Motor software and hardware redundancy control method

Abstract

The invention discloses a motor software and hardware redundancy control method, which relates to the field of motor control, and comprises the following steps: a software and hardware control parallel mode is adopted to connect and control the start and stop of a motor, the software control is realized based on a PLC (Programmable Logic Controller), and the hardware control is realized based on a logic circuit; the invention discloses a software and hardware redundancy control method for a motor, which is a control method for improving the reliability and the stability of a system through software and hardware redundancy design by adopting a software and hardware control parallel mode for connection, and in the method, a motor can be started through a software control circuit or a hardware control circuit; the motor cannot be started completely even if the software or hardware control circuit fails independently, so that the continuous operation of the system is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of motor control, and in particular to a motor software and hardware redundancy control method. Background Art

[0002] The application of motors in ships has become an important part of modern navigation technology. In the auxiliary systems of ships, motors are widely used in equipment such as pumps, fans, compressors and generator sets to ensure the normal operation of ships. These devices play an important role in the ship system. Motors ensure the normal operation of ships by connecting and driving these devices.

[0003] Since the starting and stopping of the motor is the key performance of the equipment and is crucial to the reliability of the system, the existing solutions only have software control or hardware control, which is not very reliable. Once the software crashes or the operation button fails, the motor will be completely unable to start.

[0004] To this end, we provide a motor software and hardware redundant control method to solve the above problems. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a motor software and hardware redundant control method to solve the problem that the existing solutions only have software control or hardware control, which is not reliable and once the software crashes or the operation button fails, the motor will be completely unable to start.

[0006] In order to achieve the above object, the present invention adopts a motor software and hardware redundancy control method, comprising:

[0007] Use software and hardware control in parallel to connect and control the start and stop of the motor;

[0008] Among them, the software control is realized based on the PLC programmable controller; the hardware control is realized based on the logic circuit; the hardware part includes the knob SA1, the operation button SB1, the operation button SB2, the remote control start signal ON1, the remote control stop signal OFF1, the relay KA1, the relay KA2, the thermal relay FR1 and the contactor KM1;

[0009] The PLC programmable controller is responsible for information processing and outputting external control signals;

[0010] The PLC programmable controller is used to collect the switch signal of the knob SA1 to realize the judgment of the remote control and local status; the PLC programmable controller is used to collect the switch signal of the operation button SB1 and the remote control start signal, and control the relay KA1 to control the start and stop logic circuit of the motor; the PLC programmable controller is used to collect the switch signal of the operation button SB2 and the remote control stop signal, and control the relay KA2 to control the stop logic circuit of the motor; the PLC programmable controller is used to collect the switch signal of the thermal relay FR1 to disconnect the control circuit of the motor.

[0011] As a further optimization of the above solution, the knob SA1 has normally open contacts SA1-1, SA1-2 and normally closed contacts SA1-3, SA1-4;

[0012] The operation button SB1 has normally open contacts SB1-1 and SB1-2;

[0013] The operation button SB2 has normally closed contacts SB2-1 and SB2-2;

[0014] The relay KA1 has normally open contacts KA1-1 and KA1-2;

[0015] The relay KA2 has normally closed contacts KA2-1 and KA2-2;

[0016] Among them, the normally open contact SA1-1 is connected to DC24V+ and one end of the normally open contact SB1-1 respectively, and is used to switch the local mode control circuit;

[0017] Normally open contact SA1-3 is connected to DC24V+ and one end of normally open contact KA1-1 respectively, and is used to switch the remote control mode control circuit;

[0018] The normally open contact SB1-1 is connected to one end of the normally open contact SA1-1 and the normally closed contact SB2-1 respectively, and is used to control the motor starting circuit in the local state;

[0019] The normally closed contact SB2-1 is connected to one end of the normally open contact SB1-1 and the normally closed contact KA2-2 respectively, and is used to control the motor stop circuit in the local state.

[0020] As a further optimization of the above scheme, the PLC programmable controller has a plurality of pins, including 1M, 1L+, Q1, Q2, Q3, Q4, 2M, 2L+, Q5, Q6, Q7, Q8, EARTH, 3M, 3L+, I1, I2, I3, I4, 4M, 4L+, I5, I6, I7 and I8;

[0021] Among them, M stands for DC24V-, that is, the negative pole of the 24V DC power supply; L stands for DC24V+, that is, the positive pole of the 24V DC power supply; Q stands for passive output; I stands for passive input; EARTH stands for the ground terminal;

[0022] Among them, two EARTH pins are provided, and each of the remaining pins except EARTH pins on the PLC programmable controller is provided with one pin.

[0023] As a further optimization of the above scheme, the normally open contacts SA1-2 are respectively connected to the DC24V+ and I1 terminals to input the local mode status signal to the PLC programmable controller;

[0024] The normally closed contacts SA1-4 are connected to the DC24V+ and I2 terminals respectively, and are used to input the motor remote control mode status signal to the PLC programmable controller;

[0025] The normally open contacts SB1-2 are connected to the DC24V+ and I3 terminals respectively, and are used to input the motor start button signal to the PLC programmable controller;

[0026] The normally closed contact SB2-2 is connected to the DC24V+ and I4 terminals and is used to input the motor stop button signal to the PLC programmable controller.

[0027] As a further optimization of the above scheme, the remote control start signal ON1 is connected to the DC24V+ and I6 terminals respectively, so as to input the external start signal to the PLC programmable controller;

[0028] The remote control stop signal OFF1 is connected to the DC24V+ and I7 terminals respectively, and is used to input the external stop signal to the PLC programmable controller.

[0029] As a further optimization of the above solution, the relay KA1 and the relay KA2 both have coil pins A1 and A2;

[0030] The coil pin A1 of the relay KA1 is connected to the Q1 end, and the coil pin A2 of the relay KA1 is connected to DC24V-.

[0031] As a further optimization of the above solution, the normally open contact KA1-1 is connected to one end of the normally closed contact SA1-3 and the normally closed contact KA2-1 respectively;

[0032] The normally open contact KA1-2 is connected to one end of the normally closed contact SA1-1 and the normally open contact SB1-1 respectively, and the relay KA1 is used to control the motor starting circuit.

[0033] As a further optimization of the above solution, the coil pin A1 of the relay KA2 is connected to the Q2 end, and the coil pin A2 of the relay KA2 is connected to DC24V-;

[0034] The thermal relay FR1 has a normally closed contact FR1-1 and a normally open contact FR1-2;

[0035] The normally closed contact KA2-1 is connected to one end of the normally open contact KA1-1 and the normally closed contact FR1-1 respectively; the normally closed contact KA2-2 is connected to one end of the normally closed contact SB2-1 and the normally closed contact FR1-1 respectively, and the relay KA2 is used to control the motor stop circuit;

[0036] When the normally open contact SA1-1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-2 through the I1 port, determines that the control circuit is in the local control state, presses the operation button SB1, and the SB1-1 contact and SB1-2 contact are instantly closed. The PLC programmable controller collects the operation button SB1-2 signal through the I3 port, the contactor KM1 and the relay KA1 are actuated, the contactor KM1-1 contact and the relay KA1-2 contact change from normally open to normally closed, the motor control circuit is closed, and the motor starts at this time;

[0037] If the PLC program fails, the contactor KM1-1 will be controlled and closed, and the motor control circuit will start. If the operation button SB1 fails, the remote control start signal will be used to control the relay KA1, and the contact KA1-2 of the relay KA1 will be activated.

[0038] As a further optimization of the above scheme, the normally closed contact FR1-1 is respectively connected to one end of the normally closed contact KA2-2 and the coil pin A1 of the contactor KM1; the normally open contact FR1-2 is respectively connected to the DC24V+ and I5 terminals, and the thermal relay FR1 is used to protect the motor.

[0039] As a further optimization of the above solution, the coil pin A2 of the contactor KM1 is connected to DC24V-;

[0040] When the normally open contact SA1-1 of the knob SA1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-2 through the I1 port and determines that the control circuit is in the local control state;

[0041] If the motor needs to stop after starting, press the operating button SB2, the operating SB2-1 contact is instantly disconnected, and the SB2-2 contact is instantly closed. The PLC programmable controller collects the operating button SB2-2 signal through the I4 port, the contactor KM1 and the relay KA1 stop working, the contactor KM1-1 contact and the relay KA1-2 contact return to the initial state, from normally closed to normally open, and the motor control circuit is disconnected;

[0042] If the PLC program fails, the contactor KM1 is cut off by operating the button SB2 in hardware, so that the contactor KM1-1 contacts are disconnected, and the motor stops working.

[0043] The motor software and hardware redundancy control method of the present invention has the following beneficial effects:

[0044] The present invention discloses a motor software and hardware redundant control method, which is a control method that adopts software and hardware control in parallel to improve system reliability and stability through software and hardware redundant design. In this method, the motor can be started by software or hardware control circuits, and failure of the software or hardware control circuit alone will not cause the motor to be completely unable to start, thereby ensuring the continuous operation of the system.

[0045] With reference to the following description and drawings, a specific embodiment of the present invention is disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the scope of the embodiments of the present invention is not limited thereby, and within the spirit and scope of the appended claims, the embodiments of the present invention include many changes, modifications and equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the structure of the motor software and hardware redundancy control circuit of the present invention;

[0047] Figure 2 It is a schematic diagram of the structure of a PLC programmable controller of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below through the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0049] Please refer to the instruction manual Figure 1-2The present invention provides a technical solution: a motor software and hardware redundant control method, including: a PLC programmable controller, a knob SA1, an operation button SB1, an operation button SB2, a remote control start signal ON1, a remote control stop signal OFF1, a relay KA1, a relay KA2, a thermal relay FR1, and a contactor KM1.

[0050] The PLC programmable controller is responsible for information processing and outputting external control signals. The PLC programmable controller has multiple pins, including 1M, 1L+, Q1, Q2, Q3, Q4, 2M, 2L+, Q5, Q6, Q7, Q8, EARTH, 3M, 3L+, I1, I2, I3, I4, 4M, 4L+, I5, I6, I7 and I8;

[0051] Among them, M stands for DC24V-, that is, the negative pole of the 24V DC power supply; L stands for DC24V+, that is, the positive pole of the 24V DC power supply; Q stands for passive output; I stands for passive input; EARTH stands for the ground terminal;

[0052] Among them, two EARTH pins are provided, and each of the remaining pins except EARTH pins on the PLC programmable controller is provided with one pin.

[0053] The PLC programmable controller is used to collect the switch signal of the knob SA1 to realize the remote control and local status judgment.

[0054] The PLC programmable controller is used to collect the switch signal of the operation button SB1 and the remote control start signal, control the relay KA1, and realize the control of the start and stop logic circuit of the motor.

[0055] The PLC programmable controller is used to collect the switch signal of the operation button SB2 and the remote control stop signal, control the relay KA2, and realize the control of the motor's stop logic circuit.

[0056] The PLC programmable controller is used to collect the switch signal of the thermal relay FR1 to realize the control circuit of the motor disconnection.

[0057] Furthermore, a group of normally open contacts SA1-1 of the knob SA1 are respectively connected to DC24V+ and one end of a group of normally open contacts SB1-1 of the operation button SB1, for switching the local mode control circuit, a group of normally open contacts SA1-2 of the knob SA1 are respectively connected to DC24V+ and the I1 end of the PLC programmable controller, for inputting the local mode status signal to the PLC programmable controller, a group of normally open contacts SA1-3 of the knob SA1 are respectively connected to DC24V+ and one end of a group of normally open contacts KA1-1 of the relay KA1, for switching the remote control mode control circuit, a group of normally closed contacts SA1-4 of the knob SA1 are respectively connected to DC24V+ and the I2 end of the PLC programmable controller, for inputting the motor remote control mode status signal to the PLC programmable controller.

[0058] Furthermore, a group of normally open contacts SB1-1 of the operating button SB1 are respectively connected to a group of normally open contacts SA1-1 of the knob SA1 and one end of a group of normally closed contacts SB2-1 of the operating button SB2, for controlling the motor starting circuit in the local state; a group of normally open contacts SB1-2 of the operating button SB1 are respectively connected to DC24V+ and the I3 end of the PLC programmable controller, for inputting the motor start button signal to the PLC programmable controller.

[0059] Furthermore, a group of normally closed contacts SB2-1 of the operating button SB2 are respectively connected to a group of normally closed contacts SB1-1 of the operating button SB1 and one end of a group of normally closed contacts KA2-2 of the relay KA2, for controlling the motor stop circuit in the local state; a group of normally closed contacts SB2-2 of the operating button SB2 are connected to DC24V+ and the I4 end of the PLC programmable controller, for inputting the motor stop button signal to the PLC programmable controller.

[0060] Furthermore, the remote control start signal ON1 is respectively connected to DC24V+ and the I6 terminal of the PLC programmable controller, and is used to input the external start signal to the PLC programmable controller. The remote control stop signal OFF1 is respectively connected to DC24V+ and the I7 terminal of the PLC programmable controller, and is used to input the external stop signal to the PLC programmable controller.

[0061] The coil pin A1 of relay KA1 is connected to the Q1 end of the PLC programmable controller, and the coil pin A2 of relay KA1 is connected to DC24V-; a group of normally open contacts KA1-1 of relay KA1 are respectively connected to a group of normally closed contacts SA1-3 of knob SA1 and one end of a group of normally closed contacts KA2-1 of relay KA2; a group of normally open contacts KA1-2 of relay KA1 are respectively connected to a group of normally closed contacts SA1-1 of knob SA1 and one end of a group of normally open contacts SB1-1 of operating button SB1. Relay KA1 is used to control the motor starting circuit.

[0062] The coil pin A1 of relay KA2 is connected to the Q2 end of the PLC programmable controller, and the coil pin A2 of relay KA2 is connected to DC24V-; a group of normally closed contacts KA2-1 of relay KA2 are respectively connected to a group of normally open contacts KA1-1 of relay KA1 and one end of a group of normally closed contacts FR1-1 of thermal relay FR1; a group of normally closed contacts KA2-2 of relay KA2 are respectively connected to a group of normally closed contacts SB2-1 of operation button SB2 and one end of a group of normally closed contacts FR1-1 of thermal relay FR1. Relay KA2 is used to control the motor stop circuit.

[0063] A group of normally closed contacts FR1-1 of thermal relay FR1 are respectively connected to one end of a group of normally closed contacts KA2-2 of relay KA2 and coil pin A1 of contactor KM1; a group of normally open contacts FR1-2 of thermal relay FR1 are respectively connected to DC24V+ and I5 end of PLC programmable controller. Thermal relay FR1 is used to protect the motor.

[0064] The coil pin A2 of contactor KM1 is connected to DC24V-.

[0065] like Figure 1 and Figure 2 As shown, when the normally open contact SA1-1 of the knob SA1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-2 through the I1 port, and determines that the control circuit is in the local control state. The SB1-1 contact and the SB1-2 contact of the operation button SB1 are pressed and closed instantly. The PLC programmable controller collects the operation button SB1-2 signal through the I3 port, and the contactor KM1 and the relay KA1 are actuated. The contact of the contactor KM1-1 and the contact of the relay KA1-2 change from normally open to normally closed, and the motor control circuit is closed, and the motor starts.

[0066] If the PLC program fails, you can still control contactor KM1 in hardware by operating button SB1 to close the contact of contactor KM1-1, and the control circuit of the motor starts; if operating button SB1 fails, you can control relay KA1 through remote control start signal, and the contact KA1-2 of relay KA1 will start, and the control circuit of the motor will start.

[0067] When the normally open contact SA1-1 of the knob SA1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-2 through the I1 port, and determines that the control circuit is in the local control state. For example, after the motor starts, when it needs to stop, press the operation button SB2, the operation button SB2-1 contact is instantly disconnected, and the SB2-2 contact is instantly closed. The PLC programmable controller collects the operation button SB2-2 signal through the I4 port, the contactor KM1 and the relay KA1 stop working, the contactor KM1-1 contact and the relay KA1-2 contact return to the initial state, from normally closed to normally open, the motor control circuit is disconnected, and the motor stops working.

[0068] If the PLC program fails, the contactor KM1 can still be cut off by operating the button SB2 in hardware, so that the contactor KM1-1 contacts are disconnected, and the motor stops working; if the operating button SB2 fails, the relay KA1 can be restored by the remote control stop signal, so that the contact of relay KA1-1 is disconnected, and the relay KA2 is controlled to act instantly, and the contact KA2-2 of relay KA2 is disconnected instantly, and then restored to the closed state, and the motor stops working.

[0069] When the normally closed contact SA1-1 of the knob SA1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-4 through the I2 port, determines that the control circuit is in the remote control state, and inputs the remote control start signal to the I6 port of the PLC programmable controller to control the relay KA1 to operate, so that the relay KA1-1 contact is closed, and the motor starts. The remote control stop signal is input to the I7 port of the PLC programmable controller to restore the relay KA1, so that the relay KA1-1 contact is disconnected, and the relay KA2 is controlled to act instantaneously, so that the relay KA2-1 contact is instantly disconnected, and then restored to the closed state, and the motor stops working.

[0070] The PLC programmable controller collects the signal of the normally open contact FR1-2 of the thermal relay FR1 through the I5 port. When the motor is overloaded, the thermal relay FR1 is activated, and the thermal relay FR1-1 changes from normally closed to normally open, cutting off the operation of the motor.

[0071] It is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent substitution or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A motor software and hardware redundancy control method, characterized in that: include: Use software and hardware control in parallel to connect and control the start and stop of the motor; Among them, software control is realized based on PLC programmable controller; The hardware control is realized based on the logic circuit; the hardware part includes the knob SA1, the operation button SB1, the operation button SB2, the remote control start signal ON1, the remote control stop signal OFF1, the relay KA1, the relay KA2, the thermal relay FR1 and the contactor KM1; The PLC programmable controller is responsible for information processing and outputting external control signals; The PLC programmable controller is used to collect the switch signal of the knob SA1 to realize the judgment of the remote control and local status; the PLC programmable controller is used to collect the switch signal of the operation button SB1 and the remote control start signal, and control the relay KA1 to control the start and stop logic circuit of the motor; the PLC programmable controller is used to collect the switch signal of the operation button SB2 and the remote control stop signal, and control the relay KA2 to control the stop logic circuit of the motor; the PLC programmable controller is used to collect the switch signal of the thermal relay FR1 to disconnect the control circuit of the motor.

2. The motor software and hardware redundancy control method according to claim 1, characterized in that: The knob SA1 has normally open contacts SA1-1, SA1-2 and normally closed contacts SA1-3, SA1-4; The operation button SB1 has normally open contacts SB1-1 and SB1-2; The operation button SB2 has normally closed contacts SB2-1 and SB2-2; The relay KA1 has normally open contacts KA1-1 and KA1-2; The relay KA2 has normally closed contacts KA2-1 and KA2-2; Among them, the normally open contact SA1-1 is connected to DC24V+ and one end of the normally open contact SB1-1 respectively, and is used to switch the local mode control circuit; Normally open contact SA1-3 is connected to DC24V+ and one end of normally open contact KA1-1 respectively, and is used to switch the remote control mode control circuit; The normally open contact SB1-1 is connected to one end of the normally open contact SA1-1 and the normally closed contact SB2-1 respectively, and is used to control the motor starting circuit in the local state; The normally closed contact SB2-1 is connected to one end of the normally open contact SB1-1 and the normally closed contact KA2-2 respectively, and is used to control the motor stop circuit in the local state.

3. A motor software and hardware redundancy control method according to claim 2, characterized in that: The PLC programmable controller has a plurality of pins, including 1M, 1L+, Q1, Q2, Q3, Q4, 2M, 2L+, Q5, Q6, Q7, Q8, EARTH, 3M, 3L+, I1, I2, I3, I4, 4M, 4L+, I5, I6, I7 and I8; Among them, M stands for DC24V-, that is, the negative pole of the 24V DC power supply; L stands for DC24V+, that is, the positive pole of the 24V DC power supply; Q stands for passive output; I stands for passive input; EARTH stands for the ground terminal; Among them, two EARTH pins are provided, and each of the remaining pins except EARTH pins on the PLC programmable controller is provided with one pin.

4. A motor software and hardware redundancy control method according to claim 3, characterized in that: The normally open contacts SA1-2 are connected to the DC24V+ and I1 terminals respectively, and input the local mode status signal to the PLC programmable controller; The normally closed contacts SA1-4 are connected to the DC24V+ and I2 terminals respectively, and are used to input the motor remote control mode status signal to the PLC programmable controller; The normally open contacts SB1-2 are connected to the DC24V+ and I3 terminals respectively, and are used to input the motor start button signal to the PLC programmable controller; The normally closed contact SB2-2 is connected to the DC24V+ and I4 terminals and is used to input the motor stop button signal to the PLC programmable controller.

5. The motor software and hardware redundancy control method according to claim 3 is characterized in that: The remote control start signal ON1 is connected to the DC24V+ and I6 terminals respectively, and is used to input the external start signal to the PLC programmable controller; The remote control stop signal OFF1 is connected to the DC24V+ and I7 terminals respectively, and is used to input the external stop signal to the PLC programmable controller.

6. The motor software and hardware redundancy control method according to claim 3 is characterized by: The relay KA1 and the relay KA2 both have coil pins A1 and A2; The coil pin A1 of the relay KA1 is connected to the Q1 end, and the coil pin A2 of the relay KA1 is connected to DC24V-.

7. A motor software and hardware redundancy control method according to claim 6, characterized in that: The normally open contact KA1-1 is connected to one end of the normally closed contact SA1-3 and one end of the normally closed contact KA2-1 respectively; The normally open contact KA1-2 is connected to one end of the normally closed contact SA1-1 and the normally open contact SB1-1 respectively, and the relay KA1 is used to control the motor starting circuit.

8. A motor software and hardware redundancy control method according to claim 7, characterized in that: The coil pin A1 of the relay KA2 is connected to the Q2 end, and the coil pin A2 of the relay KA2 is connected to DC24V-; The thermal relay FR1 has a normally closed contact FR1-1 and a normally open contact FR1-2; The normally closed contact KA2-1 is connected to one end of the normally open contact KA1-1 and the normally closed contact FR1-1 respectively; the normally closed contact KA2-2 is connected to one end of the normally closed contact SB2-1 and the normally closed contact FR1-1 respectively, and the relay KA2 is used to control the motor stop circuit; When the normally open contact SA1-1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-2 through the I1 port, determines that the control circuit is in the local control state, presses the operation button SB1, and the SB1-1 contact and SB1-2 contact are instantly closed. The PLC programmable controller collects the operation button SB1-2 signal through the I3 port, the contactor KM1 and the relay KA1 are actuated, the contactor KM1-1 contact and the relay KA1-2 contact change from normally open to normally closed, the motor control circuit is closed, and the motor starts at this time; If the PLC program fails, the contactor KM1-1 will be controlled and closed, and the motor control circuit will start. If the operation button SB1 fails, the remote control start signal will be used to control the relay KA1, and the contact KA1-2 of the relay KA1 will be activated.

9. A motor software and hardware redundancy control method according to claim 8, characterized in that: The normally closed contact FR1-1 is respectively connected to one end of the normally closed contact KA2-2 and the coil pin A1 of the contactor KM1; the normally open contact FR1-2 is respectively connected to the DC24V+ and I5 terminals, and the thermal relay FR1 is used to protect the motor.

10. A motor software and hardware redundancy control method according to claim 9, characterized in that: The coil pin A2 of the contactor KM1 is connected to DC24V-; When the normally open contact SA1-1 of the knob SA1 is closed, the PLC programmable controller collects the input signal of the operation button SA1-2 through the I1 port and determines that the control circuit is in the local control state; If the motor needs to stop after starting, press the operating button SB2, the operating SB2-1 contact is instantly disconnected, and the SB2-2 contact is instantly closed. The PLC programmable controller collects the operating button SB2-2 signal through the I4 port, the contactor KM1 and the relay KA1 stop working, the contactor KM1-1 contact and the relay KA1-2 contact return to the initial state, from normally closed to normally open, and the motor control circuit is disconnected; If the PLC program fails, the contactor KM1 is cut off by operating the button SB2 in hardware, so that the contactor KM1-1 contacts are disconnected, and the motor stops working.

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