Multipath insulation resistance measuring device

Abstract

The invention belongs to the technical field of resistance measurement, and particularly discloses a multi-channel insulation resistance measuring device which comprises a shell and a multi-channel acquisition circuit board, on the multi-channel acquisition circuit board, a single-chip microcomputer is in communication connection with an external upper computer through a communication module, the single-chip microcomputer is electrically connected with a relay control module and an AD conversion module, and the relay control module is electrically connected with the AD conversion module. The AD conversion module is electrically connected with the high-voltage sampling module and the multi-path measurement module respectively, and the power supply module supplies power to the modules; a power interface, a communication interface and a plurality of groups of wiring terminals are arranged on the shell, the multi-path measurement module is connected with a plurality of groups of external special test electrodes through the plurality of groups of wiring terminals, the multi-path measurement module, the plurality of groups of wiring terminals and the plurality of groups of special test electrodes are in one-to-one correspondence, and the power module is connected with an external power supply through the power interface. The communication module is connected with an external upper computer through a communication interface. The multi-channel insulation resistance measuring device can measure multi-channel insulation resistance at the same time and store measurement data, and the working efficiency is improved. The device and the method are suitable for measuring multi-path insulation resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of resistance measurement, in particular to a multi-channel insulation resistance measuring device. Background Art

[0002] Insulation resistance is the most basic insulation indicator of electrical equipment and electrical lines. Insulation rods are a safety tool used in power systems, which can effectively prevent operators from electric shock. In order to ensure safety and reliability, insulation resistance testing of insulation rods is required. The traditional insulation resistance measurement method is to contact the insulation rod to be tested with the internal electrode device of the portable insulation rod insulation resistance tester to detect the resistance value. Only the insulation resistance of a single section of the insulation rod can be tested at a time. For the measurement of the insulation resistance of multiple sections of the insulation rod, it is necessary to repeat the wiring and measurement operations many times, which has low work efficiency. In addition, the portable insulation rod insulation resistance tester can only display the current test value, cannot store data, and cannot be transferred to the computer to be saved in the form of a document, which is inconvenient for the management of subsequent insulation resistance tests of the insulation rods. Summary of the invention

[0003] The purpose of the present invention is to provide a multi-channel insulation resistance measuring device, which can measure the insulation resistance of multiple channels at the same time, store the measured data, and improve the working efficiency.

[0004] In order to achieve the above-mentioned purpose, the technical methods adopted by the present invention are as follows: A multi-channel insulation resistance measuring device comprises a shell, and a multi-channel acquisition circuit board installed inside the shell, wherein a relay control module, a single-chip microcomputer, a power module, a communication module, an AD conversion module, a high-voltage sampling module and a multi-channel measurement module are arranged on the multi-channel acquisition circuit board, the single-chip microcomputer is connected to an external host computer through the communication module, the single-chip microcomputer is electrically connected to the relay control module and the AD conversion module respectively, the AD conversion module is electrically connected to the high-voltage sampling module and the multi-channel measurement module respectively, and the power supply module supplies power to the relay control module, the single-chip microcomputer, the communication module, the AD conversion module, the high-voltage sampling module and the multi-channel measurement module; a power supply interface, a communication interface and a plurality of groups of wiring terminals are arranged on the shell, the multi-channel measurement module is connected to a plurality of groups of external special test electrodes through the plurality of groups of wiring terminals, the multi-channel measurement module, the plurality of groups of wiring terminals and the plurality of groups of special test electrodes correspond to each other one by one, the power supply module is connected to an external power supply through the power supply interface, and the communication module is connected to an external host computer through the communication interface.

[0005] As a limitation: the power supply module includes an AC / DC conversion element and an isolation element, the model of the AC / DC conversion element is LS15-23B05DR3, the model of the isolation element is A0509S-2WR2, the input pin of the AC / DC conversion element is connected to an external power supply, the output pin of the AC / DC conversion element outputs a first voltage, the input pin of the isolation element inputs a second voltage, the output pin of the isolation element outputs a second voltage and a third voltage, a first capacitor is connected between the first voltage and ground, and a second capacitor and a third capacitor are respectively connected between the second voltage and the third voltage and ground.

[0006] As a limitation: the AD conversion module includes at least two AD converters and at least two reference voltage elements, the AD converters and the reference voltage elements correspond one to one, the clock pin, chip select pin, serial data input pin and serial data output pin of each AD converter are all connected to the single-chip microcomputer, the first crystal oscillator is connected between the main clock input pin and the main clock output pin of each AD converter, one end of the first crystal oscillator is connected to one end of the fifth capacitor, the other end of the first crystal oscillator is connected to one end of the sixth capacitor, and the other end of the fifth capacitor and the other end of the sixth capacitor are grounded; the reset pin of each AD converter is connected to one end of the second resistor, and the other end of the second resistor is connected to the first voltage; the voltage pin of each AD converter is connected to the first voltage, and a seventh capacitor is connected between the first voltage and the ground; the reference input pin of each AD converter is connected to the anode pin of a reference voltage element, the anode pin of the reference voltage element is connected to the first voltage through the third resistor, and the cathode pin of the reference voltage element is grounded; the reference input pins of all AD converters are connected, and the analog signal input ends of all AD converters are connected to the multi-channel measurement module, and the analog signal input end of one AD converter is also connected to the high-voltage sampling module.

[0007] As a limitation: the relay control module includes a first relay element, the common end of the first relay element is connected to the first voltage, one end of the coil of the first relay element is connected to the first voltage, the other end of the coil of the first relay element is connected to the collector of the first transistor, the emitter of the first transistor is grounded, the base of the first transistor is connected to one end of the fourth resistor, the other end of the fourth resistor is respectively connected to one end of the fifth resistor and the single-chip microcomputer, the current monitoring pin of the first relay element is connected to the single-chip microcomputer, and the reference voltage pin of the first relay element is connected to its adjustment pin.

[0008] As a limitation: the high-voltage sampling module includes a first operational amplifier, a voltage pin of the first operational amplifier is connected to the second voltage and the third voltage, the positive input pin of the first operational amplifier is respectively connected to one end of the ninth capacitor and one end of the eighth resistor, the other end of the ninth capacitor is grounded, the other end of the eighth resistor is respectively connected to one end of the ninth resistor and one end of the tenth resistor, the other end of the ninth resistor is grounded, the other end of the tenth resistor is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to one end of the twelfth resistor, the other end of the twelfth resistor is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to one end of the fourteenth resistor, and the other end of the fourteenth resistor is connected to the high voltage through the high-voltage terminal; the output pins of the first operational amplifier are respectively connected to one end of the first diode and one end of the seventh resistor, the other end of the first diode is respectively connected to one end of the eighth capacitor, one end of the sixth resistor and ground, and the other end of the sixth resistor is respectively connected to the other end of the seventh resistor, the other end of the eighth capacitor and the AD conversion module.

[0009] As a limitation: each group of wiring terminals includes a high-voltage terminal and a low-voltage terminal, the high-voltage terminal is connected to the test positive electrode, and the low-voltage terminal is connected to the test negative electrode; the measurement circuit of each channel in the multi-channel measurement module includes a second operational amplifier and a second relay element, the voltage pin of the second operational amplifier is connected to the second voltage and the third voltage, the positive input pin of the second operational amplifier is respectively connected to one end of the eleventh capacitor and one end of the seventeenth resistor, the other end of the eleventh capacitor is grounded, the other end of the seventeenth resistor is respectively connected to one end of the eighteenth resistor, the test positive electrode and one end of the inductor, the other end of the inductor is connected to one end of the twelfth capacitor, the other end of the twelfth capacitor is respectively connected to the test negative electrode and one end of the twenty-first resistor of the inductor, and the other end of the twenty-first resistor is connected to the high voltage; the other end of the eighteenth resistor is respectively connected to the One end of the nineteenth resistor is connected to the normally open end of the second relay element, the other end of the nineteenth resistor is respectively connected to the common end of the second relay element, the normally closed end of the second relay element and the ground, the voltage pin of the second relay element is connected to the first voltage and the third diode is connected between its negative pin and the positive pin, the negative pin of the second relay element is also connected to the collector of the second transistor, the emitter of the second transistor is grounded, the base of the second transistor is respectively connected to one end of the twentieth resistor and the single-chip microcomputer, and the other end of the twentieth resistor is grounded; the output pins of the second operational amplifier are respectively connected to one end of the second diode and one end of the sixteenth resistor, the other end of the second diode is respectively connected to one end of the tenth capacitor, one end of the fifteenth resistor and the ground, and the other end of the fifteenth resistor is respectively connected to the other end of the sixteenth resistor, the other end of the tenth capacitor and the AD conversion module.

[0010] As a limitation: the communication module includes an isolation transceiver and a communication serial port, the model of the isolation transceiver is TD501D485H, the communication serial port is an RS232 serial port, the differential signal input pin of the isolation transceiver is connected to the RS485 communication line, the signal sending pin, signal receiving pin and control pin of the isolation transceiver, and the signal sending pin and signal receiving pin of the RS232 serial port are all connected to the single-chip microcomputer, the voltage pin of the isolation transceiver is connected to the first voltage, the voltage pin of the RS232 serial port is respectively connected to the first voltage and one end of the fourth capacitor, the other end of the fourth capacitor is respectively connected to one end of the first resistor and the single-chip microcomputer, and the other end of the first resistor is grounded.

[0011] As a qualification: the microcontroller model is STC12C5A60S2 LQFP44.

[0012] Due to the adoption of the above scheme, the present invention has the following beneficial effects compared with the prior art: A multi-channel insulation resistance measuring device provided by the present invention can simultaneously measure multi-channel insulation resistance by arranging a relay control module, a single-chip computer, a power supply module, a communication module, an AD conversion module, a high-voltage sampling module and a multi-channel measurement module, thereby meeting the measurement of the insulation resistance of multiple sections or even a group of insulating rods, and improving the work efficiency of test personnel; the power supply module is powered by an external AC220V, which can meet the needs of long-term test work; the communication module communicates through the serial port RS485, which facilitates the subsequent storage and comparative analysis of the insulation resistance test data of the insulating rod by the upper computer, and facilitates the management of the insulation resistance test of the insulating rod.

[0013] The invention is suitable for measuring multi-channel insulation resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Figure 1 This is a structural block diagram of a multi-channel insulation resistance measuring device according to an embodiment of the present invention; Figure 2 A schematic diagram of a single chip microcomputer according to an embodiment of the present invention; Figure 3 is a circuit schematic diagram of a power module according to an embodiment of the present invention; Figure 4 The schematic diagram of the AD conversion module according to the embodiment of the present invention; Figure 5 The schematic diagram of the circuit of the relay control module according to the embodiment of the present invention; Figure 6 This is a circuit schematic diagram of a high voltage sampling module according to an embodiment of the present invention; Figure 7A circuit schematic diagram of a measurement circuit in a multi-channel measurement module according to an embodiment of the present invention; Figure 8 The figure is a circuit diagram of a communication module according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described below in conjunction with embodiments, but those skilled in the art should understand that the present invention is not limited to the following embodiments, and any improvements and equivalent changes made based on the specific embodiments of the present invention are within the scope of protection of the claims of the present invention.

[0017] Embodiment A multi-channel insulation resistance measuring device A multi-channel insulation resistance measuring device comprises a housing and a multi-channel acquisition circuit board installed inside the housing. The housing is installed on a bracket of a test system and is a waterproof insulation housing. Figure 1 As shown, the multi-channel acquisition circuit board is provided with a relay control module, a single chip microcomputer, a power supply module, a communication module, an AD conversion module, a high voltage sampling module and a multi-channel measurement module, such as Figure 2 As shown, the model of the single-chip microcomputer is STC12C5A60S2 LQFP44; the single-chip microcomputer is connected to the external host computer through the communication module, the single-chip microcomputer is electrically connected to the relay control module and the AD conversion module respectively, the AD conversion module is electrically connected to the high-voltage sampling module and the multi-channel measurement module respectively, and the power supply module supplies power to the relay control module, the single-chip microcomputer, the communication module, the AD conversion module, the high-voltage sampling module and the multi-channel measurement module; a DB9 interface and multiple groups of wiring terminals are provided on the shell, the multi-channel measurement module is connected to multiple groups of external special test electrodes through multiple groups of wiring terminals, the multi-channel measurement module, the multiple groups of wiring terminals and the multiple groups of special test electrodes correspond to each other one by one, the power supply module is connected to the external power supply through the DB9 interface, and the communication module is connected to the external host computer through the DB9 interface.

[0018] like Figure 3 As shown, the power supply module includes an AC / DC conversion element and an isolation element, the model of the AC / DC conversion element is LS15-23B05DR3, the model of the isolation element is A0509S-2WR2, the input pin of the AC / DC conversion element is connected to an external power supply, the output pin of the AC / DC conversion element outputs a first voltage of 5V, the input pin of the isolation element inputs a second voltage of 9V, the output pin of the isolation element outputs a second voltage of 9V and a third voltage of -9V, a first capacitor C1 is connected between the first voltage 5V and the ground, and a second capacitor C2 and a third capacitor C3 are respectively connected between the second voltage 9V and the third voltage -9V and the ground.

[0019] like Figure 4As shown, the AD conversion module includes at least two AD converters and at least two reference voltage elements, the AD converters and the reference voltage elements correspond to each other, the clock pin, chip select pin, serial data input pin and serial data output pin of each AD converter are connected to the single-chip microcomputer, the master clock input pin and the master clock output pin of each AD converter are connected to the first crystal oscillator Y1, one end of the first crystal oscillator Y1 is connected to one end of the fifth capacitor C5, the other end of the first crystal oscillator Y1 is connected to one end of the sixth capacitor C6, the other end of the fifth capacitor C5 and the other end of the sixth capacitor C6 are grounded; the reset pin of each AD converter is connected to the second One end of the resistor R2 and the other end of the second resistor R2 are connected to the first voltage 5V; the voltage pin of each AD converter is connected to the first voltage 5V, and a seventh capacitor C7 is connected between the first voltage 5V and the ground; the reference input pin of each AD converter is connected to the anode pin of a reference voltage element, the anode pin of the reference voltage element is connected to the first voltage 5V through the third resistor R3, and the cathode pin of the reference voltage element is grounded; the reference input pins of all AD converters are connected, and the analog signal input ends of all AD converters are connected to the multi-channel measurement module, and the analog signal input end of one AD converter is also connected to the high-voltage sampling module. This embodiment includes two AD converters and two reference voltage elements, the models of the two AD converters are AD7705 and AD7706, and the model of the reference voltage element is LM285-2.5.

[0020] like Figure 5 As shown, the relay control module includes a first relay element, the model of the first relay element is JQZ-32F5-Z, the common end of the first relay element is connected to the first voltage 5V, one end of the coil K0 of the first relay element is connected to the first voltage 5V, the other end of the coil K0 of the first relay element is connected to the collector of the first transistor Q1, the emitter of the first transistor Q1 is grounded, the base of the first transistor Q1 is connected to one end of the fourth resistor R4, the other end of the fourth resistor R4 is respectively connected to one end of the fifth resistor R5 and the single-chip microcomputer, the current monitoring pin of the first relay element is connected to the single-chip microcomputer, and the reference voltage pin of the first relay element is connected to its adjustment pin.

[0021] like Figure 6As shown, the high-voltage sampling module includes a first operational amplifier, the model of the first operational amplifier is OP07, the voltage pin of the first operational amplifier is connected to the second voltage 9V and the third voltage -9V, the positive input pin of the first operational amplifier is respectively connected to one end of the ninth capacitor C9 and one end of the eighth resistor R8, the other end of the ninth capacitor C9 is grounded, the other end of the eighth resistor R8 is respectively connected to one end of the ninth resistor R9 and one end of the tenth resistor R10, the other end of the ninth resistor R9 is grounded, the other end of the tenth resistor R10 is connected to one end of the eleventh resistor R11, and the other end of the eleventh resistor R11 is connected to the twelfth One end of the resistor R12 and the other end of the twelfth resistor R12 are connected to one end of the thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected to one end of the fourteenth resistor R14, and the other end of the fourteenth resistor R14 is connected to the high voltage HV through the HV terminal; the output pins of the first operational amplifier are respectively connected to one end of the first diode D1 and one end of the seventh resistor R7, the other end of the first diode D1 is respectively connected to one end of the eighth capacitor C8, one end of the sixth resistor R6 and ground, and the other end of the sixth resistor R6 is respectively connected to the other end of the seventh resistor R7, the other end of the eighth capacitor C8 and the AD conversion module.

[0022] Each group of terminals includes a high-voltage terminal and a low-voltage terminal, the high-voltage terminal is connected to the positive electrode of the test, and the low-voltage terminal is connected to the negative electrode of the test; each measurement circuit in the multi-channel measurement module includes a second operational amplifier and a second relay element, the model of the second operational amplifier is OP07, and the model of the second relay element is TQ2-5V. This embodiment is a four-channel measurement circuit, in which a group of terminals includes an L1 high-voltage terminal and an E1 low-voltage terminal, and the corresponding one-channel measurement circuit is as follows Figure 7As shown, the voltage pin of the second operational amplifier is connected to the second voltage 9V and the third voltage -9V, the positive input pin of the second operational amplifier is respectively connected to one end of the eleventh capacitor C11 and one end of the seventeenth resistor R17, the other end of the eleventh capacitor C11 is grounded, the other end of the seventeenth resistor R17 is respectively connected to one end of the eighteenth resistor R18, the test positive electrode L1 and one end of the inductor L, the other end of the inductor L is connected to one end of the twelfth capacitor C12, the other end of the twelfth capacitor C12 is respectively connected to the test negative electrode E1 and one end of the twenty-first resistor R21 of the inductor L, the other end of the twenty-first resistor R21 is connected to the high voltage HV; the other end of the eighteenth resistor R18 is respectively connected to one end of the nineteenth resistor R19 and the normally open end of the second relay element, the other end of the nineteenth resistor R19 is respectively connected to the second relay element The common end of the component, the normally closed end of the second relay element and the ground, the voltage pin of the second relay element is connected to the first voltage 5V and the third diode D3 is connected between its negative pin and the positive pin, the negative pin of the second relay element is also connected to the collector of the second transistor Q2, the emitter of the second transistor Q2 is grounded, the base of the second transistor Q2 is respectively connected to one end of the twentieth resistor R20 and the single-chip computer, and the other end of the twentieth resistor R20 is grounded; the output pins of the second operational amplifier are respectively connected to one end of the second diode D2 and one end of the sixteenth resistor R16, the other end of the second diode D2 is respectively connected to one end of the tenth capacitor C10, one end of the fifteenth resistor R15 and the ground, and the other end of the fifteenth resistor R15 is respectively connected to the other end of the sixteenth resistor R16, the other end of the tenth capacitor C10 and the AD conversion module.

[0023] like Figure 8 As shown, the communication module includes an isolation transceiver and a communication serial port. The model of the isolation transceiver is TD501D485H, the communication serial port is an RS232 serial port, the differential signal input pin of the isolation transceiver is connected to the RS485 communication line, the signal sending pin, signal receiving pin and control pin of the isolation transceiver, and the signal sending pin and signal receiving pin of the RS232 serial port are all connected to the single-chip microcomputer, the voltage pin of the isolation transceiver is connected to the first voltage 5V, the voltage pin of the RS232 serial port is respectively connected to the first voltage 5V and one end of the fourth capacitor C4, the other end of the fourth capacitor C4 is respectively connected to one end of the first resistor R1 and the single-chip microcomputer, and the other end of the first resistor R1 is grounded.

[0024] The use process of the multi-channel insulation resistance measuring device of this embodiment is as follows: first, the power supply line and the communication line are connected to the DB9 interface. After the power is turned on, the AC220V voltage is stepped down and stabilized by the power module to obtain a DC5V voltage, which is used to power the multi-channel insulation resistance measuring device. After sending a start test instruction to the single-chip microcomputer through the RS485 communication line, the relay control module controls the start of the high-voltage test. The high-voltage signal is sent to the single-chip microcomputer after being processed by the high-voltage sampling module and the AD converter, and a 2500V digital signal is obtained after conversion. After that, the multi-channel measurement module processes four-channel insulation resistance test signals at the same time, and a digital signal of the resistance value is obtained after being processed by the AD conversion module, and the digital signal is sent to the single-chip microcomputer. The single-chip microcomputer processes the high-voltage digital signal and the digital signals of the four-channel resistance and sends them to the external host computer through the communication module. After the host computer sends an end test instruction to the single-chip microcomputer through the communication module, the first relay element in the relay control module cuts off the high-voltage output to complete the test.

Claims

1. A multi-channel insulation resistance measuring device, characterized in that: The invention comprises a shell and a multi-channel acquisition circuit board installed inside the shell. The multi-channel acquisition circuit board is provided with a relay control module, a single-chip microcomputer, a power module, a communication module, an AD conversion module, a high-voltage sampling module and a multi-channel measurement module. The single-chip microcomputer is connected to an external host computer through the communication module. The single-chip microcomputer is electrically connected to the relay control module and the AD conversion module respectively. The AD conversion module is electrically connected to the high-voltage sampling module and the multi-channel measurement module respectively. The power supply module supplies power to the relay control module, the single-chip microcomputer, the communication module, the AD conversion module, the high-voltage sampling module and the multi-channel measurement module. The shell is provided with a power supply interface, a communication interface and a plurality of groups of wiring terminals. The multi-channel measurement module is connected to a plurality of groups of external special test electrodes through the plurality of groups of wiring terminals. The multi-channel measurement module, the plurality of groups of wiring terminals and the plurality of groups of special test electrodes correspond to each other one by one. The power supply module is connected to an external power supply through the power supply interface. The communication module is connected to an external host computer through the communication interface.

2. A multi-channel insulation resistance measuring device according to claim 1, characterized in that: The power module includes an AC / DC conversion element and an isolation element. The model of the AC / DC conversion element is LS15-23B05DR3, the model of the isolation element is A0509S-2WR2, the input pin of the AC / DC conversion element is connected to an external power supply, the output pin of the AC / DC conversion element outputs a first voltage, the input pin of the isolation element inputs a second voltage, the output pin of the isolation element outputs a second voltage and a third voltage, a first capacitor is connected between the first voltage and ground, and a second capacitor and a third capacitor are respectively connected between the second voltage and the third voltage and ground.

3. A multi-channel insulation resistance measuring device according to claim 2, characterized in that: The AD conversion module includes at least two AD converters and at least two reference voltage elements. The AD converters and the reference voltage elements correspond to each other one by one. The clock pin, chip select pin, serial data input pin and serial data output pin of each AD converter are all connected to the single-chip microcomputer. The first crystal oscillator is connected between the main clock input pin and the main clock output pin of each AD converter. One end of the first crystal oscillator is connected to one end of the fifth capacitor, the other end of the first crystal oscillator is connected to one end of the sixth capacitor, and the other end of the fifth capacitor and the other end of the sixth capacitor are grounded; the reset pin of each AD converter is connected to one end of the second resistor, and the other end of the second resistor is connected to the first voltage; the voltage pin of each AD converter is connected to the first voltage, and a seventh capacitor is connected between the first voltage and the ground; the reference input pin of each AD converter is connected to the anode pin of a reference voltage element, the anode pin of the reference voltage element is connected to the first voltage through a third resistor, and the cathode pin of the reference voltage element is grounded; the reference input pins of all AD converters are connected, and the analog signal input ends of all AD converters are connected to the multi-channel measurement module, and the analog signal input end of one AD converter is also connected to the high-voltage sampling module.

4. A multi-channel insulation resistance measuring device according to claim 3, characterized in that: The relay control module includes a first relay element, a common end of the first relay element is connected to a first voltage, one end of a coil of the first relay element is connected to the first voltage, the other end of the coil of the first relay element is connected to the collector of a first transistor, the emitter of the first transistor is grounded, the base of the first transistor is connected to one end of a fourth resistor, the other end of the fourth resistor is respectively connected to one end of a fifth resistor and a single-chip microcomputer, a current monitoring pin of the first relay element is connected to the single-chip microcomputer, and a reference voltage pin of the first relay element is connected to its adjustment pin.

5. A multi-channel insulation resistance measuring device according to claim 4, characterized in that: The high-voltage sampling module includes a first operational amplifier, a voltage pin of the first operational amplifier is connected to the second voltage and the third voltage, a positive input pin of the first operational amplifier is respectively connected to one end of a ninth capacitor and one end of an eighth resistor, the other end of the ninth capacitor is grounded, the other end of the eighth resistor is respectively connected to one end of the ninth resistor and one end of the tenth resistor, the other end of the ninth resistor is grounded, the other end of the tenth resistor is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to one end of the twelfth resistor, the other end of the twelfth resistor is connected to one end of the thirteenth resistor, the other end of the thirteenth resistor is connected to one end of the fourteenth resistor, and the other end of the fourteenth resistor is connected to the high voltage through the high-voltage terminal; the output pins of the first operational amplifier are respectively connected to one end of the first diode and one end of the seventh resistor, the other end of the first diode is respectively connected to one end of the eighth capacitor, one end of the sixth resistor and ground, and the other end of the sixth resistor is respectively connected to the other end of the seventh resistor, the other end of the eighth capacitor and the AD conversion module.

6. A multi-channel insulation resistance measuring device according to claim 5, characterized in that: Each group of terminals includes a high-voltage terminal and a low-voltage terminal, the high-voltage terminal is connected to the test positive electrode, and the low-voltage terminal is connected to the test negative electrode; the measurement circuit of each channel in the multi-channel measurement module includes a second operational amplifier and a second relay element, the voltage pin of the second operational amplifier is connected to the second voltage and the third voltage, the positive input pin of the second operational amplifier is respectively connected to one end of the eleventh capacitor and one end of the seventeenth resistor, the other end of the eleventh capacitor is grounded, the other end of the seventeenth resistor is respectively connected to one end of the eighteenth resistor, the test positive electrode and one end of the inductor, the other end of the inductor is connected to one end of the twelfth capacitor, the other end of the twelfth capacitor is respectively connected to the test negative electrode and one end of the twenty-first resistor of the inductor, and the other end of the twenty-first resistor is connected to the high voltage; the other end of the eighteenth resistor is respectively connected to the nineteenth resistor One end of the twentieth resistor and the normally-open end of the second relay element, the other end of the nineteenth resistor is respectively connected to the common end of the second relay element, the normally-closed end of the second relay element and the ground, the voltage pin of the second relay element is connected to the first voltage and the third diode is connected between its negative pin and the positive pin, the negative pin of the second relay element is also connected to the collector of the second transistor, the emitter of the second transistor is grounded, the base of the second transistor is respectively connected to one end of the twentieth resistor and the single-chip microcomputer, and the other end of the twentieth resistor is grounded; the output pins of the second operational amplifier are respectively connected to one end of the second diode and one end of the sixteenth resistor, the other end of the second diode is respectively connected to one end of the tenth capacitor, one end of the fifteenth resistor and the ground, and the other end of the fifteenth resistor is respectively connected to the other end of the sixteenth resistor, the other end of the tenth capacitor and the AD conversion module.

7. A multi-channel insulation resistance measuring device according to claim 6, characterized in that: The communication module includes an isolation transceiver and a communication serial port. The model of the isolation transceiver is TD501D485H, the communication serial port is an RS232 serial port, the differential signal input pin of the isolation transceiver is connected to the RS485 communication line, the signal sending pin, signal receiving pin and control pin of the isolation transceiver, and the signal sending pin and signal receiving pin of the RS232 serial port are all connected to the single-chip microcomputer, the voltage pin of the isolation transceiver is connected to the first voltage, the voltage pin of the RS232 serial port is respectively connected to the first voltage and one end of the fourth capacitor, the other end of the fourth capacitor is respectively connected to one end of the first resistor and the single-chip microcomputer, and the other end of the first resistor is grounded.

8. A multi-channel insulation resistance measuring device according to any one of claims 1 to 7, characterized in that: The model of the microcontroller is STC12C5A60S2 LQFP44.

Images