A measurement module for an average velocity tube vortex street integrated sensor

Abstract

The present invention provides a measurement module of an integrated sensor of an average velocity tube vortex street, comprising a power supply unit module, a step-down circuit module, a linear voltage stabilizing circuit module, a first chip, a second chip, a third chip, a Bluetooth communication unit module and an interface circuit module: the output end of the power supply unit module is connected to the input end of the step-down circuit module, the output end of the step-down circuit module is connected to the input end of the linear voltage stabilizing circuit module, the output end of the linear voltage stabilizing circuit module is connected to the input end of the first chip, the second chip, the third chip and the Bluetooth communication unit module; the signal output end of the first chip is connected to the signal input end of the second chip; the second chip is electrically connected to the Bluetooth communication unit module; the output end of the second chip is connected to the input end of the third chip. The present invention reduces the overall power consumption of the system and finally achieves a current output of 4 to 20 mA.

Description

Technical Field

[0001] The invention belongs to the technical field of two-phase flow detection, and in particular relates to a measurement module of an average velocity tube vortex street integrated sensor. Background Art

[0002] At present, there are many kinds of flow rate instruments used in industrial production. According to the difference in measurement method and structure, they can be divided into eleven categories, including differential pressure flowmeter, volumetric flowmeter, fluid vibration flowmeter, ultrasonic flowmeter, insertion flowmeter, open channel flowmeter and other flowmeters.

[0003] Vortex flowmeter is a liquid vibration flowmeter. Under a certain water flow environment, part of the liquid will be converted into liquid vibration, and the frequency of the vibration will change with the change of water flow velocity (flow rate). The flowmeter working according to this law is called a liquid vibration flowmeter. In 1878, Strauha first proposed the relationship between the oscillation frequency and speed of the liquid, and used the Strauha number to describe the relationship between the speed and diameter of the vortex and the speed. In the past, the research on the vortex phenomenon focused on disaster prevention. For example, in boilers and heat exchangers, when the self-vibration of the pipeline matches the vortex vibration frequency, resonance will occur, causing damage to the device. In the 1950s, people conducted a large number of experiments on wind meters, ship speed meters, etc. The development of vortex flowmeters began in the late 1960s, among which hot wire detection method and thermal detection method vortex flowmeters came out one after another. Vortex flow measurement technology has developed rapidly in the 1970s and 1980s, and a variety of vortex flow measurement technologies such as stress measurement technology, capacitance measurement technology, ultrasonic measurement technology, vibration measurement technology, strain measurement technology, photoelectric measurement technology, and fiber measurement technology have emerged. After the 1990s, vortex flowmeters with various measurement methods such as differential pressure and ultrasonic have been introduced one after another. In recent years, with the continuous development of new technologies, vortex flowmeters have also made certain progress in integration, multi-parameter detection, and intelligence. Among the many measurement modes, the pressure type (also known as piezoelectric) vortex flowmeter is considered to be the mainstream of the current vortex flowmeter because of its fast response speed, high signal strength, wide operating temperature range, good field adaptability and high reliability. In the stress vortex flowmeter, the sensor transmits the lift force borne by the sensor to the sensor in the form of pressure, and converts it into AC charge, and then obtains the eddy current signal through charge amplification, filtering and shaping. Piezoelectric sensors have fast response speed, strong signal, good machinability and low manufacturing cost, but their disadvantage is that they are more sensitive to vibration.

[0004] Tinh and Evangelisti et al. found in their previous studies that the working environment and the fluctuation of the liquid itself will significantly change the measurement results of the vortex signal. The two main defects in vortex measurement: poor anti-noise performance and insensitivity to low speed, etc., are important ways to solve these two defects. Cousins ​​confirmed through many experimental studies that the role of the inner wall of the tube on the Karman vortex street should not be underestimated, and proposed several different types of inner wall surfaces and the optimal interception rate of the inner wall of the tube, among which the optimal interception rate for the cylindrical shape is between 0.33-0.38; the shape of the equilateral triangle is 0.29-0.32; the size of the cube is 0.24-0.28. Igarashi and Keefe first proposed a new design concept of vortex generator and conducted a theoretical analysis on it. Bentley and Benson et al. used different types of cylinders to form a vortex generator. The results showed that when two or three cylinders are combined to form a vortex generator, the vortex generator has better rotation strength and better stability than a single cylinder. In 2003, Bentley and Mudd et al. used high-speed photography to conduct experimental research on the vortex shedding mechanism of square cylinders and square cylinder-triangular cylinder mixtures. Fuxin and Jiangang P et al. selected the best vortex generator composed of double triangular cylinders by combining two triangular prisms.

[0005] Berlinski et al. used a hot wire anemometer to study the flow field in the vortex flowmeter by calculating the average flow velocity. Terao et al. used a hot wire anemometer to confirm that the vortex formed by a cylindrical fluid in a tube is larger than the vortex formed in a free flow field, and is greatly affected by the inner wall of the tube. The stability of the vortex in the tube is also less than that in the free flow field, but its mechanism is still unclear. This project will further study the mechanism of vortex formation in a tube by a cylindrical fluid. Based on the theory that the vortex can control ultrasonic signals, Hans and Menz proposed a vortex frequency detection method based on ultrasonic detection technology. This method can obtain a very small detection range, but its detection range is significantly affected by factors such as bubbles, solid particles and temperature. In the vortex flowmeter, the vortex flowmeter produced by Kent Company first used the capacitance method. Capacitive detection usually uses differential lines and has good shockproof effect, but its disadvantage is that it is not suitable for the detection of dirty and corrosive liquids. Fischer & Porter and Foxboro used piezoelectric elements to detect the frequency of the vortex in the early days. In recent years, Eastech et al. proposed placing a small nickel ball in a vortex generator. When a vortex is generated on the vortex generator, the small nickel ball will oscillate, thereby realizing the detection of the frequency of the vortex generation.

[0006] Schlatter et al. analyzed the noise of the vortex flowmeter under working conditions, and based on the excitation noise mode and signal mode, used frequency conversion and correlation power spectrum method to reduce the noise. Kawano proposed a high-precision measurement technology based on vortex street, adopted a high-precision measurement technology based on single-chip microcomputer, and adopted a new function-based discriminator to further improve the stability of the measurement system. Using Amadi-E technology, for three typical working conditions of on-site centrifugal pumps, volumetric pumps and vibrators, the frequency domain characteristics of the FFT frequency band were used. Through the analysis of the frequency domain characteristics, the vortex flow data of Tianjin University was effectively extracted, thereby achieving the purpose of improving the accuracy of vortex flow data collection. Menz introduced multiple multi-source information fusion technologies into flow detection and developed an ultrasonic vortex flowmeter, which can not only detect the frequency of vortex separation, but also detect the interval between two measured points to obtain the flow. By fusing the two sets of data, new data is obtained, which greatly improves the accuracy of the test. Masanori Hondoh et al. combined traditional circuit analysis, filtering technology,

[0007] In practical applications, there are still many problems with vortex flowmeters, the most prominent of which are the unmeasurability of the signal when the vortex signal is at a low signal-to-noise ratio within the entire measuring range, and the inability to directly measure the mass flow of the vortex flowmeter, especially the steam mass flow. With the rapid development and widespread application of digital signal processing technology, complex signal processing algorithms have been implemented in hardware.

[0008] Steam, especially saturated steam, is widely used in industry as an important secondary energy source. Vortex flowmeter is widely used in steam measurement due to its unique characteristics that the frequency of vortex generator is only related to the flow velocity of the measured fluid, and is almost unaffected by changes in fluid properties (temperature, pressure, viscosity, density, etc.) within a certain Reynolds number range. It has small pressure loss, is beneficial to energy saving, and has high measurement accuracy.

[0009] In view of the problem that the steam mass flow cannot be directly measured, the industrial site generally uses the table lookup method and formula calculation method to calculate the steam density. Although the table lookup method can obtain high compensation accuracy, its disadvantages are also prominent. First of all, the input data volume is huge, which requires a lot of storage space; secondly, the application of the data table must first determine whether it is saturated steam or superheated steam, and then look up different data tables; in addition, the variables in the data table are non-continuous quantities with certain compensation. For the data between two points, it is necessary to obtain it through mathematical interpolation, and the interpolation formula of the binary function is not simple. Formula calculation method The superheated steam density calculation formulas commonly used in current engineering mainly include experimental fitting formulas and Ukanovich formulas. For occasions where the working conditions vary widely or the accuracy requirements are high, the flow compensation using the above formula for water vapor density compensation has a large deviation, and it is necessary to first determine whether it is saturated steam or superheated steam under the working conditions before choosing different calculation formulas for calculation, which also brings certain limitations to the on-site application. Summary of the invention

[0010] The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a measurement module of an average-speed tube vortex integrated sensor. In order to reduce the overall power consumption of the system, a low-power STM32F103C8T6 single-chip microcomputer is selected, and a variety of methods and measures for reducing power consumption are adopted, and a large amount of debugging and experimental work is done to reduce the overall power consumption of the system, and finally achieve a current output of 4 to 20 mA. The circuit board is connected to the vortex flowmeter to collect differential pressure signals, temperature signals, frequency signals and pressure signals, and the single-chip microcomputer controls the circuit board to process data, and is connected to the host computer, which can be displayed in real time on the computer.

[0011] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A measurement module of an average velocity tube vortex street integrated sensor includes a power supply unit module, a step-down circuit module, a linear voltage stabilization circuit module, a first chip, a second chip, a third chip, a Bluetooth communication unit module and an interface circuit module:

[0013] The output end of the power supply unit module is connected to the input end of the step-down circuit module, the output end of the step-down circuit module is connected to the input end of the linear voltage regulator circuit module, and the output end of the linear voltage regulator circuit module is connected to the input end of the first chip, the second chip, the third chip and the Bluetooth communication unit module to supply power to the first chip, the second chip, the third chip and the Bluetooth communication unit module.

[0014] The signal output end of the first chip is connected to the signal input end of the second chip, and the external sensor signal is connected to the first chip through the P3 connector to isolate and protect the voltage signal, and then transmitted to the second chip through the contact;

[0015] The second chip is electrically connected to the Bluetooth communication unit module to establish a remote communication connection with the host computer through the Bluetooth communication unit module;

[0016] The output end of the second chip is connected to the input end of the third chip, and the third chip is connected to an external device through the interface circuit module.

[0017] Furthermore, it also includes an operational amplifier, which is configured at the input end of the first chip, the second chip and / or the third chip, and the operational amplifier is connected to a power supply.

[0018] Furthermore, the power supply is a single power supply of 3.0V to 36V or a dual power supply of ±1.5V to ±18V.

[0019] Furthermore, the power supply unit module includes a P1 serial port for inputting voltage, a diode for preventing reverse flow, and a capacitor for filtering.

[0020] Furthermore, the step-down circuit module is a DC-DC step-down circuit, which is used to reduce the voltage provided by the power supply unit module to 5V.

[0021] Furthermore, the linear voltage stabilizing circuit module is a buck chip, which reduces the voltage output by the buck circuit module to 3.3V.

[0022] Furthermore, the second chip is a STM32F103C8T6 single chip microcomputer.

[0023] Furthermore, the third chip is connected to an external device through the interface circuit module and then through the P2 connector.

[0024] Furthermore, it also includes a burning port unit, and the second chip outputs data to the display screen through the burning port unit.

[0025] Furthermore, the interface circuit module is a 485 interface circuit module.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) Based on the current status of digital vortex flowmeter research at home and abroad, the present invention has developed an integrated measurement module for averaging tube vortex flowmeters to solve the problem that steam mass flow cannot be directly measured. The present invention uses a low-power STM32F103C8T6 single-chip microcomputer, adopts a variety of methods and measures to reduce power consumption, does a lot of debugging and experimental work, reduces the overall power consumption of the system, and finally achieves a current output of 4-20mA.

[0028] 2) The present invention realizes the function of remote connection to the host computer through the Bluetooth module to avoid the danger brought by steam to the operator. It is a mature average-velocity tube vortex street integrated measurement module with high measurement accuracy, low system power consumption, fast response speed, wide measurement medium, various complete functions, good reliability and intrinsic safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the description of the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0030] Figure 1 A schematic structural diagram of a measurement module of an average velocity tube vortex street integrated sensor provided in an embodiment of the present invention.

[0031] Figure 2 A circuit block diagram of a measurement module of an average velocity tube vortex street integrated sensor provided in an embodiment of the present invention.

[0032] Figure 3 The present invention provides a control flow chart of the host computer.

[0033] Figure 4 This is a schematic diagram of the DC24V power supply design provided in an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of the design principle of a DC-DC step-down circuit provided in an embodiment of the present invention.

[0035] Figure 6 This is a schematic diagram of a linear voltage stabilization circuit design provided by an embodiment of the present invention.

[0036] Figure 7 This is a schematic diagram of the design of a control unit provided in an embodiment of the present invention.

[0037] Figure 8 This is a schematic diagram of the design principle of the Bluetooth communication unit provided in an embodiment of the present invention.

[0038] Fig. 9 This is a schematic diagram of the 485 interface circuit design provided by an embodiment of the present invention.

[0039] Fig.10 This is a schematic diagram of the design principle of the programming port unit provided in an embodiment of the present invention.

[0040] Fig.11 This is a schematic diagram of the operational amplifier design provided by an embodiment of the present invention.

[0041] In the figure, 1 is a power supply unit module, 2 is a step-down circuit module, 3 is a linear voltage regulator circuit module, 4 is a first chip, 5 is a second chip, 6 is a third chip, 7 is a Bluetooth communication unit module, 8 is an interface circuit module, 9 is a P3 connector, 10 is a host computer, and 11 is an external device. DETAILED DESCRIPTION

[0042] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] like Figure 1 As shown, an embodiment of the present invention provides a measurement module of an average velocity tube vortex street integrated sensor, including a power supply unit module 1, a step-down circuit module 2, a linear voltage regulator circuit module 3, a first chip 4, a second chip 5, a third chip 6, a Bluetooth communication unit module 7 and an interface circuit module 8:

[0045] The output end of the power supply unit module 1 is connected to the input end of the step-down circuit module 2, the output end of the step-down circuit module 2 is connected to the input end of the linear voltage regulator circuit module 3, and the output end of the linear voltage regulator circuit module 3 is connected to the input end of the first chip 4, the second chip 5, the third chip 6 and the Bluetooth communication unit module 7 to supply power to the first chip 4, the second chip 5, the third chip 6 and the Bluetooth communication unit module 7.

[0046] The signal output end of the first chip 4 is connected to the signal input end of the second chip 5, and the external sensor signal is connected to the first chip 4 through the P3 connector 9 to isolate and protect the voltage signal, and then transmitted to the second chip 5 through the contact;

[0047] The second chip 5 is electrically connected to the Bluetooth communication unit module 7 to establish a remote communication connection with the host computer 10 through the Bluetooth communication unit module 7;

[0048] The output end of the second chip 5 is connected to the input end of the third chip 6 , and the third chip 6 is connected to the external device 11 through the interface circuit module 8 .

[0049] In this embodiment, the first chip 4 is selected as a KKU1 chip, the second chip 5 is a U4 single-chip microcomputer, the third chip 6 is a U1 single-chip microcomputer, the interface circuit module 8 is a 485 interface circuit, and the buck circuit module is a DC-DC buck circuit module. Its working principle is as follows:

[0050] The power supply unit module uses a DC24V power supply, which is reduced to 5V through the DC-DC step-down circuit module, and then reduced to 3.3V through the linear regulator module, and finally provides power for the U4 microcontroller, KKUI chip, U1 chip and Bluetooth module; the external sensor signal is connected to the KKU1 chip via the P3 connector, isolated and protected, and then transmitted to the U4 microcontroller via the 100KPA contact. The U4 microcontroller can be connected to the Bluetooth module via the USART2 serial port to achieve remote connection to the host computer. In the USART1 serial port, the program can be burned and the external display can be operated. The USART3 serial port can also be used to connect to the U1 chip to convert the USART level output by the microcontroller into a 485 level, and then output it to the external device through the P2 connector.

[0051] The U4 MCU is the core processing unit of the system, which communicates with other devices through different serial ports. Through the USART2 serial port, the U4 MCU can be connected to the Bluetooth module to achieve remote communication so as to exchange data with the host computer. At the same time, the U4 MCU can also burn programs through the USART1 serial port and connect to an external display to display system status or data. In addition, the U4 MCU is also connected to the U1 chip through the USART3 serial port. The U1 chip converts the USART signal output by the MCU into 485 level, and then these signals are output to external devices through the P2 interface.

[0052] In some embodiments, the second chip uses a Cortex-M3 chip as a controller, and its chip model is: STM32F103C8T6, and its highest main frequency is 72MHz. It is a 32-bit high-performance processor that can meet the needs of controlling the circuit board and collecting and processing signals.

[0053] In some embodiments, the Bluetooth communication unit uses RF-BM-BG22A3L as a communication controller. This module has an independent isolation function and a master-slave working mode, and can be widely used in short-range wireless communications. It has the advantages of low power consumption, small size, long distance, and high anti-interference. The USART2 serial port connects U4 to the Bluetooth chip, and the host computer uses the Bluetooth chip to connect to U4. The Bluetooth communication system communicates with the host computer, accepts commands from the host computer, and transmits sensor data to the host computer.

[0054] In some embodiments, the 485 interface circuit uses the RS485 interface chip: SP3485EN-L / TR, with a typical single power supply voltage of 3.3 V. The function of the U1 chip is to convert the TTL level of the USART3 serial port of the microcontroller into the 485 level through the U1 chip, so as to make the transmission distance longer.

[0055] In some embodiments, the device further comprises an operational amplifier, which is a dual-channel, precision 16MHz, JFET input operational amplifier with isolation and protection microcontroller functions, which can use a single power supply of 3.0V to 36V or a dual power supply of ±1.5V to ±18V. The system has the function of a single power supply, and in the case of a single power supply, its output voltage can reach an output below the ground voltage.

[0056] In a specific embodiment, Figure 2 As shown in the figure, it is a circuit block diagram of the measurement module of the integrated sensor of the averaging tube vortex street. When the module is working, the external 24V power supply is stepped down and filtered to 5V by U15, and then stepped down and filtered to 3.3V by U17 to power the U4 microcontroller, KKUI chip, U1 chip and Bluetooth module; the external sensor signal is connected to the KKU1 chip through the P3 connector to isolate and protect the voltage signal, and then transmitted to the U4 microcontroller through the 100KPA contact. The U4 microcontroller can be connected to the Bluetooth module through the USART2 serial port for remote connection to the host computer, program burning and external display screen are performed through the USART1 serial port, and the U1 chip is connected through the USART3 serial port. The USART level output by the microcontroller is converted to 485 level and then output to the external device through the P2 connector.

[0057] When the measurement module of the averaging tube vortex street integrated sensor is connected to a host computer, the control flow of the host computer is as follows: Figure 3 As shown, the specific implementation steps are as follows:

[0058] First start the host computer program, then enter the user name and password. If it is wrong, return to the previous step. If it is correct, go to the next step to select the serial port, click to open the serial port, then set the fluid type, sensor diameter, pressure, temperature and instrument coefficient, then click to confirm. After clicking the start button, the real-time instantaneous flow, frequency and pressure difference are displayed in the middle of the screen. Click to save and finally stop working.

[0059] Figure 4 The power supply part shown uses DC24V, which is input from the P1 serial port. The diode D4 is used for reverse protection, and the capacitor C1 is used for filtering to make the voltage more stable.

[0060] Figure 5 In the DC-DC step-down circuit shown, the LM2596SX-5.0 / NOPB step-down chip is selected because the driving voltage requirement of the vortex flowmeter is relatively low. The 24V voltage is converted to 5V after U15 as a DC-DC step-down power supply.

[0061] Figure 6 The circuit shown is a linear stabilization circuit. Because the power supply of the vortex flowmeter requires low voltage, the AMS1117-3.3 step-down chip is selected, and the 5V voltage is converted to 3.3V through U17.

[0062] Figure 7 It is a control unit module, which is mainly composed of a controller and an acquisition circuit. It uses a Cortex-M3 chip as the controller, the chip model is STM32F103C8T6, the highest main frequency is 72MHz, and the chip is a 32-bit high-performance processor, which can meet the needs of controlling circuit boards, collecting signals and processing data.

[0063] Figure 8 It is a Bluetooth communication unit module, using RF-BM-BG22A3L as the communication controller. The module has its own isolation function and master-slave mode, which can be widely used in the field of short-distance wireless communication. It has the characteristics of low power consumption, small size, long transmission distance, and strong anti-interference ability. The USART2 serial port connects U4 and Bluetooth chip, and the host computer connects to U4 microcontroller via Bluetooth. The Bluetooth module exchanges information with the host computer, receives host computer commands, and sends sensor information to the host computer.

[0064] Fig. 9 The figure shows a 485 interface circuit module using the RS485 interface chip SP3485EN-L / TR, whose typical single power supply voltage is 3.3 V. The function of U1 is to convert the TTL level of the USART3 serial port to the 485 level, thereby achieving the purpose of extending the data transmission distance.

[0065] Fig.10It is a programming port unit module. The serial port 1 of the microcontroller outputs data to the LED screen through the 5678 terminal.

[0066] Fig.11 AD823ARZ-R7 is an operational amplifier module, dual-channel, high-precision, 16MHz, JFET input operational amplifier, with isolation and protection functions, can use a single power supply of 3.0V to 36V, or a dual power supply of ±1.5V to ±18V. It adopts a single-machine power supply mode, and when working alone, the input voltage range can be expanded to below the ground voltage.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A measurement module of an average velocity tube vortex street integrated sensor, characterized in that: It includes a power supply unit module, a step-down circuit module, a linear voltage regulator circuit module, a first chip, a second chip, a third chip, a Bluetooth communication unit module and an interface circuit module: The output end of the power supply unit module is connected to the input end of the step-down circuit module, the output end of the step-down circuit module is connected to the input end of the linear voltage regulator circuit module, and the output end of the linear voltage regulator circuit module is connected to the input end of the first chip, the second chip, the third chip and the Bluetooth communication unit module to supply power to the first chip, the second chip, the third chip and the Bluetooth communication unit module. The signal output end of the first chip is connected to the signal input end of the second chip, and the external sensor signal is connected to the first chip through the P3 connector to isolate and protect the voltage signal, and then transmitted to the second chip through the contact; The second chip is electrically connected to the Bluetooth communication unit module to establish a remote communication connection with the host computer through the Bluetooth communication unit module; The output end of the second chip is connected to the input end of the third chip, and the third chip is connected to an external device through the interface circuit module; It also includes an operational amplifier, which is configured at the input end of the first chip, the second chip and / or the third chip, and is connected to a power supply; The second chip is a STM32F103C8T6 single chip microcomputer; The third chip is connected to an external device through the interface circuit module and then through the P2 connector; It also includes a burning port unit, and the second chip outputs data to the display screen through the burning port unit.

2. The measurement module of the average velocity tube vortex street integrated sensor according to claim 1, characterized in that: The power supply is a single power supply of 3.0V to 36V or a dual power supply of ±1.5V to ±18V.

3. The measurement module of the average velocity tube vortex street integrated sensor according to claim 1, characterized in that: The power supply unit module includes a P1 serial port for inputting voltage, a diode for preventing reverse flow, and a capacitor for filtering.

4. The measurement module of the average velocity tube vortex street integrated sensor according to claim 1, characterized in that: The step-down circuit module is a DC-DC step-down circuit, which is used to reduce the voltage provided by the power supply unit module to 5V.

5. The measurement module of the average velocity tube vortex street integrated sensor according to claim 1, characterized in that: The linear voltage stabilizing circuit module is a step-down chip, which reduces the voltage output by the step-down circuit module to 3.3V.

6. The measurement module of the average velocity tube vortex street integrated sensor according to claim 1, characterized in that: The interface circuit module is a 485 interface circuit module.

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