Actuating mechanism fault diagnosis circuit and control method thereof

Abstract

The invention provides an actuating mechanism fault diagnosis circuit and a control method thereof.The circuit comprises a control module and a fault monitoring module, the control module detects the working state of an actuating mechanism and generates a first diagnosis signal based on the working state of the actuating mechanism and the working state of the control module, and the fault monitoring module is connected with the control module and sends the first diagnosis signal to the control module; when the execution mechanism or the control module is abnormal, the fault signal can be output, the second diagnosis signal can be generated according to the execution state of the relay and fed back to the control module, closed-loop feedback is carried out when the execution mechanism breaks down, and the fault monitoring accuracy of the execution mechanism is improved. According to the diagnosis circuit provided by the invention, when the execution mechanism has a fault, is powered off, and the control module crashes or works abnormally, the relay can correctly output a fault information prompt, and the working state of the relay is monitored, so that closed-loop feedback is formed, the accuracy of fault monitoring is improved, and the false alarm frequency is reduced.

Description

Technical Field

[0001] The invention relates to the field of actuator fault monitoring, and in particular to an actuator fault diagnosis circuit and a control method thereof. Background Art

[0002] With the development of industry, it is crucial to monitor the operation of the actuator itself, so that when the actuator fails, corresponding measures can be taken quickly to the actuator to reduce the impact on production and life. In the relevant technology, the fault output scheme of the actuator is generally that when the actuator is powered on and working normally, the relay is controlled to remain in the on state through the input and output ports of the microcontroller unit (MCU). When the actuator fails or loses power, the MCU operates the input and output ports to control the disconnection state of the relay. However, the MCU of this scheme does not detect the output state of the relay, which is an open-loop control. When the MCU is not working properly, the input and output ports of the MCU may control the relay to output the on state (normal state of the actuator), which causes the staff to mistakenly believe that the actuator is working normally. This scheme cannot monitor the fault of the relay itself. If the relay fails and is always in the on state, there is also the possibility of misunderstanding the staff.

[0003] Therefore, how to provide a closed-loop fault diagnosis solution for monitoring the actuator is a technical problem that urgently needs to be solved. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, the present invention provides a technical solution of an actuator fault diagnosis circuit to solve at least one of the above-mentioned technical problems.

[0005] In order to achieve the above-mentioned purpose and other related purposes, the technical solution provided by this application is as follows.

[0006] According to a first aspect of an embodiment of the present application, there is provided an actuator fault diagnosis circuit, comprising:

[0007] A control module, used for collecting the working state of the actuator and generating a first diagnostic signal according to the working state and the working state of the control module;

[0008] A fault monitoring module receives the first diagnostic signal. If an abnormality occurs in the actuator or the control module, the fault monitoring module controls the relay in the fault monitoring module to output a fault signal based on the first diagnostic signal, and generates a second diagnostic signal according to the execution status of the relay, and feeds it back to the control module to monitor whether the device function of the relay is normal.

[0009] In one embodiment of the present invention, the fault monitoring module includes a fault output unit and a relay feedback unit. The fault output unit is connected to the first diagnostic signal. If an abnormality occurs in the actuator or the control module, the coil of the relay is controlled to be de-energized according to the first diagnostic signal, so that the normally open contact of the relay is disconnected and the fault signal is output to the outside. The relay feedback unit is connected to the fault output unit, generates a second diagnostic signal according to the execution status of the relay, and feeds the second diagnostic signal back to the control module.

[0010] In one embodiment of the present invention, the fault output unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first diode, a second diode, a third diode, a first polarity capacitor, a second polarity capacitor, a coil of the relay, an NPN transistor and a first photocoupler; the positive electrode of the first power supply is connected to the first input end of the first photocoupler through the first resistor, the first output end of the first photocoupler is connected to the positive electrode of the second power supply, the second output end of the first photocoupler is connected to the positive electrode of the first polarity capacitor, the second output end of the first photocoupler is connected to the first end of the second resistor, the second end of the second resistor is connected to the anode of the first diode, the second end of the second resistor is also connected to the negative electrode of the second power supply, and the first The cathode of a diode is connected to the cathode of the first polarity capacitor and the anode of the second diode, the cathode of the second diode is connected to the positive electrode of the second polarity capacitor via the third resistor, the positive electrode of the second polarity capacitor is also connected to the first end of the fourth resistor, the negative electrode of the second polarity capacitor is connected to the negative electrode of the second power supply, the second end of the fourth resistor is connected to the base of the NPN transistor, the positive electrode of the second power supply is connected to the collector of the NPN transistor via the coil of the relay, the emitter of the NPN transistor is connected to the negative electrode of the second power supply, the anode of the third diode is connected to the collector of the NPN transistor, and the cathode of the third diode is connected to the positive electrode of the second power supply; wherein, the second input end of the first photocoupler is connected to the first diagnostic signal.

[0011] In one embodiment of the present invention, the relay feedback unit includes a fifth resistor, a sixth resistor, a second photocoupler and a normally open contact of the relay, the positive electrode of the second power supply is connected to the first input end of the second photocoupler via the fifth resistor, the first end of the normally open contact of the relay is connected to the negative electrode of the second power supply, the second end of the normally open contact of the relay is connected to the second input end of the second photocoupler, the positive electrode of the first power supply is connected to the first output end of the second photocoupler via the sixth resistor, and the second output end of the second photocoupler is grounded, wherein the first output end of the second photocoupler outputs the second diagnostic signal.

[0012] In one embodiment of the present invention, the photoelectric coupler includes a light emitting diode and a transistor, the anode of the light emitting diode is the first input terminal of the photoelectric coupler, the cathode of the light emitting diode is the second input terminal of the photoelectric coupler, the collector of the transistor is the first output terminal of the photoelectric coupler, and the emitter of the transistor is the second output terminal of the photoelectric coupler.

[0013] In one embodiment of the present invention, the circuit further includes a display module, the display module is connected to the control module, the control module determines whether the relay is faulty based on the fault signal and the second diagnostic signal, and the display module displays the device function of the relay.

[0014] In one embodiment of the present invention, the circuit also includes a relay monitoring module, which is connected to the second diagnostic signal and the display module. If the control module is abnormal, the relay monitoring module determines whether the relay is faulty based on the second diagnostic signal and the execution status of the relay, so that the display module displays the device function of the relay to the outside.

[0015] According to a second aspect of an embodiment of the present application, a control method for an actuator fault diagnosis circuit is provided, which is applied to the actuator fault diagnosis circuit as described above, comprising:

[0016] Acquiring the working state of the actuator, and generating the first diagnostic signal according to the working state and the working state of the control module;

[0017] If the actuator or the control module is abnormal, the relay is controlled to generate the fault signal based on the first diagnostic signal, and the second diagnostic signal is generated according to the execution state of the relay.

[0018] In one embodiment of the present invention, the first diagnostic signal is generated according to the working state and the working state of the control module, including: if the actuator and the control module are both normal, the control module generates the first diagnostic signal with a preset duty cycle; if the actuator or the control module is abnormal, the control module generates the first diagnostic signal with a fixed level.

[0019] In one embodiment of the present invention, if the actuator or the control module is abnormal, the relay is controlled to generate the fault signal based on the first diagnostic signal, including: if the actuator or the control module is abnormal, the coil of the relay is controlled to be de-energized based on the first diagnostic signal of a fixed level, the normally open contact of the relay is disconnected, and the fault signal is output to the outside.

[0020] The present application provides an actuator fault diagnosis circuit and a control method thereof, the circuit includes a control module and a fault monitoring module, the control module detects the working state of the actuator, and generates a first diagnostic signal based on the working state of the actuator and the working state of the control module, the fault monitoring module is connected to the control module, not only can it output a fault signal to the outside when an abnormality occurs in the actuator or the control module, but it can also generate a second diagnostic signal according to the execution state of the relay, and feed it back to the control module, so as to realize closed-loop feedback when an actuator fault occurs, so as to improve the accuracy of the actuator fault monitoring. The diagnostic circuit provided by the present application can correctly output fault information prompts when the actuator fails, the power is cut off, the control module freezes or does not work properly, and also monitors the working state of the relay, thereby forming a closed-loop feedback, improving the accuracy of fault monitoring and reducing the number of false alarms.

[0021] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0023] Figure 1 is a block diagram of an actuator fault diagnosis circuit shown in an exemplary embodiment of the present invention;

[0024] Figure 2 is a specific circuit structure of a fault monitoring module shown in an exemplary embodiment of the present invention;

[0025] Figure 3 is a block diagram showing an actuator fault diagnosis circuit including a display module according to an exemplary embodiment of the present invention;

[0026] Figure 4 It is a block diagram showing an actuator fault diagnosis circuit including a relay monitoring module according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following will describe the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention.

[0028] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0029] In the following description, numerous details are discussed to provide a more thorough explanation of the embodiments of the present invention. However, it is obvious to those skilled in the art that the embodiments of the present invention can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present invention difficult to understand.

[0030] With the development of industry, it is crucial to monitor the operation of the actuator itself, so that when the actuator fails, corresponding measures can be taken quickly to the actuator to reduce the impact on production and life. In the relevant technology, the fault output scheme of the actuator is generally: when the actuator is powered on and working normally, the relay is controlled to remain in the on state through the input and output ports of the microcontroller unit (MCU). When the actuator fails or loses power, the relay is controlled to be disconnected through the input and output ports of the MCU. However, the MCU of this scheme does not detect the output state of the relay, which is an open-loop control. When the MCU is not working properly, the input and output ports of the MCU may control the relay to output the on state (normal state of the actuator), which may cause the staff to mistakenly believe that the actuator is working normally. This scheme cannot monitor the fault of the relay itself; if the relay fails and is always in the on state, there is also the possibility of misunderstanding the staff.

[0031] To solve the above problems, Figure 1 As shown, the present application provides an actuator fault diagnosis circuit, comprising:

[0032] A control module, used for collecting the working state of the actuator and generating a first diagnostic signal P1 according to the working state and the working state of the control module;

[0033] The fault monitoring module receives the first diagnostic signal P1. If an abnormality occurs in the actuator or the control module, the relay in the fault monitoring module is controlled to output a fault signal F0 based on the first diagnostic signal P1, and a second diagnostic signal P2 is generated according to the execution status of the relay, and fed back to the control module to monitor whether the device function of the relay is normal.

[0034] In detail, the fault monitoring module includes a fault output unit and a relay feedback unit. The fault output unit is connected to the first diagnostic signal P1. If an abnormality occurs in the actuator or the control module, the coil KM of the relay is controlled to be de-energized according to the first diagnostic signal P1, so that the normally open contact A1 of the relay is disconnected, and the fault signal F0 is output to the outside; the relay feedback unit is connected to the fault output unit, generates a second diagnostic signal P2 according to the execution status of the relay, and feeds the second diagnostic signal P2 back to the control module.

[0035] In more detail, Figure 2 As shown, the fault output unit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first diode D1, a second diode D2, a third diode D3, a first polarity capacitor C1, a second polarity capacitor C2, a coil KM of a relay, an NPN transistor Q1 and a first photocoupler U1; the positive electrode VCC+ of the first power supply is connected to the first input end of the first photocoupler U1 after passing through the first resistor R1, the first output end of the first photocoupler U1 is connected to the positive electrode VHH+ of the second power supply, the second output end of the first photocoupler U1 is connected to the positive electrode of the first polarity capacitor C1, the second output end of the first photocoupler U1 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the anode of the first diode D1, and the second end of the second resistor R2 is also connected to the negative electrode V HH-, the cathode of the first diode D1 is connected to the cathode of the first polarity capacitor C1 and the anode of the second diode D2, the cathode of the second diode D2 is connected to the positive electrode of the second polarity capacitor C2 via the third resistor R3, the positive electrode of the second polarity capacitor C2 is also connected to the first end of the fourth resistor R4, the negative electrode of the second polarity capacitor C2 is connected to the negative electrode VHH- of the second power supply, the second end of the fourth resistor R4 is connected to the base of the NPN transistor Q1, the positive electrode VHH+ of the second power supply is connected to the collector of the NPN transistor Q1 via the coil KM of the relay, the emitter of the NPN transistor Q1 is connected to the negative electrode VHH- of the second power supply, the anode of the third diode D3 is connected to the collector of the NPN transistor Q1, and the cathode of the third diode D3 is connected to the positive electrode VHH+ of the second power supply; wherein, the second input end of the first photocoupler U1 is connected to the first diagnostic signal P1.

[0036] In more detail, Figure 2As shown, the relay feedback unit includes a fifth resistor R5, a sixth resistor R6, a second photocoupler U2 and a normally open contact A1 of the relay, the positive electrode VHH+ of the second power supply is connected to the first input terminal of the second photocoupler U2 via the fifth resistor R5, the first end of the normally open contact A1 of the relay is connected to the negative electrode VHH- of the second power supply, the second end of the normally open contact A1 of the relay is connected to the second input terminal of the second photocoupler U2, the positive electrode VCC+ of the first power supply is connected to the first output terminal of the second photocoupler U2 via the sixth resistor R6, and the second output terminal of the second photocoupler U2 is grounded, wherein the first output terminal of the second photocoupler U2 outputs a second diagnostic signal P2.

[0037] It should be emphasized that if Figure 2 As shown, the normally open contact A1 of the relay includes two double-pole double-throw switches, the first end of the first switch is connected to the negative pole VHH- of the second power supply, the second end of the first switch is connected to the second input end of the second photocoupler U2, the first end of the second switch is connected to the contact point JC_NC, the second end of the second switch is connected to the contact point JC_COM, and the contacts JC_NC and JC_COM are used to collect the fault signal F0 output by the relay; wherein, the contacts used to collect the fault signal F0 can also be connected to the two ends of the first switch, therefore, only one switch can be used.

[0038] It should be noted that the photoelectric coupler (U1, U2) includes a light-emitting diode and a transistor, the anode of the light-emitting diode is the first input terminal of the photoelectric coupler (U1, U2), the cathode of the light-emitting diode is the second input terminal of the photoelectric coupler (U1, U2), the collector of the transistor is the first output terminal of the photoelectric coupler (U1, U2), and the emitter of the transistor is the second output terminal of the photoelectric coupler (U1, U2).

[0039] In more detail, Figure 3 As shown, the circuit also includes a display module, which is connected to the control module. The control module determines whether the relay is faulty according to the fault signal F0 and the second diagnostic signal P2, and the display module displays the device function of the relay.

[0040] In more detail, Figure 4 As shown, the circuit also includes a relay monitoring module, which is connected to the second diagnostic signal P2 and the display module. If the control module is abnormal, the relay monitoring module determines whether the relay is faulty based on the second diagnostic signal P2 and the execution status of the relay, so that the display module can display the device function of the relay to the outside. Due to the failure of the control module, the second diagnostic signal P2 and the fault signal F0 cannot be transmitted to the control module.

[0041] like Figures 1 to 4 As shown, the working principle of the actuator fault diagnosis circuit provided by this application is as follows:

[0042] like Figure 1 As shown, the control module detects the working state of the actuator and generates a first diagnostic signal P1 according to the working state of the actuator and the working state of the control module. If the actuator and the control module work normally, the control module generates a first diagnostic signal P1 with a frequency of 100HZ and a duty cycle of 50%. The first diagnostic signal P1 is a pulse signal. The pulse signal is sent to the fault monitoring module. Figure 2 , the first photocoupler U1 is turned on, thereby controlling the NPN transistor Q1 to be turned on, the coil KM of the relay is energized, the normally open contact A1 of the relay is closed, the second photocoupler U2 is turned on, and the second diagnostic signal P2 is at a low level. The control module collects the second diagnostic signal P2 and the execution status of the relay to determine whether the relay is normal.

[0043] Combination Figure 2 As shown, if the actuator or control module is abnormal, the first diagnostic signal P1 is high or low, and no pulse signal is generated. Because the first polarity capacitor C1 isolates the DC voltage, the NPN transistor Q1 is cut off, the coil KM of the relay is not energized, the normally open contact A1 of the relay is disconnected, and a fault signal is output to the outside. The second photocoupler U2 is cut off, and the second diagnostic signal P2 is high.

[0044] like Figure 3 As shown, when the control module is normal, the control module determines whether the relay is normal according to the second diagnostic signal P2 and the fault signal F0. If the relay is abnormal, the display module displays the relay fault condition to the user, so that the staff can repair the faulty relay.

[0045] like Figure 4 As shown, if the control module is abnormal, the normally open contact A1 of the relay in the fault monitoring module is disconnected. Due to the abnormality of the control module, the second diagnostic signal P2 is collected through the relay monitoring module to determine whether the relay is faulty based on the second diagnostic signal P2 and the execution status of the relay, and the fault condition of the relay is displayed through the display module.

[0046] If the coil KM of the relay is energized, the normally open contact A1 of the relay is closed, and the second diagnostic signal P2 is at a low level, the control module or the relay monitoring module determines that the relay is normal; if the coil KM of the relay is energized, the normally open contact A1 of the relay is disconnected, and the second diagnostic signal P2 is at a high level, the control module or the relay monitoring module determines that the relay is faulty; if the coil KM of the relay is not energized, the normally open contact A1 of the relay is closed, and the second diagnostic signal P2 is at a low level, the control module or the relay monitoring module determines that the relay is faulty, and the relay fault is displayed as a warning on the display screen.

[0047] The present application also provides a control method for an actuator fault diagnosis circuit, which is applied to the actuator fault diagnosis circuit as described above, comprising:

[0048] Acquire the working state of the actuator, and generate a first diagnostic signal P1 according to the working state and the working state of the control module;

[0049] If the actuator or the control module is abnormal, the relay is controlled to generate a fault signal F0 based on the first diagnostic signal P1, and a second diagnostic signal P2 is generated according to the execution state of the relay.

[0050] In detail, the first diagnostic signal P1 is generated according to the working state and the working state of the control module, including: if the actuator and the control module are both normal, the control module generates the first diagnostic signal P1 with a preset duty cycle; if the actuator or the control module is abnormal, the control module generates the first diagnostic signal P1 with a fixed level. Specifically, the control module generates the first diagnostic signal based on the working state of the actuator and the control module. When the actuator and the control module are both working normally, the control module outputs the first diagnostic signal P1 with a frequency of 100HZ and a duty cycle of 50%; when at least one of the actuator or the control module is abnormal, the control module outputs the first diagnostic signal P1 with a fixed level, and at this time, the first diagnostic signal is a high level or a low level.

[0051] In more detail, if the actuator or control module is abnormal, the relay is controlled to generate a fault signal F0 based on the first diagnostic signal P1, including: if the actuator or control module is abnormal, the coil KM of the relay is controlled to be de-energized based on the first diagnostic signal P1 of a fixed level, the normally open contact A1 of the relay is disconnected, and the fault signal F0 is output externally. Specifically, if the actuator or control module is abnormal, the first diagnostic signal P1 is high level or low level, and no pulse signal is generated. Because the first polarity capacitor C1 isolates the DC voltage, the NPN transistor Q1 is cut off, the coil KM of the relay is not energized, the normally open contact A1 of the relay is disconnected, and the fault signal F0 is output externally.

[0052] The present application provides an actuator fault diagnosis circuit and a control method thereof, the circuit includes a control module, a fault monitoring module, a display module and a relay monitoring module, the control module monitors the working state of the actuator, and generates a first diagnostic signal based on the working state of the actuator and the working state of the control module, the fault monitoring module is connected to the control module, not only can it output a fault signal externally when an abnormality occurs in the actuator or the control module, but it can also generate a second diagnostic signal according to the execution state of the relay and feedback it to the control module, the display module externally displays the device function of the relay, and alarms in time when an abnormality occurs, and when the control module is abnormal, it can continue to monitor the machine function of the relay through the relay monitoring module to provide comprehensive protection, and perform closed-loop feedback when an actuator fault occurs, so as to improve the accuracy of the actuator fault monitoring. The diagnostic circuit provided by the present application, when the actuator fails, the power is off, the control module freezes or does not work properly, the relay can correctly output the fault information prompt, and also monitors the working state of the relay, thereby forming a closed-loop feedback, improving the accuracy of fault monitoring and reducing the number of false alarms.

[0053] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An actuator fault diagnosis circuit, characterized in that: include: A control module, used for collecting the working state of the actuator and generating a first diagnostic signal according to the working state and the working state of the control module; A fault monitoring module receives the first diagnostic signal. If an abnormality occurs in the actuator or the control module, the fault monitoring module controls the relay in the fault monitoring module to output a fault signal based on the first diagnostic signal, and generates a second diagnostic signal according to the execution status of the relay, and feeds it back to the control module to monitor whether the device function of the relay is normal.

2. The actuator fault diagnosis circuit according to claim 1, characterized in that: The fault monitoring module includes a fault output unit and a relay feedback unit. The fault output unit is connected to the first diagnostic signal. If an abnormality occurs in the actuator or the control module, the coil of the relay is controlled to be de-energized according to the first diagnostic signal, so that the normally open contact of the relay is disconnected and the fault signal is output to the outside. The relay feedback unit is connected to the fault output unit, generates a second diagnostic signal according to the execution status of the relay, and feeds the second diagnostic signal back to the control module.

3. The actuator fault diagnosis circuit according to claim 2, characterized in that: The fault output unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first diode, a second diode, a third diode, a first polarity capacitor, a second polarity capacitor, a coil of the relay, an NPN transistor and a first photocoupler; The positive electrode of the first power supply is connected to the first input terminal of the first photocoupler through the first resistor, the first output terminal of the first photocoupler is connected to the positive electrode of the second power supply, the second output terminal of the first photocoupler is connected to the positive electrode of the first polarity capacitor, the second output terminal of the first photocoupler is connected to the first terminal of the second resistor, the second terminal of the second resistor is connected to the anode of the first diode, the second terminal of the second resistor is also connected to the negative terminal of the second power supply, the cathode of the first diode is connected to the cathode of the first polarity capacitor and the anode of the second diode, the cathode of the second diode is connected to the positive electrode of the second polarity capacitor through the third resistor, the positive electrode of the second polarity capacitor is also connected to the first terminal of the fourth resistor, the negative electrode of the second polarity capacitor is connected to the negative electrode of the second power supply, the second terminal of the fourth resistor is connected to the base of the NPN transistor, the positive electrode of the second power supply is connected to the collector of the NPN transistor through the coil of the relay, the emitter of the NPN transistor is connected to the negative terminal of the second power supply, the anode of the third diode is connected to the collector of the NPN transistor, and the cathode of the third diode is connected to the positive electrode of the second power supply; Wherein, the second input terminal of the first photoelectric coupler is connected to the first diagnostic signal.

4. The actuator fault diagnosis circuit according to claim 3, characterized in that: The relay feedback unit includes a fifth resistor, a sixth resistor, a second photocoupler and a normally open contact of the relay, the positive electrode of the second power supply is connected to the first input end of the second photocoupler via the fifth resistor, the first end of the normally open contact of the relay is connected to the negative electrode of the second power supply, the second end of the normally open contact of the relay is connected to the second input end of the second photocoupler, the positive electrode of the first power supply is connected to the first output end of the second photocoupler via the sixth resistor, and the second output end of the second photocoupler is grounded, wherein the first output end of the second photocoupler outputs the second diagnostic signal.

5. The actuator fault diagnosis circuit according to claim 4, characterized in that: The photoelectric coupler includes a light emitting diode and a transistor, wherein the anode of the light emitting diode is the first input end of the photoelectric coupler, the cathode of the light emitting diode is the second input end of the photoelectric coupler, the collector of the transistor is the first output end of the photoelectric coupler, and the emitter of the transistor is the second output end of the photoelectric coupler.

6. The actuator fault diagnosis circuit according to claim 1, characterized in that: The circuit also includes a display module, which is connected to the control module. The control module determines whether the relay is faulty according to the fault signal and the second diagnostic signal, and the display module displays the device function of the relay.

7. The actuator fault diagnosis circuit according to claim 6, characterized in that: The circuit also includes a relay monitoring module, which is connected to the second diagnostic signal and the display module. If the control module is abnormal, the relay monitoring module determines whether the relay is faulty based on the second diagnostic signal and the execution status of the relay, so that the display module can display the device function of the relay to the outside.

8. A control method for an actuator fault diagnosis circuit as claimed in any one of claims 1 to 7, characterized in that: include: Acquiring the working state of the actuator, and generating the first diagnostic signal according to the working state and the working state of the control module; If the actuator or the control module is abnormal, the relay is controlled to generate the fault signal based on the first diagnostic signal, and the second diagnostic signal is generated according to the execution state of the relay.

9. The control method of the actuator fault diagnosis circuit according to claim 8, characterized in that: Generating the first diagnostic signal according to the working state and the working state of the control module includes: If the actuator and the control module are both normal, the control module generates the first diagnostic signal with a preset duty cycle; If the actuator or the control module is abnormal, the control module generates the first diagnosis signal with a fixed level.

10. The control method of the actuator fault diagnosis circuit according to claim 9, characterized in that: If the actuator or the control module is abnormal, controlling the relay to generate the fault signal based on the first diagnostic signal includes: If the actuator or the control module is abnormal, the coil of the relay is controlled to be de-energized based on the first diagnostic signal of a fixed level, the normally open contact of the relay is disconnected, and the fault signal is output externally.

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