rate and total flow rate;

[0037] Step 10: Return to step 1 and measure again.

[0038] The working principle of the present invention is as follows:

[0039] The working principle of ultrasonic time difference method for measuring flow velocity is as follows Figure 2 As shown in the figure, the propagation speed of ultrasound is faster in the direction of water flow, and slower in the direction against water flow. The water flow velocity is calculated using the propagation time difference of ultrasonic signals. Ultrasonic waves are emitted simultaneously by ultrasonic transducers at both ends. After emitting the ultrasonic signal, the transducers are immediately switched from analog switches to ultrasonic receiving circuits. The ultrasonic transducers at both ends stop when they receive echoes. Assuming that the width of the canal is L, the flow rate of water is v, the propagation speed of ultrasound in still water is c, the angle between the propagation direction of ultrasound and the flow rate v is θ, the propagation time of ultrasound in the water is T, and the propagation time in the water against water is t2.

[0040] but:

[0041] Thus we get: Since c>>v, it can be simplified to: Eliminating the propagation speed c of ultrasonic waves in water, we can obtain

[0042] Simplified, we can get

[0043] The multi-channel ultrasonic water flow rate and flow measurement circuit described in the present invention has the beneficial effects that: the present invention is based on an analog switch switching circuit module, four analog switches, two of which are used to realize the switching of the sending circuit to ultrasonic transducer A and ultrasonic transducer B, and the other two are used to realize the switching of the receiving circuit to ultrasonic transducer A and ultrasonic transducer B, respectively. The ultrasonic transducer A and ultrasonic transducer B are both ultrasonic transducers in 16-way bidirectional transceiver channels. By calculating the time difference between the start timing of the signal sent by the forward and reverse water ultrasonic sending circuit module and the stop timing of the signal received by the ultrasonic receiving circuit module, combined with the channel width, 32-channel ultrasonic water flow velocity measurement is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall structure;

[0045] Figure 2 This is a schematic diagram of the speed measurement principle using the time difference method;

[0046] Figure 3 This is a schematic diagram of one circuit of the ultrasonic transmitting circuit module;

[0047] Figure 4 It is a schematic diagram of the analog switch switching circuit module;

[0048] Figure 5 This is a schematic diagram of one circuit of the ultrasonic receiving circuit module;

[0049] Figure 6 It is the circuit schematic diagram of the TDC timing circuit module;

[0050] Figure 7 This is a schematic diagram of the ultrasonic flow velocity measurement workflow. DETAILED DESCRIPTION

[0051] Example 1

[0052] The multi-channel ultrasonic water flow rate and flow measurement circuit of the present invention is as follows: Figure 1As shown, it includes a main control circuit module, a data storage circuit module, an ultrasonic transmitting circuit module, an analog switch switching circuit module, an ultrasonic receiving circuit module, a TDC timing circuit module, and a 485 communication circuit module; wherein: the main control circuit module is electrically connected to the data storage circuit module, the analog switch switching circuit module, the TDC timing circuit module, and the 485 communication circuit module; the analog switch switching circuit module is electrically connected to the ultrasonic transmitting circuit module and the ultrasonic receiving circuit module; the ultrasonic transmitting circuit module is electrically connected to the ultrasonic transducer A and the ultrasonic transducer B, and the ultrasonic receiving circuit module is electrically connected to the ultrasonic transducer A and the ultrasonic transducer B. The circuit modules are electrically connected to the ultrasonic transducer A and the ultrasonic transducer B respectively; the present invention uses the TDC7201 chip as a component for measuring the flight time, based on analog switch switching, two of which are respectively used to realize the switching of one sending circuit to 16-channel ultrasonic transducers, and the other two are respectively used to realize the switching of another receiving circuit to 16-channel ultrasonic transducers. By calculating the time difference between the start timing of the ultrasonic transducer sending a signal and the stop timing of the ultrasonic transducer receiving a signal, combined with the canal width, 32-channel ultrasonic water flow velocity measurement can be realized, and finally the measurement of the canal water flow velocity is realized.

[0053] The working process of the present invention is as follows:

[0054] The circuit of the ultrasonic transmitting circuit module is as follows Figure 3 As shown, it includes resistors R17, R26, R27, R91, R93, R95, R103, capacitor C94 and transistor Q3, one end of resistor R26 is connected to the PWM input signal, and the other end is connected to pin 1 of transistor Q3, capacitor C94 is connected in parallel with resistor R26, resistor R93 is connected in parallel with pins 1 and 2 of transistor Q3, pin 2 of transistor Q3 is connected to ground, resistors R91 and R95 are connected in parallel, one end of which is connected to VCC12V, and the other end is connected to pin 3 of transistor Q3 and to one end of resistor R27.

[0055] The transistor Q3 is an NPN transistor.

[0056] The analog switch switching circuit module specifically includes:

[0057] Control the enable signal and address selection signal line of the analog switch switching circuit module;

[0058] Four analog switches, two of which are used to switch the ultrasonic transmitting circuit module to the ultrasonic transducer A and the ultrasonic transducer B, and the other two are used to switch the ultrasonic receiving circuit module to the ultrasonic transducer A and the ultrasonic transducer B; the ultrasonic transducer A and the ultrasonic transducer B are both ultrasonic transducers in the 16-way bidirectional transceiver channel.

[0059] The analog switch switching circuit module part circuit, such as Figure 4 As shown, 16 channels including 4 analog switches are respectively connected to ultrasonic transducer A (PA1-PA16) and ultrasonic transducer B (PB1-PB16), analog switch address selection A0-A4 and analog switch enable signal EN1-EN4 are connected to the STM32 microprocessor of the main control circuit module, and the STM32 microprocessor of the main control circuit module controls the analog switch to switch to connect with the ultrasonic transmitting circuit T1+ or the analog switch to connect with the ultrasonic receiving circuit Receive1.

[0060] The ultrasonic receiving circuit module is used to receive ultrasonic echo signals and perform second-order active filtering and amplification processing.

[0061] One of the ultrasonic receiving circuit modules is as follows: Figure 5 As shown, it includes a resistor, a capacitor, a transistor Q5, an operational amplifier U15, a diode D6, a diode D7, and a comparator U14. The analog switch switches to connect the ultrasonic receiving echo Receive1 to one end of the capacitor C64, the other end of the capacitor C64 is connected to one end of the resistor R56, the resistor R56 is connected to pin 1 of the transistor Q5, the pin 2 of the transistor Q5 is connected to the resistor R61 and then connected to the ground, the pin 3 of the transistor Q5 is connected to the resistor R52, the resistor R48 and one end of the capacitor C56 and then connected to VDD5, the other end of the resistor R52 is connected to pin 1 of the transistor Q5; one end of the capacitor C60 and the resistor R46 is connected to pin 6 of the operational amplifier U15B, the pins 5 and 8 of the operational amplifier U15B are connected to the resistor and capacitor, the pin 4 of the operational amplifier U15B is connected to the ground, and the pin 7 of the operational amplifier U15B is connected to one end of the resistor R46 and the capacitor C57;

[0062] Pin 2 of the operational amplifier U15A is connected to capacitor C58 and one end of resistor R44, the other end of resistor R44 is connected to one end of capacitor C54 and pin 1 of the operational amplifier U15A, pin 1 of the operational amplifier U15A is connected to one end of capacitor C62, the other end of capacitor C62 is sequentially connected to resistor R51, resistor R47, resistor R41, and pin 3 of comparator U14, pin 3 of the operational amplifier U15A is connected to R55, pin 4' of the operational amplifier U15A is connected to ground, and pin 8 of the operational amplifier U15B is connected to pin 8' of the operational amplifier U15A;

[0063] Pin 2 of the comparator U14 is connected to ground, pin 4 of the comparator U14 is connected to one end of resistors R54, R63 and R99, pin 5 of the comparator U14 is connected to VDD5, pin 1 of the comparator U14 is connected to one end of the resistor R40, and the other end LIDAR_START of the resistor R40 is connected to the STOP1 pin of TDC7201.

[0064] Specifically, operational amplifiers U15A and U15B are AD8052, and comparator U14 is TLV3601.

[0065] In one aspect of the present invention, the TDC timing circuit module is used for time measurement calculation of ultrasonic time difference.

[0066] The TDC7201 timing circuit module, such as Figure 6 As shown, it includes a timing chip U16, a resistor, and a capacitor. VREG1 of the timing chip U16 is connected to capacitor C67, VREG2 of the timing chip U16 is connected to capacitor C72, INTB1 of the timing chip U16 is connected to resistor R60, and the other end of resistor R60 is connected to VCC3.3, INTB2 of the timing chip U16 is connected to resistor R62, and the other end of resistor R62 is connected to VCC3.3, TRIGG1 and TRIGG2 of the timing chip U16 are connected to the STM32 microprocessor, and VDD1 and VDD2 of the timing chip U16 are connected to one end of capacitors C65 and C66 and then connected to VC C3.3 is connected, the ENABLE of the timing chip U16 is connected to the capacitor C70 and one end of the resistor R59, the other end of the resistor R59 is connected to VCC3.3, the CLOCK of the timing chip U16 is connected to the external 8M crystal oscillator, the SCLK, DIN, CSB1, CSB2, DOUT1, DOUT2 of the timing chip U16 are connected to the pins of the STM32 microprocessor, the START1 and START2 of the timing chip U16 are connected together and connected to the STM32 microprocessor, the STOP1 of the timing chip U16 is connected to the resistor R66 and then connected to the LIDAR START after the ultrasonic echo processing of the receiving circuit, the STOP2 of the timing chip U16 is connected to the resistor R65 and then connected to the LIDAR STOP after the ultrasonic echo processing of the receiving circuit.

[0067] Specifically, the timing chip U16 is TDC7201.

[0068] Ultrasonic flow rate measurement working process, such as Figure 7As shown in the figure, the STM32 microprocessor is initialized, TDC7201 is configured through SPI, the STM32 microprocessor controls the analog switch, switches the two ultrasonic transducers with opposite channels to the ultrasonic transmitting circuit, enables TDC7201, and the TDC timing circuit module sends a trigger pulse to the STM32 microprocessor. The STM32 microprocessor receives the trigger signal and sends a START pulse signal to the TDC7201 timing circuit module. At the same time, it sends a PWM signal through the ultrasonic transmitting circuit, that is, the amplifier circuit composed of a triode to drive the ultrasonic transducer. The STM32 microprocessor After the transducer sends the specified number of PWM signals, it controls the analog switch to open one of the channels, and the corresponding ultrasonic transducer receives the signal. The echo signal is processed by the second-order active filtering and amplification in the receiving circuit and then sent to TDC7201. TDC7201 calculates the ultrasonic transmission time of the downstream and upstream. TDC7201 sends an interrupt to the STM32 microprocessor. The STM32 microprocessor reads the data of the TDC timing circuit module through SPI, and calculates the ultrasonic transmission time difference of the downstream and upstream (the time difference is obtained by subtracting the downstream time from the upstream time) and the water flow rate and water flow. After measuring the water flow rate of all 16 channels, the STM32 microprocessor calculates the average flow rate and the total flow.

Claims

1. A multi-channel ultrasonic water velocity and flow measurement circuit, characterized in that: It includes a main control circuit module, a data storage circuit module, an ultrasonic transmission circuit module, an analog switch switching circuit module, an ultrasonic receiving circuit module, a TDC timing circuit module, and a 485 communication circuit module; wherein: the main control circuit module is electrically connected to the data storage circuit module, the analog switch switching circuit module, the TDC timing circuit module, and the 485 communication circuit module; the analog switch switching circuit module is electrically connected to the ultrasonic transmission circuit module and the ultrasonic receiving circuit module; the ultrasonic transmission circuit module is electrically connected to the ultrasonic transducer A and the ultrasonic transducer B, and the ultrasonic receiving circuit module is electrically connected to the ultrasonic transducer A and the ultrasonic transducer B; in: The main control circuit module is used to generate a 1MHz PWM signal, calculate the water flow rate and flow rate, and control other circuit modules to work together; The data storage circuit module is used to store data, including channel width, time difference, water flow speed and flow rate; The ultrasonic transmitting circuit module is used to boost the 1MHz PWM signal and drive the ultrasonic transducer A and the ultrasonic transducer B to transmit ultrasonic waves; The analog switch switching circuit module is used for switching the ultrasonic transducer A, the ultrasonic transducer B, the ultrasonic transmitting circuit module and the ultrasonic receiving circuit module; The ultrasonic receiving circuit module is used to receive the ultrasonic echo signal sent by the ultrasonic transmitting circuit module and perform second-order active filtering and amplification processing; The TDC timing circuit module is used for measuring and calculating the ultrasonic time difference; The 485 communication circuit module is used for exchanging data with the host computer and updating the program.

2. A multi-channel ultrasonic water velocity and flow measurement circuit according to claim 1, characterized in that: The main control circuit module specifically includes: The STM32 microprocessor and peripheral circuits are used to generate 1MHz PWM signals, calculate water flow rate and flow rate, and control other circuit modules to work together.

3. A multi-channel ultrasonic water flow velocity and flow measurement circuit according to claim 1, characterized in that: The ultrasonic transmitting circuit module is electrically connected to ultrasonic transducer A and ultrasonic transducer B through an analog switch switching circuit; the ultrasonic transmitting circuit module is an amplifier circuit composed of a triode, which is used to boost the 1MHzPWM signal and drive the 1MHz ultrasonic transducer A and ultrasonic transducer B to transmit ultrasonic waves.

4. A multi-channel ultrasonic water flow velocity and flow measurement circuit according to claim 1, characterized in that: The ultrasonic receiving circuit module has two paths, namely ultrasonic receiving circuit 1 and ultrasonic receiving circuit 2; the ultrasonic receiving circuit module includes: Operational amplifier, used for second-order active filtering and amplification processing of ultrasonic echo signals; Comparator, used for reprocessing the ultrasonic echo signal after passing through the operational amplifier.

5. A multi-channel ultrasonic water flow velocity and flow measurement circuit according to claim 1, characterized in that: The analog switch switching circuit module specifically includes: Control the enable signal and address selection signal line of the analog switch switching circuit module; Four analog switches, two of which are used to realize the switching of the ultrasonic transmitting circuit module to the ultrasonic transducer A and the ultrasonic transducer B, and the other two are used to realize the switching of the ultrasonic receiving circuit module to the ultrasonic transducer A and the ultrasonic transducer B; the ultrasonic transducer A and the ultrasonic transducer B are both ultrasonic transducers in the 16-way bidirectional transmitting and receiving channels.

6. A multi-channel ultrasonic water flow velocity and flow measurement circuit according to claim 1, characterized in that: The TDC timing circuit module specifically includes: TDC7201 and an external 8MHz clock are used to measure the ultrasonic transmission time in downstream and upstream water, with a measurement range of 12ns to 2000ns in mode 1, 250ns to 8ms in mode 2, and 0.25ns to 8ms in combined mode.

7. A multi-channel ultrasonic water flow velocity and flow measurement circuit according to claim 1, characterized in that: The 485 communication circuit module specifically includes: SP3485 and peripheral circuits are used to exchange data with the host computer and to update the program.

8. A multi-channel ultrasonic water velocity and flow measurement circuit according to claim 1, characterized in that: The following working steps are included; Step 1: Initialize the STM32 microprocessor of the main control circuit module and the TDC timing circuit module; Step 2: The STM32 microprocessor controls the analog switch to switch the channels relative to the two ultrasonic transducers A and B to the ultrasonic transmitting circuit module; Step 3: The TDC timing circuit module sends a trigger signal to the STM32 microprocessor of the main control circuit module; Step 4: The STM32 microprocessor of the main control circuit module receives the trigger signal, sends a PWM signal to drive ultrasonic transducer A and ultrasonic transducer B at the same time, and sends a RE_START signal to the TDC timing circuit module, and the TDC timing circuit module starts working and timing; Step 5: After the STM32 microprocessor of the main control circuit module sends the specified number of PWM signals, it controls the analog switch to switch the measurement channel relative to the two ultrasonic transducers A and B to the ultrasonic receiving circuit module; Step 6: After receiving the signal, the echo circuits of the two-way ultrasonic transducer A and the ultrasonic transducer B simultaneously send the signal to the TDC timing circuit module, and the TDC timing circuit module calculates the ultrasonic transmission time of the downstream and upstream; Step 7: The TDC timing circuit module sends an interrupt to the STM32 microprocessor of the main control circuit module. The main control circuit module reads the data of the TDC timing circuit module through SPI, and calculates the time difference of ultrasonic transmission in the downstream and upstream directions and the water flow rate; Step 8: Return to step 2 and measure the next channel; Step 9: After measuring the water flow rates of all 16 channels, the STM32 microprocessor of the main control circuit module calculates the average flow rate and total flow rate; Step 10: Return to step 1 and measure again.

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