A pressure sensor detection device and detection system

Abstract

The present application relates to a detection device and a detection system for a pressure sensor, and relates to the technical field of detection equipment; it includes a cabinet, a power supply device and a pressure control device are arranged in the cabinet, the pressure control device is provided with at least one gas circuit output end, and the cabinet is also provided with at least one quick connector connected to the gas circuit output end, the quick connector is used to connect the pressure sensor connector; the cabinet is provided with a connection port corresponding to the quick connector, a plurality of interfaces are arranged on the connection port, and the pressure sensor is electrically connected to the pressure control device and the power supply device through the connection port, and the power supply device is used to provide a test voltage for the pressure sensor. The present application has the effect of efficiently realizing the detection of the pressure sensor.

Description

Technical Field

[0001] The present application relates to the technical field of detection equipment, and in particular to a detection equipment and a detection system for a pressure sensor. Background Art

[0002] In the prior art, when testing a digital pressure display gauge, since the mounting structure of the digital display gauge is a threaded connection, in order for the digital display gauge to detect air pressure, it is usually necessary to manually screw the digital display gauge to a test station. If different data needs to be tested, the digital display gauge needs to be replaced to a different test station for testing, resulting in low testing efficiency. Summary of the invention

[0003] In order to efficiently implement the detection of a pressure sensor, the present application provides a detection device and a detection system for a pressure sensor.

[0004] On the one hand, the present application provides a pressure sensor detection device that adopts the following technical solution:

[0005] A detection device for a pressure sensor comprises a cabinet, wherein a power supply device and a pressure control device are arranged in the cabinet, wherein the pressure control device is provided with at least one gas circuit output end, and the cabinet is also provided with at least one quick connector connected to the gas circuit output end, wherein the quick connector is used to connect a pressure sensor connector; the cabinet is provided with a connection port corresponding to the quick connector, wherein the connection port is provided with a plurality of interfaces, and the pressure sensor is electrically connected to the pressure control device and the power supply device through the connection port, wherein the power supply device is used to provide a test voltage for the pressure sensor.

[0006] By adopting the above technical solution, the connection port can be set to facilitate the connection between the pressure sensor and the power supply device and the pressure control device, so that the pressure sensor can be detected, and the speed of connecting the pressure sensor to the test equipment can be increased by setting a quick connector; on this basis, when multiple quick connectors are provided, multiple pressure sensors can be detected at the same time, further improving the detection efficiency.

[0007] Preferably, the quick connector includes an inner column and a sliding sleeve slidably connected to the outer side of the inner column, and a vent hole is opened on the inner column; a plurality of locking claws are movably provided at the end of the inner column away from the cabinet, and the plurality of locking claws are arranged along the circumference of the inner column, and a partial thread is provided on the inner part of the locking claws near the vent hole; when the sliding sleeve moves along its own sliding trajectory to the end close to the cabinet, the plurality of locking claws are retracted in the sliding sleeve, and the plurality of partial threads are spliced ​​to form an internal thread that matches the thread of the connecting end of the pressure sensor; when the sliding sleeve moves along its own sliding trajectory to the end away from the cabinet, the plurality of locking claws spread to the outside of the sliding sleeve.

[0008] By adopting the above technical solution, the thread matching and disassembly of the pressure sensor joint are achieved by moving the sliding sleeve, so as to improve the disassembly and assembly efficiency of the pressure sensor and the detection equipment.

[0009] Preferably, a sliding column is provided on the inner wall of the sliding sleeve, and a sliding groove slidably connected to the sliding column is provided on the outer wall of the inner column.

[0010] By adopting the above technical solution, the sliding sleeve can slide relative to the inner column through the sliding column and the sliding groove that are slidably connected.

[0011] Preferably, an elastic sealing ring is filled between the plurality of locking claws and the inner column, and the peripheral side of the locking claws close to the vent hole is set as an inclined surface, and the side of the elastic sealing ring close to the locking claws fits into the inclined surface.

[0012] By adopting the above technical solution, the air tightness can be improved by setting an elastic sealing ring, and the inclined surface design on the peripheral side of the locking claw enables the elastic sealing ring to fit more closely on the locking claw, further enhancing the sealing effect and reducing the possibility of leakage.

[0013] Preferably, the cabinet is also provided with a knob for adjusting the output air pressure of the pressure control device.

[0014] By adopting the above technical solution and setting a knob, the inspector can accurately adjust the output air pressure of the pressure control device according to actual needs.

[0015] Preferably, the power supply device is used to output high-voltage power or low-voltage power, and the cabinet is provided with a power switch button, a high-voltage power selection button for controlling the power supply device to output high-voltage power, and a low-voltage power selection button for controlling the power supply device to output low-voltage power.

[0016] By adopting the above technical solution, the inspector can simply and conveniently control the power supply device to output high voltage power or low voltage power by selecting different buttons according to actual needs, without having to replace the power supply device separately.

[0017] On the other hand, the present application provides a pressure sensor detection system that adopts the following technical solution:

[0018] Preferably, it includes an air pressure detection unit, a power-on control unit and a current / voltage signal testing unit, the air pressure detection unit is used to detect the pressure value received by the pressure sensor, the power-on control unit is used to control the voltage received by the pressure sensor, and the current / voltage signal testing unit is used to detect the output current value / voltage value of the pressure sensor.

[0019] By adopting the above technical solution, by setting up a work pressure detection unit, a power-on control unit, a current / voltage signal test unit and a communication detection unit, it is possible to detect multiple functions of the pressure sensor.

[0020] Preferably, the power supply device includes an AC power supply and a DC power supply, and the power-on control unit includes a conversion switch, a DC current acquisition module and an AC current acquisition module. The voltage output end of the AC power supply is electrically connected to the first input end of the conversion switch through a relay, and the voltage output end of the DC power supply is electrically connected to the second input end of the conversion switch; the first output end of the conversion switch is electrically connected to the input end of the AC current acquisition module, and the second input end of the conversion switch is electrically connected to the input end of the DC current acquisition module; the output end of the AC current acquisition module and the output end of the DC current acquisition module are both electrically connected to the power supply terminal 1 pin of the connection port, and the ground terminal 2 pin of the connection port is respectively electrically connected to the first ground terminal and the second ground terminal of the conversion switch.

[0021] By adopting the above technical solution, not only can the power supply device selectively provide high voltage power supply or low voltage power supply through the conversion switch, but also by setting up an AC current acquisition module and a DC current acquisition module, it can also detect power consumption by collecting AC current and DC current.

[0022] Preferably, the air pressure detection unit includes a relay group and at least one electric pneumatic ball valve, and the output end of the electric pneumatic ball valve is electrically connected to a digital display; the relay group includes at least one solenoid valve, and the control end of the solenoid valve is controlled and connected to a PLC, and the 4 pins of the connection port are electrically connected to the input end of the solenoid valve, and the output end of the solenoid valve is electrically connected to the air valve control end of the electric pneumatic ball valve.

[0023] By adopting the above technical solution, the PLC controls the opening and closing of the solenoid valve and the flow rate passing through the solenoid valve, thereby realizing the control of the air pressure value; and when there are multiple detection channels, the use of multiple independent solenoid valves can prevent the channels from being idle and causing air pressure line problems.

[0024] Preferably, the current / voltage signal testing unit includes a data acquisition card, which is provided with a jumper 1 port and a jumper 2 port, the jumper 1 port is electrically connected to the normally closed contact of the relay, the jumper 2 port is electrically connected to the common end of the relay, and the normally open contact of the relay is electrically connected to the signal input end of the PLC, the signal input end of the PLC is electrically connected to pin 3 of the connection port, and pin 3 of the connection port is electrically connected to AIO+ of the data acquisition card, AIO- of the data acquisition card is grounded, and AIO+ of the data acquisition card and AIO- of the data acquisition card are connected in series with a voltmeter.

[0025] By adopting the above technical solution, the PLC can realize accurate control of the relay state, that is, control the power-on and power-off process of the relay, and then determine the open or closed state of the relay. Through the switching function of the relay, the working mode of the data acquisition card can be flexibly controlled, so that the data acquisition card can collect current or voltage signals as needed.

[0026] In summary, the present application includes at least one of the following beneficial technical effects:

[0027] 1. The installation and removal process of the pressure sensor can be simplified by setting up a quick connector, which enables rapid deployment and convenient maintenance, thereby greatly improving the detection efficiency of the pressure sensor. In addition, the function of multi-channel detection can be realized by configuring multiple quick connectors, so that multiple pressure sensors can be tested in parallel, further accelerating the detection process and improving the overall detection efficiency.

[0028] 2. In order to comprehensively evaluate the performance of the pressure sensor under different working conditions, a power-on control unit and an air pressure detection unit are also provided to ensure that the test conditions can be accurately set, covering different power supply voltages and pressure value ranges. At the same time, the system is also equipped with a current / voltage signal test unit, which works in conjunction with the power-on control unit and the air pressure detection unit to achieve a comprehensive test of the multi-dimensional functions of the pressure sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of Example 1 of the present application;

[0030] Figure 2 It is a schematic diagram of the structure of the quick connector in Example 1 of the present application;

[0031] Figure 3is a schematic cross-sectional structure diagram of the quick connector in Example 1 of the present application;

[0032] Figure 4 It is a principle block diagram of Example 2 of the present application;

[0033] Figure 5 This is a circuit diagram of the current / voltage signal testing unit in Example 2 of the present application.

[0034] Attached figures: 100, pressure sensor connector; 1, cabinet body; 11, pulley assembly; 12, cabinet door; 13, handle; 2, quick connector; 21, inner column; 211, sliding groove; 22, sliding sleeve; 221, sliding column; 23, locking claw; 231, partial thread; 24, vent hole; 25, elastic sealing ring; 3, connection port; 4, operating button; 5, digital display; 6, display. DETAILED DESCRIPTION

[0035] The following is combined with Figure 1-5 This application is described in further detail.

[0036] Embodiment 1 of the present application discloses a detection device for a pressure sensor.

[0037] Reference Figure 1 A pressure sensor detection device includes a cabinet 1, and a pressure control device and a power supply device are arranged inside the cabinet 1. The cabinet 1 is provided with a plurality of quick connectors 2 for connecting the pressure sensor to be tested, and a connection port 3 is provided on the cabinet 1 corresponding to each quick connector 2, and the connection port 3 is provided with a plurality of ports, and the pressure sensor is electrically connected to the pressure control device and the power supply device through the connection port 3, so that the pressure value and the power-on state of the pressure sensor can be adjusted. The pressure control device is also provided with a plurality of gas output ends, and the plurality of gas output ends and the plurality of quick connectors 2 are connected one by one, respectively, so as to form a plurality of detection channels. By providing the quick connector 2, the installation speed of the pressure sensor can be increased, thereby improving the testing efficiency of the pressure sensor.

[0038] Reference Figure 1 The cabinet 1 is in the shape of a rectangular parallelepiped as a whole, and the quick connector 2 and the connection port 3 are both arranged on the upper surface of the cabinet 1. A pulley assembly 11 is arranged on the lower surface of the cabinet 1 to facilitate the movement of the mobile cabinet 1. Preferably, the pulley assembly 11 also has a locking structure for locking the pulley, so that the cabinet 1 can stay at a designated position to facilitate subsequent detection work. The cabinet 1 is also provided with a cabinet door 12 on the side adjacent to the upper surface and the lower surface, and a handle 13 is also provided on the cabinet door 12 to facilitate maintenance and inspection of the internal power supply device and pressure control device.

[0039] The cabinet 1 is also provided with four operating buttons 4, which are respectively set as a power switch button, a first power selection button, a second power selection button and a pressure control knob. The four operating buttons 4 are equidistantly arranged along the short dimension direction of the upper surface of the cabinet 1, and are arranged on the same side of the multiple quick connectors 2. Among them, the power switch button is used to turn the power supply on or off. The power supply device is used to output high-voltage power and low-voltage power. In this embodiment, the first power selection button is used to control the power supply device to output a 220V voltage, and the second power selection button is used to control the power supply device to output a 24V voltage. The pressure control knob is used to control the output of the pressure control device so as to adjust the pressure applied to the pressure sensor, thereby being able to more comprehensively test the performance of the pressure sensor.

[0040] In order to facilitate the inspection personnel to observe the inspection parameters and inspection results, a digital display 5 is also provided on the same side of the cabinet 1 as the quick connector 2. The input end of the digital display 5 is respectively connected to the output ends of multiple gas circuits, and is mainly used to display the current air pressure value in the gas circuit; and a selection button is also provided on the digital display 5, so that the air pressure value of different inspection channels can be selected and displayed by adjusting the selection button.

[0041] Preferably, the connection port 3 may also include a communication interface, and an external host computer is connected to the communication interface via a data cable, wherein the host computer may be set as a terminal device such as a mobile phone, a tablet computer or a personal computer. In this embodiment, a personal computer is mainly used as an example for explanation. The host computer is used to receive the detection data of the multi-channel pressure sensor, and save and record it. A display 6 is also provided on the same side of the cabinet 1 as the digital display 5. The display 6 is electrically connected to the host computer and is mainly used to display the test results of multiple channels received by the host computer and historical records and other information. Refer to Figure 1 and Figure 2 In this embodiment, five quick connectors 2 are provided, and the five quick connectors 2 are arranged along a straight line parallel to the length direction of the upper surface of the cabinet 1, and the five quick connectors 2 are equidistantly arranged near one of the length direction sides of the upper surface of the cabinet 1. In this embodiment, the quick connector 2 is made of stainless steel material as a whole, so that the quick connector 2 has high rigidity and corrosion resistance, so as to extend the service life. Figure 2 and Figure 3 The quick connector 2 includes an inner column 21 and a sliding sleeve 22 slidably arranged on the outer side of the inner column 21. The inner column 21 is cylindrical in shape as a whole, and a vent hole 24 is opened in the inner column 21 along its own axial direction. One end of the inner column 21 in the length direction is connected to the corresponding gas path output end through a connecting pipe. A plurality of locking claws are movably arranged at the other end of the inner column 21 in the length direction, and a plurality of locking claws 23 are equidistantly arranged along the circumference of the inner column 21. In this embodiment, six locking claws 23 are arranged, and a partial thread 231 is arranged on the inner side of the locking claw 23 near the vent hole 24.

[0042] By sliding the sliding sleeve 22, the quick connector 2 can have two working modes, which are respectively set to the connection completion mode and the waiting connection mode. In the connection completion mode, the sliding sleeve 22 moves to the end away from the cabinet 1, and the multiple locking claws 23 are retracted inward and arranged inside the sliding sleeve 22, and the ends of the multiple partial threads 231 are butted and form an internal thread for matching with the pressure sensor connector 100. In the waiting connection mode, the sliding sleeve 22 moves to the end close to the cabinet 1, and the multiple locking claws 23 are dispersed outward, so that the pressure sensor connector 100 can be removed from the quick connector 2.

[0043] An elastic sealing ring 25 is filled between the locking claws 23 and the inner column 21, so as to ensure the air pressure value on the pressure sensor. In addition, the end surface of the locking claw 23 close to the inner column 21 and the peripheral side close to the vent 24 is set as an inclined surface, and the inclined surface is inclined toward the outer peripheral side of the locking claw 23 away from the vent 24, and the side of the elastic sealing ring 25 close to the locking claw 23 is designed to fit the inclined surface, further improving the air tightness.

[0044] The sliding sleeve 22 is in the shape of a cylindrical sleeve as a whole, and sliding posts 221 are arranged on opposite sides of the inner wall of the sliding sleeve 22 along its own diameter direction, and the length direction of the sliding posts 221 is parallel to the length direction of the inner column 21. The inner column 21 is provided with a sliding groove corresponding to the sliding post 221 and slidably connected to the sliding post 221, so that the sliding sleeve 22 can slide along the length direction of the inner column 21.

[0045] The implementation principle of the pressure sensor detection device in Example 1 of the present application is as follows: by providing a quick connector 2, the pressure sensor can be installed and removed more conveniently and quickly, thereby improving the detection efficiency of the pressure sensor. In addition, by providing multiple channels, multiple pressure sensors can be detected simultaneously, thereby further improving the detection efficiency.

[0046] Embodiment 2 of the present application discloses a detection system for a pressure sensor.

[0047] Reference Figure 4 A pressure sensor detection system includes a power-on control unit and an air pressure detection unit, which are used to provide detection conditions for the pressure sensor. In addition, the present embodiment also includes multiple functional units for detecting the pressure sensor, and the multiple functional units are respectively configured as current / voltage signal test units and communication detection units. The output end of the host computer is connected to a PLC for controlling the above multiple units.

[0048] Reference Figure 4, the power supply device includes an AC power supply and a DC power supply. In this embodiment, the AC power supply is used to output an AC voltage of 220V, and the DC power supply is connected to the host computer for communication and is used to output a DC voltage of 24V, and the DC power supply. The power-on control unit includes a conversion switch, a DC current acquisition module and an AC current acquisition module. The voltage output end of the AC power supply is electrically connected to the first input end of the conversion switch through a relay, and the voltage output end of the DC power supply is electrically connected to the second input end of the conversion switch. The first output end of the conversion switch is set to an N-line connection end and is electrically connected to the input end of the AC current acquisition module, and the second input end of the conversion switch is electrically connected to the input end of the DC current acquisition module. The output end of the AC current acquisition module and the output end of the DC current acquisition module are both electrically connected to the power supply end 1 pin of the connection port, and the ground end 2 pins of the connection port are electrically connected to the first ground end and the second ground end of the conversion switch respectively. Through the conversion switch, the pressure sensor can be controlled to access AC or DC.

[0049] Furthermore, the AC current acquisition module and the DC current acquisition module can realize the power consumption detection function by acquiring current, and the RS485 Modbus protocol is adopted in this embodiment, so that the tests of each channel do not interfere with each other.

[0050] The air pressure detection unit includes a relay group and a plurality of electric pneumatic ball valves, and each detection channel corresponds to an electric pneumatic ball valve. The output ends of the electric pneumatic ball valves are electrically connected to the input ends of the digital display, so that the air pressure value of the current air circuit can be displayed through the digital display, and the air pressure value received by the digital display can also be communicated and output and fed back to the host computer, so that relevant information can be displayed on the display screen. The control end of the relay group is electrically connected to the output end of the PLC. The relay group is set to include a plurality of independent solenoid valves, and the 4 pins of the connection port are electrically connected to the input ends of the plurality of solenoid valves, and the output ends of the plurality of solenoid valves are electrically connected to the air valve control ends of the plurality of electric pneumatic ball valves. By using a plurality of independent solenoid valves, it is possible to prevent the idle channels from causing air pressure line problems.

[0051] Reference Figure 4 and Figure 5The current / voltage signal test unit includes a data acquisition card, which provides two working modes: current acquisition or voltage acquisition. The data acquisition card is provided with a jumper 1 port and a jumper 2 port, wherein the jumper 1 port is electrically connected to the normally closed contact of the relay, the jumper 2 port is electrically connected to the common end of the relay, and the normally open contact of the relay is electrically connected to the signal input end of the PLC. The signal input end of the PLC is electrically connected to the 3rd pin of the connection port, and the 3rd pin of the connection port is electrically connected to the AIO+ of the data acquisition card, the AIO- of the data acquisition card is grounded, and the AIO+ of the data acquisition card and the AIO- of the data acquisition card are connected in series with a voltmeter. The PLC can control the power on or off of the relay, thereby controlling the opening or closing of the relay, so that the data acquisition card can collect current or voltage. And when the relay needs to be tested, the common end of the relay is electrically connected to the power output end of the DC power supply to realize the relay test function, so that the level state before and after ventilation of the PLC can be read respectively by the upper computer software.

[0052] Reference Figure 4 ,The communication detection unit includes a serial port server, and pins 5 and 6 of the connection port realize communication connection with the host computer through the serial port server, so that information interaction between the host computer and the pressure sensor can be realized, and the detection structure can be obtained.

[0053] The implementation principle of the pressure sensor detection system of Example 2 of the present application is as follows: by setting a power-on control unit and an air pressure detection unit, the detection conditions for the pressure sensor are provided, and the test results under different power supply voltages and pressure values ​​are conveniently tested. In addition, by setting a power consumption test unit, a current / voltage signal test unit and a communication detection unit, the detection of multiple functions of the pressure sensor is realized, and the test results are uploaded to the host computer through the serial port server.

[0054] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A pressure sensor detection device, characterized in that: The invention comprises a cabinet (1), wherein a power supply device and a pressure control device are arranged in the cabinet (1), wherein the pressure control device is provided with at least one gas path output end, and the cabinet (1) is also provided with at least one quick connector (2) connected to the gas path output end, wherein the quick connector (2) is used to connect a pressure sensor connector (100); the cabinet (1) is provided with a connection port (3) corresponding to the quick connector (2), wherein the connection port (3) is provided with a plurality of interfaces, and the pressure sensor is electrically connected to the pressure sensor through the connection port (3). The quick connector (2) comprises an inner column (21) and a sliding sleeve (22) slidably connected to the outer side of the inner column (21), and a vent hole (24) is provided on the inner column (21); a plurality of locking claws (23) are movably provided at the end of the inner column (21) away from the cabinet (1), and the plurality of locking claws (23) are arranged along the circumference of the inner column (21), and the locking claws (23) are close to the inner column (21). The vent hole (24) is provided with a partial thread (231) inside; when the sliding sleeve (22) moves along its own sliding trajectory to an end close to the cabinet (1), the plurality of locking claws (23) are retracted inside the sliding sleeve (22), and the plurality of partial threads (231) are spliced ​​to form an internal thread that matches the thread of the connection end of the pressure sensor; when the sliding sleeve (22) moves along its own sliding trajectory to an end away from the cabinet (1), the plurality of locking claws (23) are moved toward the sliding sleeve (22). The outer side of the sleeve (22) is diffused; a sliding column (221) is provided on the inner wall of the sliding sleeve (22); a sliding groove (211) is provided on the outer wall of the inner column (21) and is slidably connected to the sliding column (221); an elastic sealing ring (25) is filled between the plurality of locking claws (23) and the inner column (21), and the peripheral side of the locking claws (23) close to the vent hole (24) is set as an inclined surface, and the side of the elastic sealing ring (25) close to the locking claws (23) is in contact with the inclined surface.

2. A pressure sensor detection device according to claim 1, characterized in that: The cabinet (1) is also provided with a knob for adjusting the output air pressure of the pressure control device.

3. A pressure sensor detection device according to claim 1, characterized in that: The power supply device is used to output high-voltage power or low-voltage power. The cabinet (1) is provided with a power switch button, a high-voltage power selection button for controlling the power supply device to output high-voltage power, and a low-voltage power selection button for controlling the power supply device to output low-voltage power.

4. A pressure sensor detection system, based on the detection device according to any one of claims 1 to 3, characterized in that: It includes an air pressure detection unit, a power-on control unit and a current / voltage signal testing unit. The air pressure detection unit is used to detect the pressure value received by the pressure sensor, the power-on control unit is used to control the voltage received by the pressure sensor, and the current / voltage signal testing unit is used to detect the output current value / voltage value of the pressure sensor.

5. A pressure sensor detection system according to claim 4, characterized in that: The power supply device includes an AC power supply and a DC power supply, and the power-on control unit includes a conversion switch, a DC current acquisition module and an AC current acquisition module. The voltage output end of the AC power supply is electrically connected to the first input end of the conversion switch through a relay, and the voltage output end of the DC power supply is electrically connected to the second input end of the conversion switch; the first output end of the conversion switch is electrically connected to the input end of the AC current acquisition module, and the second input end of the conversion switch is electrically connected to the input end of the DC current acquisition module; the output end of the AC current acquisition module and the output end of the DC current acquisition module are both electrically connected to the power supply terminal 1 pin of the connection port, and the ground terminal 2 pins of the connection port are respectively electrically connected to the first ground terminal and the second ground terminal of the conversion switch.

6. A pressure sensor detection system according to claim 4, characterized in that: The air pressure detection unit includes a relay group and at least one electric pneumatic ball valve, and the output end of the electric pneumatic ball valve is electrically connected to a digital display; the relay group includes at least one solenoid valve, and the control end of the solenoid valve is controllably connected to a PLC, the 4 pins of the connection port are electrically connected to the input end of the solenoid valve, and the output end of the solenoid valve is electrically connected to the air valve control end of the electric pneumatic ball valve.

7. A pressure sensor detection system according to claim 6, characterized in that: The current / voltage signal testing unit includes a data acquisition card, on which a jumper 1 port and a jumper 2 port are provided, the jumper 1 port is electrically connected to a normally closed contact of a relay, the jumper 2 port is electrically connected to a common end of the relay, and the normally open contact of the relay is electrically connected to a signal input end of the PLC, the DI port of the PLC is electrically connected to pin 3 of the connection port, and pin 3 of the connection port is electrically connected to AIO+ of the data acquisition card, AIO- of the data acquisition card is grounded, and AIO+ of the data acquisition card and AIO- of the data acquisition card are connected in series with a voltmeter.

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