High-precision pressure gauge

Abstract

The utility model provides a high-precision pressure gauge, and belongs to the technical field of instruments and meters. The high-precision pressure gauge comprises a switch module, a pressure sensor, an automatic calibration module, a signal processing module, a main control module and a display module, a first end of the switch module is connected with a power supply, a second end of the switch module is connected with a power supply end of the pressure sensor, an output end of the pressure sensor is connected with an input end of the signal processing module, and an output end of the signal processing module is connected with the master control module; the power supply end of the automatic calibration module is connected with the second end of the switch module, the control end of the automatic calibration module is connected with the main control module, and the output end of the automatic calibration module is connected with the input end of the signal processing module; the master control module is connected with the display module. According to the invention, the precision of pressure detection can be improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of instruments and meters, and in particular to a high-precision pressure gauge. Background Art

[0002] Pressure gauges are critical pressure measuring instruments in numerous industrial fields, including chemical processing, thermal networks, oil and gas transmission, and water and gas supply systems. Their accuracy and stability are directly related to the accuracy of industrial process control and measurement. However, traditional pressure gauges often experience performance changes over time due to internal component changes, resulting in non-zero output before pressure testing, seriously affecting pressure detection accuracy. Utility Model Content

[0003] The embodiments of the present disclosure provide a high-precision pressure gauge to improve the accuracy of pressure detection.

[0004] The embodiment of the present disclosure provides a high-precision pressure gauge, comprising: a switch module, a pressure sensor, an automatic calibration module, a signal processing module, a main control module and a display module;

[0005] The first end of the switch module is used to connect to the power supply, the second end of the switch module is connected to the power supply end of the pressure sensor, the output end of the pressure sensor is connected to the input end of the signal processing module, and the output end of the signal processing module is connected to the main control module;

[0006] The power supply end of the automatic calibration module is connected to the second end of the switch module, the control end of the automatic calibration module is connected to the main control module, and the output end of the automatic calibration module is connected to the input end of the signal processing module;

[0007] The main control module is connected to the display module.

[0008] In an exemplary embodiment of the present disclosure, it further includes: a constant current module;

[0009] The first end of the constant current module is connected to the second end of the switch module, and the second end of the constant current module is connected to the power supply end of the pressure sensor.

[0010] In an exemplary embodiment of the present disclosure, the signal processing module includes:

[0011] Resistor R1, resistor R2, op amp U1, resistor R3, resistor R4 and capacitor C2;

[0012] The first end of the resistor R1 is connected to the output end of the pressure sensor, and the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1;

[0013] The first end of the resistor R2 is connected to the output end of the automatic calibration module, the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U1, the output end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U1 through the resistor R3, and the output end of the operational amplifier U1 is connected to the first end of the resistor R4; the second end of the resistor R4 is grounded through the capacitor C2, and the second end of the resistor R4 is connected to the main control module.

[0014] In an exemplary embodiment of the present disclosure, the signal processing module further includes: an operational amplifier U3;

[0015] The non-inverting input terminal of the operational amplifier U3 is connected to the output terminal of the pressure sensor, the output terminal of the operational amplifier U3 is connected to the inverting input terminal of the operational amplifier U3, and the output terminal of the operational amplifier U3 is connected to the first terminal of the resistor R1.

[0016] In an exemplary embodiment of the present disclosure, the automatic calibration module includes: a digital potentiometer U4, a resistor R6, a transistor Q1 and an operational amplifier U2;

[0017] The control end of the digital potentiometer U4 is connected to the main control module, the power supply end of the digital potentiometer U4 is connected to the second end of the switch module, the high potential end of the digital potentiometer U4 is connected to the power supply end of the digital potentiometer U4, the low potential end of the digital potentiometer U4 is grounded, and the output end of the digital potentiometer U4 is connected to the first end of the resistor R2;

[0018] The first end of the resistor R6 is connected to the power supply end of the digital potentiometer U4, the second end of the resistor R6 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the first end of the resistor R6, the emitter of the transistor Q1 is connected to the non-inverting input end of the operational amplifier U2, the inverting input end of the operational amplifier U2 is used to connect to the reference voltage, and the output end of the operational amplifier U2 is connected to the clock end of the digital potentiometer U4.

[0019] In an exemplary embodiment of the present disclosure, the automatic calibration module further includes: a resistor R9, a resistor R8 and a voltage regulator diode D1;

[0020] The first end of the resistor R9 is connected to the collector of the transistor Q1, the second end of the resistor R9 is grounded through the resistor R8, the second end of the resistor R9 is connected to the inverting input terminal of the operational amplifier U2, the cathode of the voltage regulator D1 is connected to the second end of the resistor R9, and the anode of the voltage regulator D1 is grounded.

[0021] In an exemplary embodiment of the present disclosure, the switch module includes: a key switch K1;

[0022] A first end of the key switch K1 is used to connect to a power supply VCC, and a second end of the key switch K1 is connected to a power supply end of the pressure sensor.

[0023] In an exemplary embodiment of the present disclosure, the constant current module includes: an operational amplifier U5, a resistor R11, a resistor R10 and a transistor Q2;

[0024] The non-inverting input terminal of the operational amplifier U5 is connected to the second end of the switch module, the output terminal of the operational amplifier U5 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the ground terminal of the pressure sensor, the emitter of the transistor Q2 is grounded through the resistor R10, and the emitter of the transistor Q2 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R11.

[0025] The beneficial effects of a high-precision pressure gauge provided by the embodiment of the present disclosure are as follows: the switch module of the embodiment of the present disclosure controls the power supply, ensures the stable power supply of the pressure gauge, and enables the pressure sensor and the automatic calibration module to work normally. The pressure sensor can convert the pressure signal into an electrical signal for output, and the signal processing module amplifies and filters the electrical signal that is weak and easily affected by the environment, thereby improving the signal quality, ensuring that the signal received by the main control module is stable and reliable, and helping to improve the detection accuracy. The automatic calibration module can automatically calibrate the pressure sensor before detecting the pressure, ensuring that the initial state of the output signal is zero, and effectively avoiding the influence of the initial non-zero signal on the subsequent pressure detection accuracy. Finally, the main control module transmits the detection signal to the display module for intuitive display, making it convenient for users to read the results, and realizing high-precision pressure detection and convenient reading as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0027] Figure 1 This is a structural block diagram of a high-precision pressure gauge provided by an embodiment of the present disclosure;

[0028] Figure 2 is a structural block diagram of another high-precision pressure gauge provided by an embodiment of the present disclosure;

[0029] Figure 3 This is a circuit diagram of a high-precision pressure gauge provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] To help those skilled in the art better understand this solution, the following will clearly describe the technical solutions in the embodiments of this solution in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of this solution, not all of it. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of this solution.

[0031] Throughout the specification, claims, and accompanying figures of this solution, the term "including" and any variations thereof mean "including, but not limited to," and are intended to cover non-exclusive inclusions and are not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish between different objects, not to describe a specific order.

[0032] The following describes the implementation of the present disclosure in detail with reference to the accompanying drawings:

[0033] Figure 1 This is a schematic diagram of the structure of a high-precision pressure gauge provided by an embodiment of the present disclosure. Figure 1 The high-precision pressure gauge includes: a switch module, a pressure sensor, an automatic calibration module, a signal processing module, a main control module and a display module; the first end of the switch module is used to connect to the power supply, the second end of the switch module is connected to the power supply end of the pressure sensor, the output end of the pressure sensor is connected to the input end of the signal processing module, and the output end of the signal processing module is connected to the main control module; the power supply end of the automatic calibration module is connected to the second end of the switch module, the control end of the automatic calibration module is connected to the main control module, and the output end of the automatic calibration module is connected to the input end of the signal processing module; the main control module is connected to the display module.

[0034] In this embodiment, the pressure gauge is a commonly used pressure measuring instrument in the chemical industry and is widely used in industrial process control and measurement. It is found in almost all industrial processes and scientific research fields, and can be found in thermal pipelines, oil and gas transmission, water and gas supply systems, and other fields. In actual applications, the performance of the components within the pressure gauge may change over time, resulting in the pressure gauge output being non-zero before pressure testing, thereby affecting the accuracy of pressure testing.

[0035] In this embodiment, the switch module controls the power supply to the entire pressure gauge. Its first terminal connects to a power source to obtain electrical energy, while its second terminal transmits this energy to the power supply terminals of the pressure sensor and the automatic calibration module, providing power support for their normal operation. Once powered, the pressure sensor is operational.

[0036] The pressure sensor converts the pressure signal into an electrical output signal. The electrical signal output by the pressure sensor is processed by the signal processing module and then sent to the main control module. Because the electrical signal output by the pressure sensor is relatively weak and easily affected by the surrounding environment, the signal processing module can amplify and filter the electrical signal output by the pressure sensor. Amplification can enhance the strength of the electrical signal, making it easier for subsequent modules to identify and process it. Filtering can remove invalid signal components such as clutter caused by environmental interference, thereby ensuring that the electrical signal received by the main control module is stable and reliable, helping to improve the accuracy of pressure detection results.

[0037] In actual application scenarios, due to the influence of some uncontrollable factors, the pressure sensor may also generate an electrical signal even before the pressure is detected (that is, when no external pressure is applied or it is in the initial state). In this case, its output is not 0. The main control module can continuously receive the electrical signal from the pressure sensor. Once it finds that the output of the pressure sensor is not 0 before the pressure is detected, the main control module can send a control instruction to the automatic calibration module. After receiving the instruction, the automatic calibration module can perform a calibration operation and then send the calibrated signal to the input end of the signal processing module. After processing by the signal processing module, the electrical signal finally transmitted to the main control module can be 0 before the pressure is detected, avoiding the adverse effects of the non-zero signal in the initial state on the subsequent pressure detection accuracy, and ensuring that the entire pressure gauge can perform pressure detection with high precision.

[0038] In actual applications, the main control module can transmit the pressure detection signal received to the display module, and the display module can intuitively display the pressure value, making it convenient for users to read the pressure detection results.

[0039] From the above, it can be concluded that the switch module of this embodiment controls the power supply, ensures the stable power supply of the pressure gauge, and enables the pressure sensor and the automatic calibration module to work normally. The pressure sensor can convert the pressure signal into an electrical signal for output, and the signal processing module amplifies and filters the electrical signal that is weak and easily affected by the environment, thereby improving the signal quality and ensuring that the signal received by the main control module is stable and reliable, which is conducive to improving the detection accuracy. The automatic calibration module can automatically calibrate the pressure sensor before detecting the pressure, ensuring that the initial state of the output signal is zero, and effectively avoiding the influence of the initial non-zero signal on the subsequent pressure detection accuracy. Finally, the main control module transmits the detection signal to the display module for intuitive display, making it convenient for users to read the results, and realizing high-precision pressure detection and convenient reading as a whole.

[0040] like Figure 2 As shown, in one embodiment of the present disclosure, it also includes: a constant current module; the first end of the constant current module is connected to the second end of the switch module, and the second end of the constant current module is connected to the power supply end of the pressure sensor.

[0041] In this embodiment, the constant current module is used to ensure that the current flowing to the pressure sensor is stable. Since the performance and measurement accuracy of the pressure sensor are sensitive to the stability of the power supply current during operation, if the power supply current fluctuates, it may cause the electrical signal output by the pressure sensor to deviate or become unstable. The constant current module can convert the input electrical energy into a stable constant current and output it to the pressure sensor, so that the pressure sensor can operate under a stable current supply. In this way, the pressure sensor can more accurately convert the detected pressure signal into an electrical signal output, and the quality of the electrical signal received by the subsequent signal processing module can also be further guaranteed, which is beneficial for the entire pressure gauge system to achieve high-precision pressure measurement, reduce the measurement error and uncertainty introduced by the unstable power supply current, and improve the reliability and accuracy of the pressure gauge under various working conditions.

[0042] like Figure 3 As shown, in one embodiment of the present disclosure, the signal processing module includes: a resistor R1, a resistor R2, an operational amplifier U1, a resistor R3, a resistor R4 and a capacitor C2; the first end of the resistor R1 is connected to the output end of the pressure sensor, and the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1; the first end of the resistor R2 is connected to the output end of the automatic calibration module, the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U1, the output end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U1 through the resistor R3, and the output end of the operational amplifier U1 is connected to the first end of the resistor R4; the second end of the resistor R4 is grounded through the capacitor C2, and the second end of the resistor R4 is connected to the main control module.

[0043] In this embodiment, before pressure is measured, the electrical signal output by the pressure sensor first enters the signal processing module and is transmitted via resistor R1 to the non-inverting input of op amp U1. Simultaneously, the calibration signal output by the automatic calibration module is transmitted via resistor R2 to the inverting input of op amp U1. This allows the original pressure signal and the calibration signal to be superimposed at the input of op amp U1, calibrating the pressure gauge and ensuring that the voltage output by op amp U1 is zero before pressure measurement.

[0044] After calibration, the automatic calibration module will maintain the output of a voltage signal, which is applied to the inverting input of op amp U1 as a reference voltage. When pressure detection is officially performed, the non-inverting input of op amp U1 receives the voltage signal output by the pressure sensor. In this embodiment, the pressure sensor can be represented by U6. At this time, op amp U1 forms a differential amplifier circuit. When there is a small potential difference between the non-inverting input and the inverting input of op amp U1, op amp U1 can output a corresponding amplified voltage signal, thereby amplifying the weak electrical signal of the pressure sensor and enhancing the signal strength so that the subsequent main control module can more accurately identify it. At the same time, the differential amplifier circuit can amplify useful differential-mode signals and suppress useless common-mode signals, further improving the detection accuracy of the circuit.

[0045] Among them, resistor R4 and capacitor C2 form a filtering circuit, which can filter out high-frequency clutter in the signal and only allow low-frequency signals (i.e., effective pressure signal components) to be transmitted to the main control module through resistor R4, thereby removing high-frequency noise caused by factors such as environmental interference, ensuring that the signal received by the main control module is stable and reliable, and further improving the accuracy and precision of pressure measurement.

[0046] From the above, it can be concluded that this embodiment, through the combination of operational amplifier U1 and related resistors, can not only use the signal output by the automatic calibration module and the pressure sensor signal for superposition processing before detection to achieve pressure gauge calibration and ensure that the initial output voltage is 0, but also form a differential amplifier circuit during detection to effectively amplify weak electrical signals and suppress common-mode signals, thereby enhancing signal strength and accuracy.

[0047] like Figure 3 As shown, in one embodiment of the present disclosure, the signal processing module further includes: an operational amplifier U3; the non-inverting input terminal of the operational amplifier U3 is connected to the output terminal of the pressure sensor, the output terminal of the operational amplifier U3 is connected to the inverting input terminal of the operational amplifier U3, and the output terminal of the operational amplifier U3 is connected to the first end of the resistor R1.

[0048] In this embodiment, the operational amplifier U3 forms a voltage follower, which can buffer and isolate the electrical signal output by the pressure sensor, preventing the subsequent circuit from generating adverse load effects on the pressure sensor, and ensuring stable operation of the pressure sensor.

[0049] like Figure 3 As shown, in one embodiment of the present disclosure, the automatic calibration module includes: a digital potentiometer U4, a resistor R6, a transistor Q1 and an operational amplifier U2; the control end of the digital potentiometer U4 is connected to the main control module, the power supply end of the digital potentiometer U4 is connected to the second end of the switch module, the high potential end of the digital potentiometer U4 is connected to the power supply end of the digital potentiometer U4, the low potential end of the digital potentiometer U4 is grounded, and the output end of the digital potentiometer U4 is connected to the first end of the resistor R2; the first end of the resistor R6 is connected to the power supply end of the digital potentiometer U4, the second end of the resistor R6 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the first end of the resistor R6, the emitter of the transistor Q1 is connected to the non-inverting input end of the operational amplifier U2, the inverting input end of the operational amplifier U2 is used to connect to the reference voltage, and the output end of the operational amplifier U2 is connected to the clock end of the digital potentiometer U4.

[0050] In this embodiment, before detecting the pressure, if the voltage output by the pressure sensor U6 is not 0, the voltage signal output by the pressure sensor U6 is output as a voltage signal to the main control module after passing through the signal processing module. At this time, the main control module can send a control signal to the digital potentiometer U4 according to the size of the received voltage signal, thereby changing the voltage at the output end (RW pin) of the digital potentiometer U4, that is, changing the reference voltage of the inverting input end of the operational amplifier U1, so that the output of the operational amplifier U1 is 0.

[0051] Before the main control module sends a control command to digital potentiometer U4, it must first send a clock pulse to the clock terminal (CLK pin) of digital potentiometer U4 to put digital potentiometer U4 into operation. When the switch module is closed, digital potentiometer U4 is connected to the VCC power supply. At the same time, the VCC power supply is applied to the base of transistor Q1 through resistor R6, causing the transistor to saturate and conduct. At this time, the VCC power supply passes through resistor R6, transistor Q1, and resistor R7, and is applied to the non-inverting input terminal of op amp U2. Op amp U2 forms a comparator. When transistor Q1 is turned on, the voltage at the non-inverting input terminal of op amp U2 is greater than the voltage at its inverting input terminal. Op amp U2 outputs a high level to the clock terminal (CLK pin) of digital potentiometer U4. At this time, digital potentiometer U4 can accept the control command from the main control module and then change the voltage at the output terminal of digital potentiometer U4 based on the control command from the main control module, thereby achieving automatic calibration.

[0052] As can be seen from the above, this embodiment utilizes components such as digital potentiometer U4, transistor Q1, and op amp U2. Before pressure detection, when the pressure sensor outputs a non-zero voltage, the main control module controls digital potentiometer U4 based on the received signal to adjust the reference voltage at the inverting input of op amp U1, returning the output of op amp U1 to zero, achieving precise calibration. The main control module activates the digital potentiometer U4's operating state via a clock pulse, and the circuit utilizes a comparator formed by transistor Q1 and op amp U2, ensuring an efficient and orderly calibration process, effectively improving the pressure gauge's measurement accuracy and reliability.

[0053] like Figure 3 As shown, in one embodiment of the present disclosure, the automatic calibration module also includes: a resistor R9, a resistor R8 and a voltage regulator D1; the first end of the resistor R9 is connected to the collector of the transistor Q1, the second end of the resistor R9 is grounded through the resistor R8, the second end of the resistor R9 is connected to the inverting input terminal of the operational amplifier U2, the cathode of the voltage regulator D1 is connected to the second end of the resistor R9, and the anode of the voltage regulator D1 is grounded.

[0054] In this embodiment, resistors R9 and R8 form a voltage divider circuit, which is used to provide a stable reference voltage for the inverting input of op amp U2. When transistor Q1 is turned on, the VCC power supply, after passing through resistor R6, transistor Q1, and resistor R9, forms a specific voltage value at the voltage divider point between resistors R9 and R8. This voltage acts together with voltage regulator D1. Voltage regulator D1 acts as a voltage stabilizer, further ensuring that the reference voltage at the inverting input of op amp U2 remains stable at a specific value. This allows the comparator formed by op amp U2 to more accurately judge and output the corresponding voltage level based on the voltage changes at the non-inverting input. This ensures that the digital potentiometer U4 can be calibrated stably and reliably according to the instructions of the main control module, thereby improving the accuracy and stability of the entire automatic calibration module.

[0055] like Figure 3 As shown, in one embodiment of the present disclosure, the switch module includes: a key switch K1; a first end of the key switch K1 is used to connect to a power supply VCC, and a second end of the key switch K1 is connected to a power supply end of the pressure sensor.

[0056] In this embodiment, when the push switch K1 is pressed, its internal contacts are closed, and a path is formed between the power supply VCC and the power supply end of the pressure sensor. Electric energy can be transmitted from the power supply VCC to the pressure sensor, thereby providing the pressure sensor with the power required for normal operation, enabling it to convert the detected pressure signal into an electrical signal, and then start a series of subsequent signal processing, calibration, and display related work processes of the entire pressure gauge; when the push switch K1 is popped up and disconnected, the circuit is broken, and the pressure sensor and other related modules stop working due to loss of power supply, thereby realizing convenient control of whether the pressure gauge is powered on or not.

[0057] like Figure 3 As shown, in one embodiment of the present disclosure, the constant current module includes: an operational amplifier U5, a resistor R11, a resistor R10 and a transistor Q2; the non-inverting input terminal of the operational amplifier U5 is connected to the second end of the switch module, the output terminal of the operational amplifier U5 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the ground terminal of the pressure sensor, the emitter of the transistor Q2 is grounded through the resistor R10, and the emitter of the transistor Q2 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R11.

[0058] In this embodiment, in the initial state, since transistor Q2 is not conducting or conducting only weakly, the current flowing through resistor R10 is small, the voltage at the inverting input of op amp U5 is low, and op amp U5 outputs a high level, gradually turning on transistor Q2. As the conduction level of transistor Q2 increases, the emitter current increases, the voltage drop across resistor R10 increases, and the voltage at the inverting input of op amp U5 rises. When the voltage at the inverting input approaches the voltage at the non-inverting input, op amp U5 outputs a stable level, causing transistor Q2 to operate in a stable conduction state.

[0059] Since the emitter current of the transistor Q2 is mainly determined by the resistor R10 and the resistor R11, and the current is relatively stable, the stable current flows into the ground end of the pressure sensor through the collector of the transistor Q2, thereby providing a stable constant current for the pressure sensor, ensuring that the pressure sensor works under the condition of stable current, which is conducive to improving the accuracy and stability of the measurement and reducing the measurement error caused by the fluctuation of the power supply current.

[0060] The above examples are only used to illustrate the technical solutions of the present disclosure, but not to limit it; although the present disclosure has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A high-precision pressure gauge, characterized in that: include: Switch module, pressure sensor, automatic calibration module, signal processing module, main control module and display module; The first end of the switch module is used to connect to the power supply, the second end of the switch module is connected to the power supply end of the pressure sensor, the output end of the pressure sensor is connected to the input end of the signal processing module, and the output end of the signal processing module is connected to the main control module; The power supply end of the automatic calibration module is connected to the second end of the switch module, the control end of the automatic calibration module is connected to the main control module, and the output end of the automatic calibration module is connected to the input end of the signal processing module; The main control module is connected to the display module.

2. A high-precision pressure gauge according to claim 1, characterized in that: Also includes: Constant current module; The first end of the constant current module is connected to the second end of the switch module, and the second end of the constant current module is connected to the power supply end of the pressure sensor.

3. A high-precision pressure gauge according to claim 1, characterized in that: The signal processing module includes: Resistor R1, resistor R2, op amp U1, resistor R3, resistor R4 and capacitor C2; The first end of the resistor R1 is connected to the output end of the pressure sensor, and the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1; The first end of the resistor R2 is connected to the output end of the automatic calibration module, the second end of the resistor R2 is connected to the inverting input end of the operational amplifier U1, the output end of the operational amplifier U1 is connected to the inverting input end of the operational amplifier U1 through the resistor R3, and the output end of the operational amplifier U1 is connected to the first end of the resistor R4; the second end of the resistor R4 is grounded through the capacitor C2, and the second end of the resistor R4 is connected to the main control module.

4. A high-precision pressure gauge according to claim 3, characterized in that: The signal processing module further includes: an operational amplifier U3; The non-inverting input terminal of the operational amplifier U3 is connected to the output terminal of the pressure sensor, the output terminal of the operational amplifier U3 is connected to the inverting input terminal of the operational amplifier U3, and the output terminal of the operational amplifier U3 is connected to the first terminal of the resistor R1.

5. A high-precision pressure gauge according to claim 3, characterized in that: The automatic calibration module includes: a digital potentiometer U4, a resistor R6, a transistor Q1 and an operational amplifier U2; The control end of the digital potentiometer U4 is connected to the main control module, the power supply end of the digital potentiometer U4 is connected to the second end of the switch module, the high potential end of the digital potentiometer U4 is connected to the power supply end of the digital potentiometer U4, the low potential end of the digital potentiometer U4 is grounded, and the output end of the digital potentiometer U4 is connected to the first end of the resistor R2; The first end of the resistor R6 is connected to the power supply end of the digital potentiometer U4, the second end of the resistor R6 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the first end of the resistor R6, the emitter of the transistor Q1 is connected to the non-inverting input end of the operational amplifier U2, the inverting input end of the operational amplifier U2 is used to connect to the reference voltage, and the output end of the operational amplifier U2 is connected to the clock end of the digital potentiometer U4.

6. A high-precision pressure gauge according to claim 5, characterized in that: The automatic calibration module also includes: a resistor R9, a resistor R8 and a voltage regulator tube D1; The first end of the resistor R9 is connected to the collector of the transistor Q1, the second end of the resistor R9 is grounded through the resistor R8, the second end of the resistor R9 is connected to the inverting input terminal of the operational amplifier U2, the cathode of the voltage regulator D1 is connected to the second end of the resistor R9, and the anode of the voltage regulator D1 is grounded.

7. A high-precision pressure gauge according to claim 1, characterized in that: The switch module includes: a key switch K1; A first end of the key switch K1 is used to connect to a power supply VCC, and a second end of the key switch K1 is connected to a power supply end of the pressure sensor.

8. A high-precision pressure gauge according to claim 2, characterized in that: The constant current module includes: an operational amplifier U5, a resistor R11, a resistor R10 and a transistor Q2; The non-inverting input terminal of the operational amplifier U5 is connected to the second end of the switch module, the output terminal of the operational amplifier U5 is connected to the base of the transistor Q2, the collector of the transistor Q2 is connected to the ground terminal of the pressure sensor, the emitter of the transistor Q2 is grounded through the resistor R10, and the emitter of the transistor Q2 is connected to the inverting input terminal of the operational amplifier U5 through the resistor R11.

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