Automatic batch calibration pressure sensor circuit

Abstract

The utility model discloses a circuit for automatically calibrating pressure sensors in batches. The circuit comprises an MCU main control circuit, a data acquisition circuit and a plurality of output selection circuits. The MCU main control circuit is used for executing a program instruction stored in the memory, processing an input signal and controlling external equipment through an output signal; the data acquisition circuit is electrically connected with the MCU main control circuit, converts an analog signal into a digital signal, acquires and processes the digital signal, and transmits the digital signal to the MCU main control circuit; the input ends of the multiple output selection circuits are electrically connected with the MCU main control circuit, the output ends of the multiple output selection circuits are connected with the sensors, and the MCU main control circuit controls output lines of the multiple output selection circuits so as to calibrate the pressure sensors. The circuit for automatically calibrating the pressure sensors in batches can calibrate the sensors in high precision, eliminates personal errors through digital control, improves calibration precision, and is high in batch calibration efficiency.

Description

Technical Field

[0001] This utility model relates to the field of calibration circuit technology, specifically to an automatic batch calibration circuit for pressure sensors. Background Technology

[0002] Because pressure sensors are sensitive components with highly variable electrical parameters, and are also temperature-sensitive, sensor manufacturers must calibrate them. Currently, sensor calibration is performed using hardware. Operators use laser cutting equipment to cut the thick-film resistor on the sensor, adjusting its resistance value to achieve the calibration purpose.

[0003] like Figure 1 As shown, Figure 1 This is a circuit component layout diagram of a sensor in the prior art. Figure 1 In this circuit, resistors R1, R2, R3, and R4 are thick-film resistors, and their resistance values ​​are adjusted by laser cutting the surface of the resistors.

[0004] The solution that uses hardware to calibrate the sensor has the following problems:

[0005] 1. Low sensor accuracy. Due to large errors in manual operation, it is impossible to obtain accurate resistance values, resulting in inaccurate calibration.

[0006] 2. External factors such as moisture, dust, or oxidation can cause changes in the original resistance, leading to calibration failure.

[0007] 3. High operator requirements. Because laser cutting is a precision cutting process performed under a microscope, it requires a very high level of operator proficiency and must undergo extensive professional training before being allowed to work.

[0008] 4. Low efficiency.

[0009] 5. Low yield. Utility Model Content

[0010] To address the shortcomings of existing technologies, the present invention aims to provide an automatic batch calibration circuit for pressure sensors.

[0011] To solve the above technical problems, this utility model provides the following solution: An automatic batch calibration pressure sensor circuit of this utility model includes:

[0012] The MCU main control circuit is used to execute program instructions stored in memory, process input signals, and control external devices through output signals;

[0013] The data acquisition circuit is electrically connected to the MCU main control circuit. The data acquisition circuit converts analog signals into digital signals, acquires and processes them, and then transmits them to the MCU main control circuit.

[0014] The circuit has multiple output selection circuits. The input terminal is electrically connected to the MCU main control circuit, and the output terminal is connected to each sensor. The output line of the multiple output selection circuit is controlled by the MCU main control circuit to calibrate the pressure sensor.

[0015] Furthermore, the MCU main control circuit includes an MCU, which has a multi-channel selection output circuit;

[0016] The MCU is connected to a storage chip U24, a crystal oscillator circuit, a reset connector, a filter circuit, and an integrated isolated data transceiver circuit.

[0017] Furthermore, the MCU selected is the MC9S08A260.

[0018] Furthermore, the integrated isolated data transceiver circuit uses an RS-485 signal transmission circuit.

[0019] Furthermore, the data acquisition circuit includes:

[0020] A signal conversion circuit connected to the MCU and used to convert analog signals into digital signals;

[0021] The power supply circuit has a first step-down circuit and a second step-down circuit connected to the output terminal of the first step-down circuit. The second step-down circuit outputs a reference voltage, which is supplied to the signal conversion circuit.

[0022] A voltage and current measurement circuit is connected to the output terminal of the signal conversion circuit to detect the voltage and current in the signal conversion circuit.

[0023] The analog-to-digital converter circuit has its input terminal connected to the MCU, which is used to communicate with external devices. It receives the voltage and current signals conditioned by the front end and converts them into digital signals for output.

[0024] The voltage reference circuit is electrically connected to the MCU to provide a stable reference level for the system and ensure the accuracy of the measurement.

[0025] Furthermore, the multiple output selection circuit includes:

[0026] Connector J2 has multiple input / output ports and is connected to the MCU;

[0027] The communication interface chip U13, which is connected to the MCU, is used for RS-485 communication;

[0028] The multi-channel optocoupler circuit connected to the connector J2;

[0029] A relay circuit connected to the communication interface chip U13, which is connected to a multi-channel optocoupler circuit, is used to control the switching of the multi-channel optocoupler circuit.

[0030] A switching circuit connected to the MCU, which is also connected to the relay circuit.

[0031] Furthermore, the switching circuit includes a voltage regulator circuit, a current detection and amplification circuit connected to the voltage regulator circuit, and a single-channel inverting circuit.

[0032] Compared with the prior art, the beneficial effects of this utility model are:

[0033] 1. The automatic batch calibration pressure sensor circuit of this utility model can calibrate the sensor with high precision, and digital control eliminates human error, improves calibration accuracy, and has high batch calibration efficiency.

[0034] 2. The automatic batch calibration circuit of this utility model has strong batch processing capability, avoids interference from environmental factors, and has stable calibration capability.

[0035] 3. The automatic batch calibration circuit of this utility model reduces manual intervention and lowers labor costs.

[0036] 4. The automatic batch calibration pressure sensor circuit of this utility model supports remote control and data recording. Attached Figure Description

[0037] Figure 1 This is a circuit element layout diagram of a sensor in the existing technology.

[0038] Figure 2 This is a block diagram of the MCU control principle of this utility model.

[0039] Figure 3 These are the four directional indicator codes for the MCU of this utility model.

[0040] Figure 4 for Figure 3 Circuit diagram for area A.

[0041] Figure 5 for Figure 3 Circuit diagram of area B.

[0042] Figure 6 for Figure 3 The circuit diagram for area C.

[0043] Figure 7 for Figure 3 The circuit diagram for area D.

[0044] Figure 8-9 This is the peripheral circuit diagram of the MCU of this utility model.

[0045] Figure 10-12 This is the data acquisition circuit diagram of this utility model.

[0046] Figure 13-18 This is a circuit diagram showing the multiple output selection options for this utility model. Detailed Implementation

[0047] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments, so that the advantages and features of the present utility model can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present utility model. Obviously, the embodiments described in this utility model are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0048] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0049] Example 1: The specific structure of this utility model is as follows:

[0050] Please refer to the appendix. Figure 2-18 This utility model discloses an automatic batch calibration pressure sensor circuit, which includes an MCU main control circuit, a data acquisition circuit, and multiple output selection circuits.

[0051] like Figure 2-9 As shown, the MCU main control circuit is used to execute program instructions stored in the memory, process input signals, and control external devices through output signals. The MCU main control circuit includes an MCU with a multi-channel selectable output circuit; the MCU is connected to a memory chip U24, a crystal oscillator circuit, a reset connector, a filter circuit, and an integrated isolated data transceiver circuit. Preferably, the MCU model is MC9S08A260. The integrated isolated data transceiver circuit uses an RS-485 signal transmission circuit.

[0052] like Figure 8 As shown, Figure 8 It is a commonly used serial electrically erasable programmable read-only memory U24. The read-only memory U24 is connected to the MCU for storing a small amount of data. The model of the read-only memory U24 is 24LC128. Its 8th pin is connected to VCC_5V voltage, its 6th pin is connected to the SCL_5V pin of the MCU, and its 5th pin is connected to the SDA_5V pin of the MCU.

[0053] like Figure 9 As shown, Figure 9 This is the peripheral circuit diagram of the MCU of this utility model. Figure 9 The top left corner contains a crystal oscillator circuit, which provides the clock signal to the system. Capacitors are used for frequency fine-tuning and stabilizing oscillation, while resistors assist in starting the oscillation. This crystal oscillator circuit is connected to the MCU's EXTAL pin and XTAL pin (area A).

[0054] Figure 9 Chip U25 is used for RS-485 communication. Its pin functions are as follows: VCC connects to a 5V power supply, GND is grounded; RxD1 and TxD1 are the receive and transmit data pins, respectively; PTE2 controls receive enable, and Tx1 controls transmit enable; A and B are RS-485 differential signal pins used for long-distance, high-speed communication; GND485 is the isolation ground, and VISOOUT is the isolation power output. Chip U25's RxD1 is connected to the MCU's RxD1 pin, and chip U25's TxD1 is connected to the MCU's TxD1 pin.

[0055] Figure 9 It also includes a power filtering circuit, an electrostatic discharge (ESD) protection circuit, and an RS-485 signal interface circuit. The filtering circuit comprises an RC filter circuit and a circuit consisting of multiple capacitors connected in parallel. In the RC filter circuit, one end of resistor R2312 is connected to VCC_5V, and the other end is connected to two capacitors connected in parallel, with the other ends of the two capacitors grounded. The filter circuit consisting of multiple capacitors connected in parallel is connected to VCC_5V, with the other end grounded. The ESD protection circuit includes a PESD15VL2BT ESD protection diode U26, which protects the PS-485 interface from transient voltage surges such as electrostatic discharge, preventing damage to the interface circuitry. The electrostatic discharge (ESD) protection circuit is connected to a voltage divider circuit consisting of multiple resistors, including resistors R251, R255, R252, R253, and R254. Resistors R251, R255, and R252 are connected in series, with one end connected to the VISOOUT circuit and the other end grounded. The circuit node between resistors R251 and R255 is connected to resistors R253 and the 485_A circuit, respectively. The other end of resistor R253 is connected to pin A of chip U25. The circuit node between resistors R255 and R252 is connected to resistors R254 and the 485_B circuit, respectively. The other end of resistor R254 is connected to pin B of chip U25. Circuits 485_A and 485_B are connected to pins 2 and 1 of the ESD protection diode U26, respectively.

[0056] Figure 10-12This is a circuit diagram of the data acquisition circuit of this utility model. The data acquisition circuit is electrically connected to the MCU main control circuit. This data acquisition circuit converts analog signals into digital signals, acquires and processes them, and then transmits them to the MCU main control circuit.

[0057] The data acquisition circuit includes:

[0058] The signal conversion circuit connected to the MCU and used for converting analog signals into digital signals ( Figure 10 Upper circuit);

[0059] The power supply circuit includes a first step-down circuit and a second step-down circuit connected to the output terminal of the first step-down circuit. The second step-down circuit outputs a reference voltage, which is supplied to the signal conversion circuit. Figure 10 (Lower circuit)

[0060] A voltage and current measurement circuit, connected to the output terminal of the signal conversion circuit, detects the voltage and current in the signal conversion circuit. Figure 11 );

[0061] The analog-to-digital converter circuit, with its input terminal connected to the MCU, is used for communication with external devices. It receives voltage and current signals conditioned by the front end and converts them into digital signals for output. Figure 12 );

[0062] Voltage reference circuit ( Figure 12 It is electrically connected to the MCU to provide a stable reference level for the system and ensure the accuracy of the measurement.

[0063] Specifically, such as Figure 10 As shown, in the signal conversion circuit, the OWI_TX_MCU of U27 (P82B96DR) is connected to the Sx pin of the chip and pulled up to VCC_5V through R271 (4.7KΩ, NC indicates not connected); R273 (0 resistance, 0603_RES package) is connected to the Rx pin, and the Tx pin is also connected to ground. This configuration is commonly used in one-wire communication circuits to connect devices such as sensors for data transmission.

[0064] U28 (AD719): This is an analog correlation chip. VCC_5V powers the chip after being filtered by C281 (100nF). Aout / OWI_sel is used to select signal output or single-bus communication. The AIN+ pin is used to receive analog input signals, and sensor_VOUT_0-5V represents the 0-5V analog voltage signal output by the sensor. This chip is used to process or convert analog signals.

[0065] Figure 10In the lower circuit, U29 (LM1117 - ADJ) is a low-dropout linear regulator. The input is VCC_7V, which is filtered by C291 (10μF / 25V) and then connected to the IN pin. The ADJ pin uses a voltage divider network of R291 (1kΩ) and R292 (3.09KΩ) to adjust the output voltage to VCC_5.3V. C292 (22μF / 25V) is used for further filtering.

[0066] U30 (ADR4550): is a voltage reference chip. VCC_5.3V is filtered by C301 (1μF) and C302 (100nF) and then connected to the VIN pin to output REF_VCC_5V. C303 (100nF) is used to stabilize the output voltage, providing a stable 5V reference voltage for the circuit.

[0067] In addition, C271 (100nF) is used to filter the AVDD_sensor power supply, and R272 (2.2KΩ, 0603_RES package) is used for signal matching or current limiting. The entire circuit involves power conversion, signal processing, and communication functions, and is applied in systems that require sensor data acquisition and processing.

[0068] like Figure 11 As shown, the voltage measurement circuit in the voltage and current measurement section consists of resistors R311 and R312 (both 51Ω), and capacitors C313 (1mF), C314 (100nF), and C315 (1mF). AIN+ and GND are the input ports, and 7799_AIN+ and 7799_AIN- are the output ports connected to subsequent circuits. The principle is based on voltage division using resistors and filtering using capacitors. Resistors R311 and R312 divide the input voltage, large capacitors C313 and C315 filter out low-frequency interference, and small capacitor C314 filters out high-frequency interference, resulting in cleaner voltage signals output to 7799_AIN+ and 7799_AIN-, facilitating subsequent measurements.

[0069] like Figure 11 As shown, the current measurement in the voltage and current measurement circuit consists of resistors R313 and R314 (both 51Ω), and capacitors C316 (1mF), C317 (100nF), and C318 (1mF). LOOP-measure is the current input path, and 7799_AIN2+ and 7799_AIN2- are the output ports. Principle: Based on the resistor sampling principle, R313 and R314 act as sampling resistors to convert the current signal into a voltage signal. This signal is then filtered by capacitors C316, C317, and C318 to remove interference components before being output to 7799_AIN2+ and 7799_AIN2- for further processing.

[0070] Figure 11 The left side consists of a voltage divider circuit composed of resistors R322 (20KΩ) and R323 (2KΩ), which divides the input voltage of loop+ / AVDD_sensor_IN and outputs it to 7799_AIN3+. Figure 11 The right side section contains the op-amp U34 (AD8148ABRMZ) circuit. R341 (1Ω) is used for signal matching or current limiting, and C341 (100nF) is used for power supply filtering. The op-amp amplifies and buffers the signal, processing the input signal before outputting it from 7799_AIN3+.

[0071] like Figure 12 As shown, Figure 12 The upper circuit is an analog-to-digital converter circuit, in which the AD7799 chip is a low-power, high-precision analog-to-digital converter (ADC).

[0072] like Figure 12 The lower circuit shown is a voltage reference circuit, which works in conjunction with the AD7799 to provide a reference voltage.

[0073] like Figure 13-18 As shown, Figure 13-18 This is a circuit diagram of the multiple output selection circuit of this utility model. The input terminal of the multiple output selection circuit is electrically connected to the MCU main control circuit, and the output terminal is connected to each sensor. The output line of the multiple output selection circuit is controlled by the MCU main control circuit to calibrate the pressure sensor.

[0074] The multiple output selection circuit includes:

[0075] Connector J2 has multiple input / output ports and is connected to the MCU;

[0076] The communication interface chip U13, which is connected to the MCU, is used for RS-485 communication;

[0077] The multi-channel optocoupler circuit connected to the connector J2;

[0078] A relay circuit connected to the communication interface chip U13, which is connected to a multi-channel optocoupler circuit, is used to control the switching of the multi-channel optocoupler circuit.

[0079] A switching circuit connected to the MCU, which is also connected to the relay circuit.

[0080] The switching circuit includes a voltage regulator circuit, a current detection and amplification circuit connected to the voltage regulator circuit, and a single-channel inverting circuit.

[0081] Specifically, such as Figure 13 As shown, Figure 13This is a switching circuit. In this circuit, the voltage regulator is connected to a 24V power supply (LDO24V), which is the output voltage of a linear regulator. The emitter of transistor Q211 is connected to the LDO24V power supply, and a diode ZD222 (a Zener diode) is connected between its emitter and collector for voltage regulation to prevent overvoltage from damaging subsequent circuits. A resistor R223 is connected between the emitter and base of diode ZD222.

[0082] The collector of transistor Q212 is connected to the base of transistor Q211. The base of transistor Q212 is connected to resistor R222. The other end of resistor R222 is connected to the OWI_TX_MCU circuit of the MCU. The emitter of transistor Q212 is connected to resistor R224. The other end of resistor R224 is grounded and connected to one end of capacitor C222. The other end of capacitor C222 is connected to the power supply LDO24V.

[0083] The collector of transistor Q211 is connected to resistor R225, the other end of resistor R225 is connected to the collector of transistor Q213, the emitter of transistor Q213 is grounded, and its base is connected to resistor R221.

[0084] The other end of the resistor R221 is connected to the negative terminal of the diode ZD223, and the positive terminal of the diode ZD223 is grounded.

[0085] The OWI_TX_MCU circuit is also connected to the negative terminal of diode ZD221, while the positive terminal of diode ZD221 is grounded.

[0086] The OWI_TX_MCU circuit is also connected to a single-channel inverter circuit, which is equipped with a single-channel inverter chip U22. The single-channel inverter chip U22 (MC74VHC1G04) is used for signal inversion. Its pin 5 is connected to the power supply (VCC_5V), and its pin 4 outputs the inverted signal.

[0087] The single-channel inverter chip U22 has a capacitor C221 connected to pin 5, and the other end of the capacitor C221 is grounded. Pin 5 of the single-channel inverter chip U22 is connected to VCC_5V voltage.

[0088] The collector of the transistor Q211 is connected to a test point in the circuit.

[0089] The collector of the transistor Q211 is also connected to a fuse F211, and the other end of the fuse F211 is connected to resistors R215 and R216 respectively.

[0090] The other end of resistor R215 outputs the LOOP+ circuit, and the other end of resistor R216 is connected to pin 8 of chip U21. Chip U21 is a voltage comparator chip, model ina200AIDR_SOIC8. Pin 8 of chip U21 is also connected to the first end of capacitor C212 and the compare VIN+ circuit. The second end of capacitor C212 is connected to resistor R217, and the other end of resistor R217 is connected to the LOOP+ circuit.

[0091] Pin 7 of the chip U21 is connected to the compare VIN- circuit and the second end of capacitor C212.

[0092] Pin 6 of the chip U21 is connected to the OWI_RX_MCU pin of the MCU, and pin 6 is also connected to resistor R214. The other end of resistor R214 is connected to the VCC_5V circuit.

[0093] The chip U21 has a V+ pin, an OUT pin, a CMPin pin, and a GND pin. Its V+ pin is connected to capacitor C211, and the other end of capacitor C211 is grounded. The OUT pin is connected to the first end of resistor R211. The GND pin is grounded and also connected to the first end of resistor R212. The second ends of resistor R212, resistor R211, and the CMPin pin of chip U21 are interconnected and connected to the first end of resistor R213. The second end of resistor R213 is connected to pin 6 of chip U21.

[0094] The CMPin pin is also connected to a test point.

[0095] Figure 13 In the circuit, the 24V LDO power supply is regulated by diode ZD222 to provide a stable voltage for the circuit, and fuse F211 provides overcurrent protection. Transistors Q211, Q212, and Q213 constitute the signal processing circuit, amplifying or level-shifting the OWI_TX_MCU signal. Comparator chip U21 compares the t_CMPin input signal with the set reference and outputs the result to OWI_RX_MCU. Single-channel inverter chip U22 inverts the signal, and the capacitors and resistors work together to complete auxiliary functions such as filtering, decoupling, and voltage division.

[0096] like Figure 14As shown, the 5.5V power supply (VCC_5.5V_relay) is connected to the optocoupler relay AQW212 (U18) via R181 and R182 to achieve electrical isolation. Current (current_in) flows into the circuit and is output through pin 5 of U18. R317 is connected to the measurement node LOOP-measure. Although R218 and R219 are not connected, R318-R321 form a high-precision resistor network for current measurement. D192 (TVS diode) protects the circuit from overvoltage surges. The overall circuit achieves current measurement, electrical isolation, and overvoltage protection functions.

[0097] like Figure 15 As shown, the AQW212 optocoupler relay provides electrical isolation, and the input voltage can be connected and output through its pins; D201 and D202 transient voltage suppression diodes protect the circuit from transient high voltage impacts; the sensor_VQUT_0-10V_Ctrl signal is clamped by the ZD331 Zener diode and input to the AD719 analog-to-digital converter through the R331 resistor, and the sensor_VOUT_0-10V signal is also connected to the AD719 after being divided by the R315 and R316 resistors. The AD719 converts the relevant analog signals into digital signals.

[0098] like Figure 16 As shown, this circuit mainly utilizes AQW212 and AQY211G2S optocouplers. The HPW_IN signal is input via a resistor, and the optocoupler controls the connection of its output pins based on the input signal state. This enables the switching or level distribution of different signal lines such as LOOP+, LOOP-, VCC_HPW, GND, and sensor_VOUT, thereby controlling the circuit connection and transmission of sensor-related power supplies (such as AVDD_sensor) and signals (such as sensor_VOUT_0-10V and sensor_VOUT_0-5V).

[0099] like Figure 17 As shown, this circuit uses the MAX4820 chip as its core. VCC is connected to a 5V power supply and filtered by capacitor C131. 4820_CS9, 4820_DIN, and 4820_SCLK are connected to the chip's CS, DIN, and SCLK pins respectively for control and data transmission. The SET and RESET pins can be used for corresponding function settings. The chip processes the input signal through internal logic and outputs the processed signal from the DOUT and OUT8 pins. It also works in conjunction with external circuits (such as relay circuits connected to related pins like VCC_5.5V_relay) to achieve specific functions.

[0100] like Figure 18As shown, this circuit utilizes the 96 pins of the J2 connector to achieve various signal inputs and controls. Pins such as "currentin" and "voltagein" are used for inputting current and voltage signals; "485_A" and "485_B" enable 485 communication; "MCUADDR0-MCUADDR3" are used for MCU address settings; "LOOP+Ctrl" and "LOOP-Ctrl" are used to control related loops; and "sensorVOUT0-10VCtrl" and "sensorVOUT0-5VCtrl" control the sensor output voltage. Overall, it realizes signal input, communication, and control functions.

[0101] In summary, this utility model's automatic batch calibration pressure sensor circuit can calibrate sensors with high precision. Digital control eliminates human error, improving calibration accuracy and increasing batch calibration efficiency. This utility model's automatic batch calibration pressure sensor circuit has strong batch processing capabilities, avoids environmental interference, and has stable calibration capabilities. This utility model's automatic batch calibration pressure sensor circuit reduces manual intervention, lowering labor costs. This utility model's automatic batch calibration pressure sensor circuit supports remote control and data recording.

[0102] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the contents of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.

Claims

1. An automatic batch calibration circuit for pressure sensors, characterized in that, include: The MCU main control circuit is used to execute program instructions stored in memory, process input signals, and control external devices through output signals; The data acquisition circuit is electrically connected to the MCU main control circuit. The data acquisition circuit converts analog signals into digital signals, acquires and processes them, and then transmits them to the MCU main control circuit. The circuit has multiple output selection circuits. The input terminal is electrically connected to the MCU main control circuit, and the output terminal is connected to each sensor. The output line of the multiple output selection circuits is controlled by the MCU main control circuit to calibrate the pressure sensor.

2. The automatic batch calibration pressure sensor circuit according to claim 1, characterized in that, The MCU main control circuit includes an MCU, which has a multi-channel selectable output circuit. The MCU is connected to a storage chip U24, a crystal oscillator circuit, a reset connector, a filter circuit, and an integrated isolated data transceiver circuit.

3. The automatic batch calibration pressure sensor circuit according to claim 2, characterized in that, The MCU used is MC9S08A260.

4. The automatic batch calibration pressure sensor circuit according to claim 2, characterized in that, The integrated isolated data transceiver circuit uses an RS-485 signal transmission circuit.

5. The automatic batch calibration pressure sensor circuit according to claim 2, characterized in that, The data acquisition circuit includes: A signal conversion circuit connected to the MCU and used to convert analog signals into digital signals; The power supply circuit has a first step-down circuit and a second step-down circuit connected to the output terminal of the first step-down circuit. The second step-down circuit outputs a reference voltage, which is supplied to the signal conversion circuit. A voltage and current measurement circuit is connected to the output terminal of the signal conversion circuit to detect the voltage and current in the signal conversion circuit. The analog-to-digital converter circuit has its input terminal connected to the MCU, which is used to communicate with external devices. It receives the voltage and current signals conditioned by the front end and converts them into digital signals for output. The voltage reference circuit is electrically connected to the MCU to provide a stable reference level for the system and ensure the accuracy of the measurement.

6. The automatic batch calibration pressure sensor circuit according to claim 2, characterized in that, The multiple output selection circuit includes: Connector J2 has multiple input / output ports and is connected to the MCU; The communication interface chip U13, which is connected to the MCU, is used for RS-485 communication; The multi-channel optocoupler circuit connected to the connector J2; A relay circuit connected to the communication interface chip U13, which is connected to a multi-channel optocoupler circuit, is used to control the switching of the multi-channel optocoupler circuit. A switching circuit connected to the MCU, which is also connected to the relay circuit.

7. The automatic batch calibration pressure sensor circuit according to claim 6, characterized in that, The switching circuit includes a voltage regulator circuit, a current detection and amplification circuit connected to the voltage regulator circuit, and a single-channel inverting circuit.

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