CN116465545A - Automatic in-situ calibration system and method for pressure and differential pressure transmitter - Google Patents

Abstract

The invention relates to the technical field of remote calibration of force instruments and meters, and discloses an automatic in-situ calibration system and method of a pressure and differential pressure transmitter, wherein the system comprises a transmitter calibration pipeline system, a gas supply device, a measuring device and a controller; the gas supply device is used for supplying calibration gas to the transmitter calibration pipeline system; the transmitter calibration pipeline system comprises a differential pressure transmitter pipeline and a pressure transmitter pipeline, wherein the differential pressure transmitter pipeline and the pressure transmitter pipeline respectively provide a calibration interface connected with the air supply device for the differential pressure transmitter and the pressure transmitter; the measuring device is used for collecting analog quantity signals or digital quantity signals output by the differential pressure transmitter or the pressure transmitter; the controller calculates a measurement error of the differential pressure transmitter or the pressure transmitter according to the received analog quantity signal or the digital quantity signal. The invention can realize automatic in-situ calibration of the transmitter without leaving the installation position, so as to solve the problems of transmitter loss and incapability of on-line monitoring caused by periodical calibration of the existing transmitter.

Description

An automatic in-situ calibration system and method for pressure and differential pressure transmitters

technical field

The invention relates to the technical field of remote calibration of force instruments, in particular to an automatic in-situ calibration system and method for pressure and differential pressure transmitters.

Background technique

Transmitters (pressure transmitters, differential pressure transmitters) must be periodically calibrated to ensure the reliability of their values. The existing calibration mode requires the transmitter to be disassembled and sent to the laboratory for calibration. Repeated disassembly and transportation will cause the transmitter to be worn to varying degrees.

Moreover, periodic calibration loses the flexibility of calibration, and cannot monitor the performance indicators of pressure transmitters online in real time, which does not meet the needs of industrial intelligence.

Contents of the invention

The purpose of the present invention is to provide an automatic in-situ calibration system and method for pressure and differential pressure transmitters, which can realize automatic in-situ calibration of the transmitter without leaving the installation position, so as to solve the problems of transmitter loss and inability to monitor on-line caused by the periodic calibration of existing transmitters.

The present invention realizes through following technical scheme:

An automatic in-situ calibration system for pressure and differential pressure transmitters, including a transmitter calibration pipeline system, a gas supply device, a measuring device and a controller;

The gas supply device is used to provide calibration gas to the transmitter calibration pipeline system;

The transmitter calibration pipeline system includes a differential pressure transmitter pipeline, a pressure transmitter pipeline, a differential pressure transmitter and a pressure transmitter, the differential pressure transmitter pipeline provides a calibration interface for the differential pressure transmitter to be connected to the gas supply device, and the pressure transmitter pipeline provides a calibration interface for the pressure transmitter to be connected to the gas supply device;

The measuring device is used to collect analog signals or digital signals output by differential pressure transmitters or pressure transmitters;

The controller is communicatively connected with the gas supply device and the measuring device, and the controller is used to control the gas supply pressure of the gas supply device; the controller calculates the measurement error of the differential pressure transmitter or the pressure transmitter according to the received analog signal or digital signal.

The transmitter calibration pipeline system of the present invention provides a batch on-site calibration interface for pressure transmitters or differential pressure transformers; the gas supply device can provide high-precision (0-20) MPa gas as a standard gas source input, and the controller can be an industrial computer.

The present invention provides a pressure transmitter or a differential pressure transformer as a standard gas source by setting a transmitter calibration pipeline system and a gas supply device, and then directly collects the output signal of the pressure transmitter or differential pressure transformer through a measuring device and calculates it through a controller, thereby realizing automatic in-situ calibration of the pressure transmitter or differential pressure transmitter without leaving the installation position, and enabling online monitoring, which solves the problem of transmitter loss caused by periodic calibration of existing transmitters and cannot be monitored online.

Further, the gas supply device includes a gas supply pipeline, a pressure controller and a gas booster pump;

One end of the gas supply pipeline is connected to the gas source, and the other end is connected to the differential pressure transmitter pipeline and the calibration interface in the pressure transmitter pipeline;

Both the pressure controller and the gas booster pump are installed on the gas supply pipeline, the pressure controller communicates with the controller, and the controller controls the pressure controller to rise or fall to the required pressure point.

Further, the pipeline of the differential pressure transmitter includes a first drain pipe and a second drain pipe. One end of the first drain pipe and the second drain pipe are respectively connected to the low-pressure chamber end and the high-pressure chamber end of the differential pressure transmitter. The first drain pipe and the second drain pipe are connected through a connecting pipe, and a balance valve is arranged on the connecting pipe; the first drain pipe is provided with a first cut-off valve and a first drain valve in order of being far away from the differential pressure transmitter. drain valve;

The first drain pipe is provided with a first calibration pipe between the first shut-off valve and the connecting pipe, and the first calibration pipe is provided with a first calibration valve;

A second calibration pipe is provided between the second cut-off valve and the connecting pipe on the second drain pipe, and a second calibration valve is provided on the second calibration pipe; the second calibration pipe is connected to the air supply device.

Further, the pressure transmitter pipeline includes a third drain pipe, one end of the third drain pipe is connected to the pressure transmitter, and a third shut-off valve and a third drain valve are sequentially arranged on the third drain pipe in an order away from the pressure transmitter;

A third calibration pipe is provided on the third drain pipe between the third shut-off valve and the pressure transmitter, a third calibration valve is provided on the third calibration pipe, and the third calibration pipe is connected to the air supply device.

Further, the measuring device includes an analog signal acquisition module and a control unit;

The analog signal acquisition module is used to collect the analog signal output by the pressure transmitter or differential pressure transmitter, and transmit it to the control unit;

The control unit is communicatively connected with the analog signal acquisition module, the output end of the pressure transmitter, and the output end of the differential pressure transmitter, and the control unit is used to collect the digital signal output by the pressure differential pressure transmitter and the differential pressure transmitter;

The control unit transmits the collected digital signal or the received analog signal to the controller.

Further, the analog signal acquisition module includes a low-potential quick-plug connector, a transmitter switch and a digital multimeter;

The low-potential quick-plug connector is used to transmit the analog signal to the input channel of the transmitter switch; the digital multimeter is connected in series to the output channel of the transmitter switch, and the digital multimeter is used to measure the DC current signal.

The purpose of the transmitter changeover switch of the present invention is to be used for switching channels, and it can be the structure that only contains switching function, also can be to comprise the function of voltage conversion and switching channel switching, for example, can develop by 220V power supply to switch, and changeover switch carries out voltage transformation to 24V and then delivers to each channel.

Further, the analog signal acquisition module also includes a standard resistor, which is connected in series to the output channel of the transmitter changeover switch, and both ends of the standard resistor are connected to a digital multimeter for voltage measurement.

Further, the measuring device is installed in the integrated cabinet.

Further, the integrated cabinet is also provided with a power supply, a temperature and humidity sensor and a temperature and humidity adjustment device;

The power supply is used to supply power to the electrical equipment in the integrated cabinet;

Both the temperature and humidity sensor and the temperature and humidity adjustment device are electrically connected to the controller; the temperature and humidity sensor is used to collect the temperature and humidity in the integrated cabinet in real time, and transmit the collected temperature and humidity signals to the controller, and the controller controls the humidity adjustment device according to the received temperature and humidity to adjust the temperature and humidity in the integrated cabinet.

Further, the controller includes a calibration module and a data processing module;

The verification and calibration module is used to control the pressure controller in the gas supply device to perform boosting or stepping down; it is used to control the switching execution channel of the transmitter switching switch in the measuring device, and is used to read the analog signal and digital signal of the control unit in the measuring device;

The data processing module is used to obtain the analog signal and digital signal read by the verification and calibration module, compare the read analog signal and digital signal with the nominal value, calculate error, hysteresis, uncertainty, and generate an original record sheet.

Further, the controller also includes a file management module;

The file management module is used to store the original record table and calculation results generated by the data processing module.

Further, the controller also includes a device management module and a parameter setting module;

The equipment management module is used to manage and maintain the information of the schooled equipment and standard equipment;

The parameter setting module is used to configure and save calibration environment information, calibrated equipment information, standard equipment information, calibration personnel information, and specification information; automatically generate a calibration point sequence according to the equipment range and the set number of calibration points.

Further, the gas supply device is installed on the mobile device.

The calibration method based on the above-mentioned automatic in-situ calibration system includes the following steps:

S1. Purge and empty the transmitter calibration pipeline system;

S2. Open the pipeline of the differential pressure transmitter and/or for the calibration valve on the calibration interface in the pipeline of the differential pressure transmitter, close the other valves and enter the calibration state;

S3, connecting the gas supply device with the calibration interface;

S4. The measuring device collects the analog signal or digital signal output by the transmitter;

S5. The controller calculates the measurement error of the differential pressure transmitter or the pressure transmitter according to the received analog signal or digital signal.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

1. The present invention avoids the pressure transmitter or differential pressure transmitter process interface wear or body damage caused by repeated disassembly and transportation of the pressure transmitter or differential pressure transmitter in traditional metering.

2. The transmitter calibration pipeline system of the present invention can provide a batch calibration interface, which can be connected to multiple pressure transmitters and/or differential pressure transmitters at the same time, and can realize batch online calibration.

3. The calibration process of the present invention is fully automated, improving calibration efficiency.

Description of drawings

The drawings described here are used to provide a further understanding of the embodiments of the present invention, constitute a part of the application, and do not limit the embodiments of the present invention. In the attached picture:

Fig. 1 is the schematic diagram of in-situ calibration system of the present invention;

Fig. 2 is a structural diagram of the pressure calibration pipeline of the differential pressure transmitter of the present invention;

Fig. 3 is a structural diagram of the pressure calibration pipeline of the pressure transmitter of the present invention;

Fig. 4 is a schematic diagram of the channel switching switch of the present invention;

Fig. 5 is a schematic diagram of the connection between the analog output pressure and differential pressure transmitter of the present invention, the low-potential quick-plug terminal and the channel switching switch;

Fig. 6 is a schematic diagram of functional modules in the controller of the present invention.

Marks and corresponding parts names in the attached drawings:

1-transmitter calibration pipeline system; 2-gas supply device; 3-integrated cabinet; 4-controller; 31-low potential quick plug connector.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples and accompanying drawings. The schematic embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

Example 1:

As shown in Figures 1-6, an automatic in-situ calibration system for pressure and differential pressure transmitters includes a transmitter calibration pipeline system 1, a gas supply device 2, a measuring device and a controller 4;

The gas supply device 2 is used to provide gas for calibration to the transmitter calibration pipeline system 1; specifically: the gas supply device 2 includes a gas supply pipeline, a pressure controller and a gas booster pump; one end of the gas supply pipeline is connected to the gas source, and the other end is connected to the differential pressure transmitter pipeline and the calibration interface in the pressure transmitter pipeline; both the pressure controller and the gas booster pump are installed on the gas supply pipeline, and the pressure controller communicates with the controller 4, and the controller 4 controls the pressure controller to rise or fall to the required pressure point. The gas supply device 2 can realize 0-20MPa gas delivery. Preferably, the gas supply device 2 is installed on a mobile device, and the mobile device adopts any existing mobile equipment, such as a mobile trolley, and the gas supply device 2 can be transported to the on-site calibration site at will through the mobile device.

The calibration process of the transmitter calibration piping system 1 is:

Set the required pressure in the controller 4. After the gas source enters the pipeline, it will be continuously pressurized and filled to apply the pressure of the gas to the entire pipeline. The place where the valve is closed will not have this pressure, and the pipeline connected to the interface will have this pressure. There is a pressure-sensitive element in the high-pressure chamber, and this pressure-sensitive interface is generally called a "process interface", and then the pressure transmitter will convert the sensed pressure into a standardized signal of 4-20mA DC current signal output through the "electrical interface", and connect the cable out for measurement.

The transmitter calibration pipeline system 1 includes a differential pressure transmitter pipeline, a pressure transmitter pipeline, a differential pressure transmitter and a pressure transmitter. The differential pressure transmitter pipeline provides a calibration interface for the differential pressure transmitter to be connected to the gas supply device 2. The pressure transmitter pipeline provides a calibration interface for the pressure transmitter to be connected to the gas supply device 2. The transmitter calibration pipeline system 1 is located on a work site, a hall or a production line with a complex environment.

Specifically, the pipelines of the differential pressure transmitter and the pressure transmitter adopt the pipeline structures shown in Figure 2 and Figure 3 respectively:

Wherein, as shown in Figure 2, the differential pressure transmitter pipeline includes a first drain pipe and a second drain pipe, one end of the first drain pipe and the second drain pipe are respectively connected to the low-pressure chamber end and the high-pressure chamber end of the differential pressure transmitter, the first drain pipe and the second drain pipe are connected through a connecting pipe, and a balance valve is arranged on the connecting pipe; the first drain pipe is provided with a first shut-off valve and a first drain valve in order of distance from the differential pressure transmitter, and the second drain pipe is provided with a second shut-off valve in order of distance from the differential pressure transmitter and a second drain valve;

A first calibration pipe is provided on the first drain pipe between the first shut-off valve and the connecting pipe, and a first calibration valve is provided on the first calibration pipe;

A second calibration pipe is provided between the second cut-off valve and the connecting pipe on the second drain pipe, and a second calibration valve is provided on the second calibration pipe; the second calibration pipe is connected to the air supply device 2 .

The ends of the multiple second calibration tubes in the differential pressure transmitter pipeline away from the differential pressure transmitter are connected in series through the instrument tube, and an air source interface is installed at the end of the instrument tube, through which the gas source interface is connected to the gas supply device 2 .

Wherein, as shown in FIG. 3 , the pressure transmitter pipeline includes a third drain pipe, one end of the third drain pipe is connected to the pressure transmitter, and the third drain pipe is provided with a third shut-off valve and a third drain valve in sequence in order of being away from the pressure transmitter;

A third calibration pipe is provided on the third drain pipe between the third shut-off valve and the pressure transmitter, a third calibration valve is provided on the third calibration pipe, and the third calibration pipe is connected to the gas supply device 2 .

The end of the multiple third calibration tubes in the pressure transmitter pipeline away from the pressure transmitter is connected in series through the instrument tube, and an air source interface is installed at the end of the instrument tube, through which the gas source interface is connected to the gas supply device 2 .

The measuring device is used to collect the analog signal or digital signal output by the differential pressure transmitter or the pressure transmitter; the measuring device is installed in the integrated cabinet 3 .

Specifically, the measuring device includes an analog signal acquisition module and a control unit;

The analog signal acquisition module is used to collect the analog signal output by the pressure transmitter or differential pressure transmitter and transmits it to the control unit; specifically: the analog signal acquisition module includes a low-potential quick-plug connector 31, a transmitter switch and a digital multimeter; the low-potential quick-plug connector 31 is used to transmit the analog signal to the input channel of the transmitter switch, specifically: the "male head" of the low-potential quick-plug interface 31 is located outside the integrated cabinet 3, and the female head corresponds to each channel on the male head. The plug-in mode is connected to the female head, and the 8 pairs of channels of the female head located in the integrated cabinet 3 are connected to the 8 input channels of the transmitter switch; the digital multimeter is connected in series on the output channel of the transmitter switch, and the digital multimeter is used for measuring DC current signals.

Alternatively, the analog signal acquisition module further includes a standard resistor, which is connected in series to the output channel of the switch of the transmitter, and both ends of the standard resistor are connected to a digital multimeter for voltage measurement.

Among them, the transmitter switch includes the switch body, the power interface of the switch shell, the RS232 communication interface, the channel indicator light, 8 input channels, 1 output channel, the power supply system inside the switch, and the relay group.

The control unit is communicatively connected with the analog signal acquisition module, the output end of the pressure transmitter, and the output end of the differential pressure transmitter, and the control unit is used for collecting the pressure differential pressure transmitter and the digital signal output by the differential pressure transmitter.

As preferably: a power supply, a temperature and humidity sensor and a temperature and humidity adjustment device are also arranged in the integrated cabinet 3;

The power supply is used to supply power to the electrical equipment in the integrated cabinet 3;

Both the temperature and humidity sensor and the temperature and humidity adjustment device are electrically connected to the controller 4; the temperature and humidity sensor is used to collect the temperature and humidity in the integrated cabinet 3 in real time, and transmit the collected temperature and humidity signals to the controller 4, and the controller 4 controls the humidity adjustment device according to the received temperature and humidity to adjust the temperature and humidity in the integrated cabinet 3. The temperature and humidity adjustment device may be an air conditioner or the like.

The control unit transmits the collected digital signal or the received analog signal to the controller 4; the control unit integrates multiple communication physical interfaces including LAN, RS232, RS485, PA, and CAN, and is used to receive the output signal of the digital output pressure transmitter or digital output differential pressure transmitter and remotely control the digital multimeter, transmitter switch, temperature and humidity sensor, air conditioner and other equipment in the cabinet.

The controller 4 is connected in communication with the gas supply device 2 and the measuring device, and the controller 4 is used to control the gas supply pressure of the gas supply device 2; the controller 4 calculates the measurement error of the differential pressure transmitter or the pressure transmitter according to the received analog signal or digital signal.

Specifically: the controller 4 includes a verification calibration module and a data processing module;

The verification and calibration module is used to control the pressure controller in the gas supply device 2 to perform boosting or stepping down; it is used to control the switching execution channel of the transmitter switching switch in the measuring device, and is used to read the analog signal and digital signal of the control unit in the measuring device;

The data processing module is used to obtain the analog signal and digital signal read by the verification and calibration module, compare the read analog signal and digital signal with the nominal value, calculate the error, hysteresis, uncertainty, and generate the original record sheet.

As preferably: the controller 4 also includes a file management module, a device management module and a parameter setting module;

The file management module is used to store the original record table and calculation results generated by the data processing module.

The equipment management module is used to manage and maintain the information of the school equipment and standard equipment;

The parameter setting module is used to configure and save calibration environment information, calibrated equipment information, standard equipment information, calibration personnel information, and regulation specification information; automatically generate a calibration point sequence according to the equipment range and the number of calibration points set.

Example 2:

The calibration method based on the automatic in-situ calibration system described in embodiment 1 may further comprise the steps:

S1. Purging and emptying the transmitter calibration pipeline system 1: before calibration, empty the medium of the transmitter’s batch on-site calibration pipeline, open all valves, and purge the instrument tube to remove the residual medium in the tube;

S2. Open the pipeline of the differential pressure transmitter and/or for the calibration valve on the calibration interface in the pipeline of the differential pressure transmitter, close other valves and enter the calibration state:

For differential pressure transmitters, according to Figure 2, open the calibration valve 1 and calibration valve 2, and close the other valves to enter the calibration state; for pressure transmitters, according to Figure 3, close the shut-off valve and drain valve, open the calibration valve, and enter the calibration state;

S3, connecting the gas supply device 2 with the calibration interface;

S4. The measuring device collects the analog signal or digital signal output by the transmitter:

For the analog output pressure transmitter, connect its electrical output terminal to the male end of the low-potential quick-plug connector 31 outside the integrated cabinet 3 through the low-potential quick-plug connector 31. The male end of the low-potential quick-plug connector 31 is connected to the female head of the low-potential quick-plug connector 31 in the integrated cabinet 3. The 8 pairs of channels of the female head are connected to the input channels of the special switch for pressure transmitters. The output channels of the switch are connected to a digital multimeter to measure 4-20mA DC current signals. A standard resistor is connected in series on the output channel of the output channel, and a digital multimeter is connected to both ends of the resistor to measure the voltage; if the pressure transmitter to be calibrated is a digital output, the digital output pressure transmitter is connected to the control unit in the cabinet; that is, for the pressure transmitter to be calibrated is a digital output, the digital output pressure transmitter is connected to the corresponding digital switch through the low-potential quick-plug connector 31, and the output terminal of the switch is directly connected to the control unit instead of the digital multimeter;

S5. The controller 4 calculates the measurement error of the differential pressure transmitter or pressure transmitter according to the received analog signal or digital signal:

Set the information of the equipment to be calibrated, the information of the environment temperature and humidity, the reference documents, the information of the standard equipment used for calibration, the measurement range, and the number of measurement points on the controller 4, automatically generate the calibration sequence, and also perform secondary modification on the calibration sequence. For analog output pressure transmitters, controller 4 controls the pressure controller to rise or fall to the required pressure point. After the system judges that the pressure value is stable, it controls the switching switch to switch channels in turn. The digital multimeter sends the measured value to the control unit. The controller obtains the measured value through the control unit and then saves and displays it. For digital output pressure transmitters, controller 4 controls the pressure controller to rise or fall to the required pressure point. After the system judges that the pressure value is stable, it reads the digital signal output from the control unit and saves and displays it. , generating the original record.

The above-mentioned specific implementation manners further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above-mentioned descriptions are only specific implementation modes of the present invention, and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (14)

1. An automatic in-situ calibration system of a pressure and differential pressure transmitter is characterized by comprising a transmitter calibration pipeline system (1), a gas supply device (2), a measuring device and a controller (4);

the gas supply device (2) is used for supplying calibration gas to the transmitter calibration pipeline system (1);

the transmitter calibration pipeline system (1) comprises a differential pressure transmitter pipeline, a differential pressure transmitter and a pressure transmitter, wherein the differential pressure transmitter pipeline provides a calibration interface for the differential pressure transmitter to be connected with the air supply device (2), and the pressure transmitter pipeline provides a calibration interface for the pressure transmitter to be connected with the air supply device (2);

the measuring device is used for collecting analog quantity signals or digital quantity signals output by the differential pressure transmitter or the pressure transmitter;

the controller (4) is in communication connection with the air supply device (2) and the measuring device, and the controller (4) is used for controlling the air supply pressure of the air supply device (2); the controller (4) calculates a measurement error of the differential pressure transmitter or the pressure transmitter according to the received analog quantity signal or digital quantity signal.

2. An automatic in-situ calibration system for pressure and differential pressure transmitters as claimed in claim 1, wherein said gas supply means (2) comprises a gas supply line, a pressure controller and a gas booster pump;

one end of the air supply pipeline is connected with an air source, and the other end of the air supply pipeline is connected with the differential pressure transmitter pipeline and a calibration interface in the pressure transmitter pipeline;

the pressure controller and the gas booster pump are both arranged on the gas supply pipeline, the pressure controller is in communication connection with the controller (4), and the controller (4) controls the pressure controller to rise or fall to a required pressure point.

3. The automatic in-situ calibration system of a pressure and differential pressure transmitter according to claim 1, wherein the differential pressure transmitter pipeline comprises a first drain pipe and a second drain pipe, one ends of the first drain pipe and the second drain pipe are respectively connected with a low-pressure chamber end and a high-pressure chamber end of the differential pressure transmitter, the first drain pipe and the second drain pipe are connected through a connecting pipe, and a balance valve is arranged on the connecting pipe; the first drain pipe is sequentially provided with a first stop valve and a first drain valve in sequence far from the differential pressure transmitter, and the second drain pipe is sequentially provided with a second stop valve and a second drain valve in sequence far from the differential pressure transmitter;

a first calibration pipe is arranged between the first stop valve and the connecting pipe on the first drain pipe, and a first calibration valve is arranged on the first calibration pipe;

a second calibration pipe is arranged between the second stop valve and the connecting pipe on the second drain pipe, and a second calibration valve is arranged on the second calibration pipe; the second calibration pipe is connected with the air supply device (2).

4. The automatic in-situ calibration system of a pressure and differential pressure transmitter according to claim 1, wherein the pressure transmitter pipeline comprises a third drain pipe, one end of the third drain pipe is connected with the pressure transmitter, and a third stop valve and a third drain valve are sequentially arranged on the third drain pipe in a sequence far away from the pressure transmitter;

and a third calibration pipe is arranged between the third stop valve and the pressure transmitter on the third drain pipe, the third calibration pipe is provided with a third calibration valve, and the third calibration pipe is connected with the air supply device (2).

5. The automatic in-situ calibration system of a pressure and differential pressure transmitter according to claim 1, wherein the measuring device comprises an analog signal acquisition module and a control unit;

the analog quantity signal acquisition module is used for acquiring analog quantity signals output by the pressure transmitter or the differential pressure transmitter and transmitting the analog quantity signals to the control unit;

the control unit is in communication connection with the analog quantity signal acquisition module, the output end of the pressure transmitter and the output end of the differential pressure transmitter, and is used for acquiring digital quantity signals output by the pressure differential pressure transmitter and the differential pressure transmitter;

the control unit transmits the acquired digital quantity signal or the received analog quantity signal to the controller (4).

6. The automatic in-situ calibration system of a pressure, differential pressure transmitter of claim 5, wherein said analog signal acquisition module comprises a low potential quick connector (31), a transmitter change-over switch, and a digital multimeter;

the low-potential quick connector (31) is used for transmitting analog quantity signals to an input channel of a transmitter change-over switch; the digital multimeter is connected in series on an output channel of the transmitter change-over switch and is used for measuring direct current signals.

7. The automatic in-situ calibration system of a pressure and differential pressure transmitter of claim 6, wherein the analog signal acquisition module further comprises a standard resistor, the standard resistor is connected in series with an output channel of a transmitter change-over switch, and two ends of the standard resistor are connected with a digital multimeter for voltage measurement.

8. An automatic in-situ calibration system for pressure, differential pressure transmitters as claimed in claim 1, wherein said measuring means is mounted in an integrated cabinet (3).

9. The automatic in-situ calibration system of the pressure and differential pressure transmitter according to claim 8, wherein a power supply, a temperature and humidity sensor and a temperature and humidity regulating device are further arranged in the integrated cabinet (3);

the power supply is used for supplying power to electric equipment in the integrated cabinet (3);

the temperature and humidity sensor and the temperature and humidity regulating device are electrically connected with the controller (4); the temperature and humidity sensor is used for collecting the temperature and the humidity in the integrated cabinet (3) in real time and transmitting collected temperature and humidity signals to the controller (4), and the controller (4) controls the humidity adjusting device to adjust the temperature and the humidity in the integrated cabinet (3) according to the received temperature and the received humidity.

10. The automatic in-situ calibration system of a pressure, differential pressure transmitter of claim 1, wherein the controller (4) comprises a verification calibration module and a data processing module;

the verification calibration module is used for controlling a pressure controller in the air supply device (2) to perform boosting or depressurization; the execution channel is used for controlling a transmitter change-over switch in the change-over measuring device and is used for reading an analog quantity signal and a digital quantity signal of a control unit in the measuring device;

the data processing module is used for acquiring the analog quantity signal and the digital quantity signal read by the verification and calibration module, comparing the read analog quantity signal and digital quantity signal with a nominal value, calculating error, return difference and uncertainty, and generating an original record table.

11. The automatic in-situ calibration system of a pressure, differential pressure transmitter of claim 10, wherein said controller (4) further comprises a file management module;

the file management module is used for storing the original record table and the calculation result generated by the data processing module.

12. The automatic in-situ calibration system of a pressure, differential pressure transmitter of claim 10, wherein said controller (4) further comprises an equipment management module and a parameter setting module;

the device management module is used for managing and maintaining the information of the calibrated device and the standard device;

the parameter setting module is used for configuring and storing calibration environment information, calibrated equipment information, standard equipment information, calibrator information and rule specification information; and automatically generating a calibration point sequence according to the equipment range and the set calibration point number.

13. An automatic in-situ calibration system for pressure, differential pressure transmitters as claimed in any one of claims 1-12, wherein said gas supply means (2) is mounted on a mobile device.

14. Calibration method based on an automatic in-situ calibration system according to any of claims 1-13, comprising the steps of:

s1, carrying out purging and evacuating treatment on a transmitter calibration pipeline system (1);

s2, opening a differential pressure transmitter pipeline and/or for a calibration valve on a calibration interface in the differential pressure transmitter pipeline, closing other valves, and entering a calibration state;

s3, communicating the air supply device (2) with the calibration interface;

s4, the measuring device collects analog quantity signals or digital quantity signals output by the transmitter;

s5, the controller (4) calculates the measurement error of the differential pressure transmitter or the pressure transmitter according to the received analog quantity signal or digital quantity signal.