Safety torque stop hardware circuit capable of self-monitoring and self-diagnosing

Abstract

The utility model belongs to the technical field of frequency converters, and particularly relates to a safe torque stop hardware circuit capable of self-monitoring and self-diagnosing, which comprises a channel CH1, a channel CH2, a digital signal processor, a buffer 1, a buffer 2, a buffer 3, a state feedback circuit, a driving circuit, a safe torque switch, a power supply VCC, a power supply BP and an IGBT (Insulated Gate Bipolar Translator), the channel CH1 comprises a C2, a C3, a C4, a C5, a C6, a C7, an R1, an R2, an R3, an R4, an R5, an R6, a voltage-regulator tube ZD1, an optocoupler PC1 and an optocoupler PC2, and the optocoupler PC1 comprises an optocoupler PC2. According to the invention, through close connection and multiple diagnosis of all links of safe torque turn-off, efficient real-time monitoring and feedback of safe torque turn-off are realized, compared with the prior art, under the condition that too many lines and cost are not increased, the overall reliability and safety are improved, and meanwhile, standards of EN ISO13849-1 PL = e and IEC 61508 SIL3 are met.

Description

TECHNICAL FIELD

[0001] The utility model relates to frequency converter technical field, concretely is a kind of safe torque stop hardware circuit of self-monitoring and diagnosis. BACKGROUND

[0002] The application scene of frequency converter is more and more in today's era, as small as household appliances around, as large as industrial production, traffic and so on.So the safety, reliability of the product is more and more important in customer's mind.

[0003] When fault shutdown maintenance, emergency stop or periodic maintenance and other operations, for the use of traditional frequency converter, the following two ways are mainly used to realize the shutdown of motor torque, to let it stop automatically: ① cut off the power supply of frequency converter, realize the torque output stop of frequency converter;② stop sending PWM drive signal through frequency converter software program, so that the motor stops working.

[0004] The existing motor torque shutdown mode has the following shortcomings: the first kind of way after power failure, there is a large energy storage capacitor in the frequency converter, from power failure to motor stop output torque needs a certain time, the duration of this time depends on the discharge time constant of power supply, cannot meet the requirements of safety function, and will affect the use of common power supply equipment;The second kind of way of stopping MCU output PWM drive signal by software may exist BUG cannot respond, in this case, motor torque cannot be reliably shut down, at this time, the safety of equipment and operating personnel is threatened.Therefore, a hardware circuit is needed to effectively and reliably cut off the motor torque under the premise of uninterrupted power supply, to prevent accidental start of motor causing personnel injury and equipment damage.

[0005] Safe torque off (STO) safety function is clearly specified in IEC61508 standard.Functional safety is divided into four levels in IEC61508 standard, and the highest level is SIL4, and the highest level in industrial control field is SIL3.Most of the same type of products on the market still belong to SIL2 level, and the utility model meets ENISO13849-1 PL=e and IEC 61508 SIL3 standard.Compared with SIL2, SIL3 places more emphasis on self-diagnosis and real-time monitoring of the entire system, and rapid feedback of the system to external devices, so as to reduce the failure rate of the product and improve safety and reliability.STO function that meets SIL3 is the inevitable trend of future development.

[0006] Therefore, a kind of safe torque stop hardware circuit of self-monitoring and diagnosis is proposed to solve the above problems. INVENTION CONTENTS

[0007] The utility model discloses a purpose lies in providing a kind of self-monitoring and diagnosing safe torque stop hardware circuit, to solve the problem presented in the above background art.

[0008] To achieve the above object, the utility model provides the following technical scheme: a kind of self-monitoring and diagnosing safe torque stop hardware circuit, including passage CH1, passage CH2, digital signal processor, buffer 1, buffer 2, buffer 3, state feedback circuit, drive circuit, safe torque shutdown, power supply VCC, power supply BP and IGBT, the passage CH1 includes C2, C3, C4, C5, C6, C7, R1, R2, R3, R4, R5, R6, stabilivolt ZD1, optocoupler PC1, optocoupler PC2;The passage CH2 includes C8, C9, C10, C11, C12, C13, R7, R8, R11, R10, R12, R13, R14, stabilivolt ZD2, optocoupler PC3, optocoupler PC4;

[0009] The state feedback circuit includes capacitor C14, R18, R17, triode Q1, optocoupler PC5;

[0010] The enablement of the buffer 1 is connected with the common point of resistance R5 and capacitor C5, the diagnostic signal input end, output end, PWM signal receiving end of the buffer 1 are connected with digital signal processor, the PWM signal output end of the buffer 1 is connected with the PWM signal input end of the buffer 2, the diagnostic signal output end of the buffer 1 is also connected with resistance R15, and the other end of the resistance R15 is connected with power supply VCC;

[0011] The enablement of the buffer 2 is connected with the common point of resistance R12 and capacitor C11, the diagnostic signal input end and output end of the buffer 2 are connected with digital signal processor, the diagnostic signal output end of the buffer 2 is also connected with R16, and the other end of the resistance R16 is connected with power supply VCC, the PWM signal output end of the buffer 1 is connected with the PWM signal input end of the buffer 2, the PWM signal output end of the buffer 2 is connected with drive circuit, the drive circuit of the buffer 2 is connected with IGBT, and the output end of the IGBT is connected with motor;

[0012] The enablement of the buffer 3 is connected with resistance R9, the other end of the resistance R9 is connected with power supply VCC, the output end of the buffer 3 is connected with the right end of R14 and digital signal processor, the left end of the R14 is connected with the 2 pin of optocoupler PC2, PC4, and the input end and enablement of the buffer 3 are also connected with digital signal processor.

[0013] Preferably, the C2, C3 and R2 are connected in parallel between the 1 pin of the optical coupler PC1 and the anode of the voltage stabilizing tube ZD1, the cathode of the voltage stabilizing tube ZD1 is connected to the 2 pin of the optical coupler PC1, and the lower end of the R2 is connected to the anode of the voltage stabilizing tube ZD1; the R4 is connected at one end to the lower end of the R2 and at the other end to the 4 pin of the optical coupler PC2; the C6 is connected in parallel to the 3, 4 pins of the optical coupler PC2; the R1 is connected at one end to the 4 pin of the optical coupler PC1 and at the other end to the power supply VCC; the R3 is connected at one end to the 4 pin of the optical coupler PC1 and at the other end to the capacitor C4; the C4 is connected at one end to the ground GND and at the other end to the R3; the common point of the R3 and C4 is connected to the digital signal processor; the R5 is connected at one end to the 4 pin of the optical coupler PC1 and at the other end to the C5; the C5 is connected at one end to the ground GND and at the other end to the R5; the common point of the R5 and C5 is connected to the digital signal processor; the R6 and C7 are connected in parallel to the 1, 2 pins of the optical coupler PC2.

[0014] Preferably, the C9, C10 and R8 are connected in parallel between the 1 pin of the optical coupler PC3 and the anode of the voltage stabilizing tube ZD2, the cathode of the voltage stabilizing tube ZD2 is connected to the 2 pin of the optical coupler PC3, and the lower end of the R8 is connected to the anode of the voltage stabilizing tube ZD2; the R11 is connected at one end to the lower end of the R8 and at the other end to the 4 pin of the optical coupler PC4; the C13 is connected in parallel to the 3, 4 pins of the optical coupler PC4; the R7 is connected at one end to the 4 pin of the optical coupler PC3 and at the other end to the power supply VCC; the R10 is connected at one end to the 4 pin of the optical coupler PC3 and at the other end to the C8; the C8 is connected at one end to the ground GND and at the other end to the R10; the common point of the R10 and C8 is connected to the digital signal processor; the R12 is connected at one end to the 4 pin of the optical coupler PC3 and at the other end to the C11; the C11 is connected at one end to the ground GND and at the other end to the R12; the common point of the R12 and C11 is connected to the digital signal processor; the R13 and C12 are connected in parallel to the 1, 2 pins of the optical coupler PC4; the 2 pin of the optical coupler PC2 and the optical coupler PC4 is connected to the R14; the other end of the R14 is connected to the buffer 3.

[0015] Preferably, the C14 is connected in parallel between the collector and the emitter of the triode Q1; the collector of the triode Q1 is connected to the 4 pin of the optical coupler PC5, the base is connected to the 3 pin of the optical coupler PC5, and the emitter is connected to the ground SD; the R18 is connected at one end to the base of the triode Q1 and at the other end to the ground SD; the 1 pin of the optical coupler PC5 is connected to the power supply BP, and the 2 pin is connected to the R17; the other end of the R17 is connected to the digital signal processor.

[0016] Preferably, the front end of the channel CH1 and the channel CH2 is connected to the safety torque off external input signal; the rear end of the channel CH1 is connected to the digital signal processor, the buffer 1 and the buffer 3; the rear end of the channel CH2 is connected to the digital signal processor, the buffer 2 and the buffer 3.

[0017] Compared with the prior art, the utility model has the beneficial effects that:

[0018] The application realizes real-time monitoring and feedback of safety torque off efficiency through the close contact and multiple diagnosis of each link of safety torque off, compared with the prior art, under the condition of not increasing too many lines and costs, the overall reliability and safety are improved, and the standards of EN ISO13849-1 PL = e and IEC 61508 SIL3 are met. BRIEF DESCRIPTION OF DRAWINGS

[0019] Fig. 1 It is the circuit block diagram of the utility model;

[0020] Fig. 2 It is the circuit diagram of the utility model specific implementation. DETAILED DESCRIPTION

[0021] The technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model, obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the protection scope of the utility model.

[0022] In the description of the utility model, it is understood that the terms "up", "down", "front", "back", "left", "right", "top", "bottom", "in", "out" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation of the utility model.

[0023] Embodiment:

[0024] Please refer to Figs. 1-2 The utility model provides a technical scheme:

[0025] The application relates to a self-monitoring and diagnosing hardware circuit of safe torque off, which comprises channels CH1 and CH2, a digital signal processor (MCU), buffers 1, 2 and 3, a state feedback circuit, a driving circuit, a safe torque off, a power supply VCC, a power supply BP and IGBT, after the MCU is normally started, an enabling signal of the buffer 3 and the power supply BP of the state feedback circuit are generated, then the buffer 3 is firstly diagnosed, and then the buffers 1 and 2 are diagnosed; if the diagnosis result is abnormal, any driving output action is immediately prohibited, and abnormal alarm information is sent to a display screen; if the diagnosis result is normal, the next action is performed, so that the basic safety and reliability of the system are ensured; external input signals enter from STO1 and STO2 of the channels CH1 and CH2, and then are transmitted to the MCU, the MCU analyzes the transmitted signals; if the signals are normal, driving signals are normally output according to the request; if the signals are abnormal, the output of the driving signals is immediately stopped, so that the rotation of a motor is stopped, and abnormal alarm information is transmitted to the display screen; if the signals transmitted from the channels CH1 and CH2 are all abnormal, an external response device is informed through the state feedback circuit, at this time, the STO has entered the highest safety state, the channel CH1 comprises C2, C3, C4, C5, C6, C7, R1, R2, R3, R4, R5, R6, a voltage stabilizing tube ZD1, an optical coupler PC1 and an optical coupler PC2; the channel CH2 comprises C8, C9, C10, C11, C12, C13, R7, R8, R11, R10, R12, R13, R14, a voltage stabilizing tube ZD2, an optical coupler PC3 and an optical coupler PC4;

[0026] The state feedback circuit comprises a capacitor C14, a resistor R18, a resistor R17, a triode Q1, an optical coupler PC5;

[0027] An enabling end of the buffer 1 is connected with a common point of the resistor R5 and the capacitor C5, a diagnosis signal input end, an output end and a PWM signal receiving end of the buffer 1 are connected with the digital signal processor, a PWM signal output end of the buffer 1 is connected with a PWM signal input end of the buffer 2, the diagnosis signal output end of the buffer 1 is also connected with a resistor R15, and the other end of the resistor R15 is connected with the power supply VCC; after the MCU is normally started, a diagnosis signal is given to the buffer 1, then the buffer 1 processes the received diagnosis signal and feeds back the diagnosis signal to the MCU; if the signal received by the MCU is normal, the next normal action of the system is performed; if the signal received by the MCU is abnormal, the MCU prohibits all the driving signal sending actions, and sends related abnormal alarm information to the display screen; since the enabling signal of the buffer 1 is given by the channel CH1, if the signal given by the channel CH1 is abnormal, the buffer 1 immediately closes the transmission channel and stops the transmission of the PWM signal to the next stage;

[0028] The enable end of the buffer 2 is connected with the common point of the resistance R12 and the capacitor C11, the diagnostic signal input end and the output end of the buffer 2 are connected with the digital signal processor, the diagnostic signal output end of the buffer 2 is also connected with R16, the other end of the resistance R16 is connected with the power supply VCC, the PWM signal output end of the buffer 1 is connected with the PWM signal input end of the buffer 2, the PWM signal output end of the buffer 2 is connected with the driving circuit, the driving circuit of the buffer 2 is connected with the IGBT, the output end of the IGBT is connected with the motor to control the operation of the motor. After the MCU is normally started, a diagnostic signal is given to the buffer 2, then the buffer 2 processes the received diagnostic signal and feeds back to the MCU. If the signal received by the MCU is normal, the system performs the next normal action; if the signal received by the MCU is abnormal, the MCU will prohibit all actions of sending driving signals, and at the same time sends related abnormal alarm information to the display screen. Since the enable signal of the buffer 2 is given by the channel CH2, if the signal sent by the channel CH2 is abnormal, the buffer 2 will immediately close the transmission channel and stop the transmission of the PWM signal to the next stage.

[0029] The enable end of the buffer 3 is connected with the resistance R9, the other end of the resistance R9 is connected with the power supply VCC, the output end of the buffer 3 is connected with the right end of R14 and the digital signal processor, the left end of the resistance R14 is connected with the 2 pin of the photo-coupler PC2 and PC4, the input end and the enable end of the buffer 3 are also connected with the digital signal processor. After the MCU is normally started, a normal enable signal is given to the buffer 3, then a diagnostic signal is sent to the input end of the buffer 3, the buffer 3 processes the signal and sends the signal to the output end to the MCU for feedback, so that the MCU diagnoses whether the buffer 3 is normal. If normal, the MCU will send the required signals of the channels CH1 and CH2 to the buffer 3, and the buffer 3 will transmit the signals to CH1 and CH2; if abnormal, the MCU will prohibit all actions of sending driving signals, and at the same time sends related abnormal alarm information to the display screen.

[0030] The C2, C3 and R2 are connected in parallel between the 1 pin of the optical coupler PC1 and the anode of the voltage stabilizing tube ZD1, the cathode of the voltage stabilizing tube ZD1 is connected to the 2 pin of the optical coupler PC1, and the anode is connected to the lower end of R2; one end of R4 is connected to the lower end of R2, and the other end is connected to the 4 pin of the optical coupler PC2; the C6 is connected in parallel to the 3, 4 pins of the optical coupler PC2, one end of R1 is connected to the 4 pin of the optical coupler PC1, and the other end is connected to the power supply VCC; one end of R3 is connected to the 4 pin of the optical coupler PC1, and the other end is connected to the capacitor C4, one end of the capacitor C4 is connected to the ground GND, and the other end is connected to the right end of R3, the common point of R3 and C4 is connected to the digital signal processor; one end of R5 is connected to the 4 pin of the optical coupler PC1, and the other end is connected to C5, one end of C5 is connected to the ground GND, and the other end is connected to the right end of R5, the common point of R5 and C5 is connected to the digital signal processor, R6 and C7 are connected in parallel to the 1, 2 pins of the optical coupler PC2, when the buffer 3 works normally, the optical coupler PC2 is switched from the off state to the on state, at this time, the external signal enters from STO1, the optical coupler PC1 is switched from the off state to the on state, the 4 pin of the optical coupler PC1 changes from high level to low level, and is transmitted to the MCU.

[0031] The C9, C10 and R8 are connected in parallel between the 1 pin of the optical coupler PC3 and the anode of the voltage stabilizing tube ZD2, the cathode of the voltage stabilizing tube ZD2 is connected to the 2 pin of the optical coupler PC3, and the anode is connected to the lower end of R8; one end of R11 is connected to the lower end of R8, and the other end is connected to the 4 pin of the optical coupler PC4, the C13 is connected in parallel to the 3, 4 pins of the optical coupler PC4, one end of R7 is connected to the 4 pin of the optical coupler PC3, and the other end is connected to the power supply VCC; one end of R10 is connected to the 4 pin of the optical coupler PC3, and the other end is connected to C8, one end of C8 is connected to the ground GND, and the other end is connected to the right end of R10, the common point of R10 and C8 is connected to the digital signal processor, one end of R12 is connected to the 4 pin of the optical coupler PC1, and the other end is connected to C11, one end of C11 is connected to the ground GND, and the other end is connected to the right end of R12, the common point of R12 and C11 is connected to the digital signal processor, R13 and C12 are connected in parallel to the 1, 2 pins of the optical coupler PC4, the 2 pins of the optical coupler PC2 and the optical coupler PC4 are connected to R14, the other end of R14 is connected to the buffer 3, when the buffer 3 works normally, the optical coupler PC4 is switched from the off state to the on state, at this time, the external signal enters from STO2, the optical coupler PC3 is switched from the off state to the on state, the 4 pin of the optical coupler PC3 changes from high level to low level, and is transmitted to the MCU.

[0032] The C14 is connected in parallel between the collector and the emitter of the triode Q1, the collector of the triode Q1 is connected to the 4-pin of the optocoupler PC5, the base is connected to the 3-pin of the optocoupler PC5, and the emitter is connected to the ground SD. One end of the R18 is connected to the base of the triode Q1, and the other end is connected to the ground SD. The 1-pin of the optocoupler PC5 is connected to the power supply BP, and the 2-pin is connected to the R17. When the signals transmitted to the MCU of the channel CH1 and the channel CH2 are both abnormal, the MCU will send a signal (low level) to the R17. At this time, the optocoupler PC5 changes from the closed state to the conducting state. This action will cause the customer's external response device to perform related actions, thereby informing the customer that the STO has entered the highest safety state.

[0033] The front ends of the channel CH1 and the channel CH2 are connected to the safety torque shutdown external input signal. The rear end of the channel CH1 is connected to the digital signal processor, the buffer 1, and the buffer 3. The rear end of the channel CH2 is connected to the digital signal processor, the buffer 2, and the buffer 3. The channel CH1 and the channel CH2 have consistent line configurations. Taking the channel CH1 as an example, the isolation conversion circuit is composed of two optocouplers 1 and 2. The primary side of the optocoupler 2 is connected to the buffer 3. If the isolation conversion circuit needs to be turned on in the normal working mode, the primary side of the optocoupler 2 needs to receive the correct signal. The function of the optocoupler 1 is to convert the STO external input signal into a signal that can be received by the rear end.

[0034] The rear end of the optocoupler 1 has two filter circuits 1 and 2. The output signal of the filter circuit 1 is transmitted to the digital signal processor. If the signal is abnormal, the digital signal processor will close the output of the PWM signal and send an abnormal alarm information to the display screen. The output signal of the filter circuit 2 is transmitted to the buffer 1. If the signal is abnormal, the buffer 1 will close the channel and stop transmitting the PWM signal to the next level.

[0035] The digital signal processor mainly processes the signals transmitted by the CH1 and CH2 channels, diagnoses the status of the three buffers, provides an enable signal to the buffer 3, provides a power supply BP to the state feedback circuit, provides a signal to open the isolation conversion circuit for the channel CH1 and CH2, sends the STO state information and the PWM driving signal to the outside.

[0036] The buffer 3 mainly transmits the signal to open the normal working mode for the channel CH1 and CH2. The buffer 1 and the buffer 2 mainly transmit the PWM signal sent by the digital signal processor.

[0037] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the appended claims rather than the above description. Therefore, it is intended that all changes that fall within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0038] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-monitoring and diagnostic safe torque off hardware circuit, comprising a channel CH1, a channel CH2, a digital signal processor, a buffer 1, a buffer 2, a buffer 3, a state feedback circuit, a drive circuit, a safe torque off, a power supply VCC, a power supply BP, and an IGBT, characterized in that: The channel CH1 includes C2, C3, C4, C5, C6, C7, R1, R2, R3, R4, R5, R6, a voltage regulator ZD1, an optocoupler PC1, and an optocoupler PC2; the channel CH2 includes C8, C9, C10, C11, C12, C13, R7, R8, R11, R10, R12, R13, R14, a voltage regulator ZD2, an optocoupler PC3, and an optocoupler PC4; The state feedback circuit includes capacitor C14, R18, R17, transistor Q1, and optocoupler PC5; The enable terminal of the buffer 1 is connected to the common point of the resistor R5 and the capacitor C5. The diagnostic signal input terminal, output terminal, and PWM signal receiving terminal of the buffer 1 are all connected to the digital signal processor. The PWM signal output terminal of the buffer 1 is connected to the PWM signal input terminal of the buffer 2. The diagnostic signal output terminal of the buffer 1 is also connected to the resistor R15. The other end of the resistor R15 is connected to the power supply VCC. The enable terminal of the buffer 2 is connected to the common point of the resistor R12 and the capacitor C11. The diagnostic signal input and output terminals of the buffer 2 are both connected to the digital signal processor. The diagnostic signal output terminal of the buffer 2 is also connected to R16. The other end of the resistor R16 is connected to the power supply VCC. The PWM signal output terminal of the buffer 1 is connected to the PWM signal input terminal of the buffer 2. The PWM signal output terminal of the buffer 2 is connected to the drive circuit. The drive circuit of the buffer 2 is connected to the IGBT. The output terminal of the IGBT is connected to the motor. The enable end of the buffer 3 is connected to a resistor R9, the other end of the resistor R9 is connected to the power supply VCC, the output end of the buffer 3 is connected to the right end of R14 and the digital signal processor, the left end of R14 is connected to pin 2 of the optocouplers PC2 and PC4, and the input end and enable end of the buffer 3 are also connected to the digital signal processor.

2. A self-monitoring and diagnostic safe torque off hardware circuit according to claim 1, characterized in that: The C2, C3 and R2 are connected in parallel between pin 1 of the optocoupler PC1 and the anode of the voltage regulator ZD1. The cathode of the voltage regulator ZD1 is connected to pin 2 of the optocoupler PC1, and its anode is connected to the lower end of R2. One end of the R4 is connected to the lower end of R2, and the other end is connected to pin 4 of the optocoupler PC2. The C6 is connected in parallel to pins 3 and 4 of the optocoupler PC2. One end of the R1 is connected to pin 4 of the optocoupler PC1 and one end is connected to the power supply VCC. One end of the R3 is connected to pin 4 of the optocoupler PC1 and one end is connected to capacitor C4. One end of C4 is connected to ground GND and one end is connected to the right end of R3. The common point of R3 and C4 is connected to the digital signal processor. One end of the R5 is connected to pin 4 of the optocoupler PC1 and one end is connected to C5. One end of C5 is connected to ground GND and one end is connected to the right end of R5. The common point of R5 and C5 is connected to the digital signal processor. The R6 and C7 are connected in parallel to pins 1 and 2 of the optocoupler PC2.

3. The hardware circuit of the self-monitoring and diagnostic safe torque off system according to claim 1, characterized in that: The C9, C10 and R8 are connected in parallel between pin 1 of the optocoupler PC3 and the anode of the voltage regulator ZD2. The cathode of the voltage regulator ZD2 is connected to pin 2 of the optocoupler PC3, and its anode is connected to the lower end of R8. One end of the R11 is connected to the lower end of R8, and the other end is connected to pin 4 of the optocoupler PC4. The C13 is connected in parallel to pins 3 and 4 of the optocoupler PC4. One end of the R7 is connected to pin 4 of the optocoupler PC3 and the other end is connected to the power supply VCC. One end of the R10 is connected to pin 4 of the optocoupler PC3 and the other end is connected to C8. One end of C8 is connected to ground GN. D, one end is connected to the right end of R10, the common point of R10 and C8 is connected to the digital signal processor, one end of R12 is connected to pin 4 of the optocoupler PC3, and one end is connected to C11, one end of C11 is grounded GND, and one end is connected to the right end of R12, the common point of R12 and C11 is connected to the digital signal processor, R13 and C12 are connected in parallel to pins 1 and 2 of the optocoupler PC4, pin 2 of the primary side of the optocoupler PC2 and optocoupler PC4 is connected to R14, and the other end of R14 is connected to buffer 3.

4. The hardware circuit of the self-monitoring and self-diagnosing safe torque off system according to claim 1, characterized in that: The C14 is connected in parallel between the collector and emitter of the transistor Q1. The collector of the transistor Q1 is connected to pin 4 of the optocoupler PC5, the base is connected to pin 3 of the optocoupler PC5, and the emitter is connected to the ground SD. One end of the R18 is connected to the base of the transistor Q1 and the other end is connected to the ground SD. Pin 1 of the optocoupler PC5 is connected to the power supply BP, and pin 2 is connected to R17. The other end of R17 is connected to the digital signal processor.

5. The hardware circuit of the self-monitoring and self-diagnosing safe torque off system according to claim 1, characterized in that: The front ends of the channels CH1 and CH2 are connected to the safety torque off external input signal, the rear ends of the channel CH1 are connected to the digital signal processor, buffer 1 and buffer 3; the rear ends of the channel CH2 are connected to the digital signal processor, buffer 2 and buffer 3.

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