A double four-wire switch machine simulation circuit

Abstract

The application discloses a kind of double four-wire switching machine simulation circuits, belong to switching machine technical field, the circuit is connected with switching machine control circuit by the X1, X2, X3 and X4 contact of 4 core connector, the circuit includes main circuit, first state acquisition circuit and second state acquisition circuit, and main circuit further includes indicating circuit and load circuit;The switching machine state simulated by the present circuit is comprehensive, convenient to arrange, simple to operate, and the number of simulation equipment can be increased or decreased according to the on-site debugging requirement, which significantly improves the on-site debugging efficiency of full electronic interlocking system.

Description

Technical Field

[0001] This invention relates to the field of rail transit, and in particular to the software debugging of a fully electronic execution unit station system for a metro interlocking system, especially to a dual-path four-wire switch machine simulation circuit. Background Technology

[0002] During the laboratory testing and field commissioning phase of the fully electronic interlocking system, functional verification of the switch machine's status control (i.e., "fixed position", "reverse position", "fixed operation", "reverse operation", "phase loss", "squeeze", "overcurrent", "undercurrent") is required. Currently, the main problems are as follows:

[0003] Traditional analog methods are inefficient: They typically involve building temporary analog circuits composed of diodes on an interface cabinet. This method has low integration, requires independent wiring for each simulated switch machine, is cumbersome to operate, has low debugging efficiency, and is prone to errors.

[0004] Therefore, there is an urgent need for a circuit that can quickly and accurately simulate multiple ZD6 four-wire switch machines to meet the requirements of efficient commissioning of the fully electronic interlocking system. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of current all-electronic interlocking system software in laboratory environments and during on-site deployment and debugging of four-wire switch machines, and to provide a multi-channel, independently adjustable, and easily maintainable four-wire switch machine simulation circuit.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a dual-path four-wire switch machine simulation circuit, which is connected to the switch machine control circuit through the X1, X2, X3 and X4 contacts of a 4-core connector. The circuit includes a main circuit, a first state acquisition circuit and a second state acquisition circuit. The main circuit further includes an indication circuit and a load circuit.

[0007] The indication circuit includes: a first double normally open relay DQ1, a second double normally open relay DQ2, a first single normally open relay DQ4, a second single normally open relay DQ5, and an indication diode D1;

[0008] The load circuit includes: a first double normally closed relay DQ6, a second double normally closed relay DQ7, a first load resistor R1, a second load resistor R2, and a third load resistor R3;

[0009] The first state acquisition circuit (connected to X1 and X4) includes: resistor R10, resistor R11, resistor R12, optocoupler OP1, and Zener diode ZD1;

[0010] The second state acquisition circuit (connected to X2 and X4) includes: resistors R13, R14, and R15, optocoupler OP2, and Zener diode ZD2;

[0011] The circuit indicates that terminal 3 of the first normally open contact of the first double normally open relay DQ1 is connected to terminal 3 of the first normally open contact of the second double normally open relay DQ2, and together they are connected to connector contact X3; terminal 4 of the first normally open contact of the first double normally open relay DQ1 is connected to terminal 5 of the second normally open contact of the second double normally open relay DQ2, and together they are connected to the cathode of the indicating diode D1; terminal 6 of the second normally open contact of the first double normally open relay DQ1 is connected to terminal 4 of the normally open contact of the first single normally open relay DQ4, and together they are connected to connector contact X2; terminal 5 of the second normally open contact of the first double normally open relay DQ1 is connected to terminal 4 of the first normally open contact of the second double normally open relay DQ2, and together they are connected to the anode of the indicating diode D1.

[0012] The second normally open contact 6 of the second double normally open relay DQ2 is connected to the normally open contact 3 of the second single normally open relay DQ5, and together they are connected to connector contact X1; the normally open contact 4 of the first single normally open relay DQ4 is connected to the normally open contact 4 of the second single normally open relay DQ5, and together they are connected to the upper end of the first load resistor R1 and the first normally closed contact 3 of the first double normally closed relay DQ6.

[0013] The lower end of the first load resistor R1 in the load circuit is connected to terminal 6 of the second normally closed contact of the first double normally closed relay DQ6, and together they are connected to connector contact X4; the upper end of the second load resistor R2 is connected to terminal 4 of the first normally closed contact of the first double normally closed relay DQ6, and together they are connected to terminal 3 of the first normally closed contact of the second double normally closed relay DQ7; the lower end of the second load resistor R2 is connected to terminal 5 of the second normally closed contact of the first double normally closed relay DQ6, and together they are connected to terminal 6 of the second normally closed contact of the second double normally closed relay DQ7; the upper end of the third load resistor R3 is connected to terminal 4 of the first normally closed contact of the second double normally closed relay DQ7; the lower end of the third load resistor R3 is connected to terminal 5 of the second normally closed contact of the second double normally closed relay DQ7.

[0014] In the first state acquisition circuit (connected to X1 and X4), one end of resistor R10 is connected to connector contact X1, and the other end is connected to the cathode of Zener diode ZD1; the anode of ZD1 is connected to the anode (pin 1) of the input diode of optocoupler OP1; one end of resistor R11 is connected to the cathode (pin 2) of the input diode of optocoupler OP1, and the other end is connected to connector contact X4. The collector (pin 4) of the output transistor of optocoupler OP1 is connected to the microcontroller's operating voltage +3.3V, and the emitter (pin 3) of the output transistor of optocoupler OP1 is connected to the microcontroller's input pin and pulled down to the microcontroller's operating reference ground GND through resistor R12. This circuit constitutes the fixed operation action signal acquisition loop.

[0015] In the second state acquisition circuit (connected to X2 and X4), one end of resistor R13 is connected to connector contact X2, and the other end is connected to the cathode of Zener diode ZD2; the anode of ZD2 is connected to the anode (pin 1) of the input diode of optocoupler OP2; one end of resistor R14 is connected to the cathode (pin 2) of the input diode of optocoupler OP2, and the other end is connected to connector contact X4. The collector (pin 4) of the output transistor of optocoupler OP2 is connected to the microcontroller's operating voltage +3.3V, and the emitter (pin 3) of the output transistor of optocoupler OP2 is connected to the microcontroller's input pin and pulled down to the microcontroller's operating reference ground GND through resistor R15. This circuit constitutes the reverse operation signal acquisition loop.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) The present invention simulates the switch machine status comprehensively, is easy to arrange and simple to operate, and can increase or decrease the number of simulation devices according to the on-site debugging needs, which significantly improves the on-site debugging efficiency of the all-electronic interlocking system.

[0018] (2) Two-way independent control: This solves the problem of single-way simulation. The two-way four-wire switch machine simulation circuit on the single board works independently. It can meet the debugging requirements of simulating 40-way switch machines by configuring two 6U-355 chassis boards, thus solving the limitation of single-way simulation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the working topology of the ZD6 four-wire switch machine in the prior art.

[0020] Figure 2 This is a schematic diagram of the main circuit principle in the four-wire switch machine simulation circuit of this embodiment.

[0021] Figure 3 This is a schematic diagram of the positioning indication circuit in this embodiment.

[0022] Figure 4 This is a schematic diagram of the inverted bit representation circuit in this embodiment.

[0023] Figure 5 This is a schematic diagram of the switch operation action acquisition circuit in this embodiment.

[0024] Figure 6 This is a schematic diagram of the turnout simulation circuit in this embodiment.

[0025] Figure 7 This is a schematic diagram of the undercurrent simulation circuit in this embodiment.

[0026] Figure 8 This is a schematic diagram of the overcurrent simulation circuit in this embodiment.

[0027] Figure 9 This is a schematic diagram of the circuit breaker simulation circuit in this embodiment. Detailed Implementation

[0028] First, to facilitate the introduction of the use and internal working principle of the portable four-wire display simulation device of the present invention, let's first outline the internal principle of the ZD6 actual four-wire switch machine. The internal topology diagram of the ZD6 four-wire switch machine in its positioning, reverse, and running states is shown below. Figure 1 As shown;

[0029] in: This represents a two-phase winding of a DC motor; X1 represents the diode inside the switch machine; X2, X3, and X4 represent the four contacts of the switch machine connector.

[0030] The following is a description of different scenarios:

[0031] The switch machine is in position: From the switch machine contacts, X2 and X4 are connected to one phase and the negative terminal of the DC motor winding, respectively; in addition, there is a diode inside the switch machine, with the conduction direction from X3 to X1.

[0032] The switch machine is in the reverse position: From the switch machine contacts, X1 and X4 are connected to one phase and the negative terminal of the DC motor winding, respectively; in addition, there is a diode inside the switch machine, with the conduction direction from X2 to X3.

[0033] The switch machine is in operation: From the switch machine contacts, X1 and X2 are connected to two phases of the DC motor respectively, and X4 is connected to the negative terminal of the motor; at this time, since X3 is floating, it is not indicated.

[0034] Next, the working principle of the novel dual-path four-wire switch machine simulation circuit of the present invention is introduced: a dual-path four-wire switch machine simulation circuit is connected to the switch machine control circuit through four contacts X1, X2, X3 and X4. The circuit includes a main circuit, a first state acquisition circuit and a second state acquisition circuit. The main circuit includes an indication circuit and a load circuit.

[0035] like Figure 2 As shown, the indicating circuit includes: a first double normally open relay DQ1, a second double normally open relay DQ2, a first single normally open relay DQ4, a second single normally open relay DQ5, and an indicating diode D1;

[0036] The load circuit includes: a first double normally closed relay DQ6, a second double normally closed relay DQ7, a first load resistor R1, a second load resistor R2, and a third load resistor R3.

[0037] The circuit indicates that terminal 3 of the first normally open contact of the first double normally open relay DQ1 is connected to terminal 3 of the first normally open contact of the second double normally open relay DQ2, and together they are connected to connector contact X3; terminal 4 of the first normally open contact of the first double normally open relay DQ1 is connected to terminal 5 of the second normally open contact of the second double normally open relay DQ2, and together they are connected to the cathode of the indicating diode D1; terminal 6 of the second normally open contact of the first double normally open relay DQ1 is connected to terminal 4 of the normally open contact of the first single normally open relay DQ4, and together they are connected to connector contact X2; terminal 5 of the second normally open contact of the first double normally open relay DQ1 is connected to terminal 4 of the first normally open contact of the second double normally open relay DQ2, and together they are connected to the anode of the indicating diode D1.

[0038] The second normally open contact 6 of the second double normally open relay DQ2 is connected to the normally open contact 3 of the second single normally open relay DQ5, and together they are connected to connector contact X1; the normally open contact 4 of the first single normally open relay DQ4 is connected to the normally open contact 4 of the second single normally open relay DQ5, and together they are connected to the upper end of the first load resistor R1 and the first normally closed contact 3 of the first double normally closed relay DQ6.

[0039] The lower end of the first load resistor R1 in the load circuit is connected to terminal 6 of the second normally closed contact of the first double normally closed relay DQ6, and together they are connected to connector contact X4; the upper end of the second load resistor R2 is connected to terminal 4 of the first normally closed contact of the first double normally closed relay DQ6, and together they are connected to terminal 3 of the first normally closed contact of the second double normally closed relay DQ7; the lower end of the second load resistor R2 is connected to terminal 5 of the second normally closed contact of the first double normally closed relay DQ6, and together they are connected to terminal 6 of the second normally closed contact of the second double normally closed relay DQ7; the upper end of the third load resistor R3 is connected to terminal 4 of the first normally closed contact of the second double normally closed relay DQ7; the lower end of the third load resistor R3 is connected to terminal 5 of the second normally closed contact of the second double normally closed relay DQ7.

[0040] The indicator circuit is used to switch between the functions of "squeezing out", "blocking", "phase loss", "fixed meter", and "reverse meter"; the status acquisition circuit, in conjunction with the load circuit, is used to simulate the "undercurrent", "overcurrent", and "rated" load states of the switch machine.

[0041] Positioning analog circuit:

[0042] like Figure 3 As shown, in the circuit, the normally open contact of the second double normally open relay DQ2 is closed. Terminal 3 of the first normally open contact of DQ2 is connected to connector contact X3, and terminal 4 of the first normally open contact of DQ2 is connected to the anode of diode D1. Terminal 6 of the second normally open contact of DQ2 is connected to connector contact X1, and terminal 5 of the second normally open contact of DQ2 is connected to the cathode of diode D1. One end of the first load resistor R1 is connected to connector contact X4, and the other end is left floating. Connector contact X2 is not connected to any components on this board.

[0043] When the circuit implements the "positioning indication" function, the microcontroller will drive relay DQ2 (normally open contact closes), such as... Figure 3 As shown, the diode's conduction direction switches from X3 to X1, while X2 remains floating, and X4's connection to one end of the load resistor remains unchanged. This state is equivalent to the positioning of a real switch machine.

[0044] Inverted analog circuit:

[0045] like Figure 4 As shown, in the circuit, the normally open contact of the first double normally open relay DQ1 is closed. Terminal 3 of the first normally open contact of DQ1 is connected to connector contact X3, and terminal 4 of the first normally open contact of DQ1 is connected to the cathode of diode D1. Terminal 6 of the second normally open contact of DQ1 is connected to connector contact X2, and terminal 5 of the second normally open contact of DQ2 is connected to the anode of diode D1. One end of the first load resistor R1 is connected to connector contact X4, and the other end is left floating. Connector contact X1 is not connected to any components on this board.

[0046] When the circuit implements the "reverse bit indication" function, the microcontroller will drive relay DQ1 (normally open contact closes), such as... Figure 4 As shown, the diode's conduction direction switches from X2 to X3, while X1 remains floating, and X4's connection to one end of the load resistor remains unchanged. This state is equivalent to the reverse position of a real switch machine.

[0047] Switch signal recognition circuit:

[0048] like Figure 5As shown, in the first state acquisition circuit (connected to X1 and X4), one end of resistor R10 is connected to connector contact X1, and the other end is connected to the cathode of Zener diode ZD1; the anode of ZD1 is connected to the anode (pin 1) of the input diode of optocoupler OP1; one end of resistor R11 is connected to the cathode (pin 2) of the input diode of optocoupler OP1, and the other end is connected to connector contact X4. The collector (pin 4) of the output transistor of optocoupler OP1 is connected to the microcontroller's operating voltage +3.3V, and the emitter (pin 3) of the output transistor of optocoupler OP1 is connected to the microcontroller's input pin and pulled down to the microcontroller's operating reference ground GND through resistor R12. This circuit constitutes the fixed operation action signal acquisition loop.

[0049] like Figure 5 As shown, in the second state acquisition circuit (connected to X2 and X4), one end of resistor R13 is connected to connector contact X2, and the other end is connected to the cathode of Zener diode ZD2; the anode of ZD2 is connected to the anode (pin 1) of the input diode of optocoupler OP2; one end of resistor R14 is connected to the cathode (pin 2) of the input diode of optocoupler OP2, and the other end is connected to connector contact X4. The collector (pin 4) of the output transistor of optocoupler OP2 is connected to the microcontroller's operating voltage +3.3V, and the emitter (pin 3) of the output transistor of optocoupler OP2 is connected to the microcontroller's input pin and pulled down to the microcontroller's operating reference ground GND through resistor R15. This circuit constitutes the reverse operation signal acquisition loop.

[0050] When the four-wire turnout board is in operation, X1 and X4 have +220VDC and 0V voltages respectively. After being converted by the optocoupler isolation circuit, these voltages are supplied to the microcontroller at a high level (e.g., ...). Figure 5 As shown, DC_Fb=1), at this time, since X2 has no voltage, it is given a low level to the microcontroller after passing through the optocoupler isolation circuit (e.g., Figure 5 As shown, FC_Fb=0). The microcontroller determines the operation as fixed based on the signals DC_Fb=1 and FC_Fb=0.

[0051] When the four-wire turnout board is reversed, X2 and X4 have +220VDC and 0V voltages respectively. After passing through the optocoupler isolation circuit, these voltages are supplied to the microcontroller at a high level (e.g., ...). Figure 5 As shown, FC_Fb=1), at this time, since X1 has no voltage, it is given a low level to the microcontroller after passing through the optocoupler isolation circuit (e.g., Figure 5 As shown, DC_Fb=0). The microcontroller determines reverse operation based on the DC_Fb=0 and FC_Fb=1 signals.

[0052] Simulation circuit for switching and derailment:

[0053] like Figure 6As shown, terminal X3 in the circuit is left unconnected; the normally open contact of the first single normally open relay DQ4 in the load circuit is closed, and terminal 3 of the closed contact of DQ4 is connected to connector contact X2; the normally open contact of the second single normally open relay DQ5 in the load circuit is closed, and terminal 3 of the closed contact of DQ5 is connected to connector contact X1.

[0054] like Figure 6 As shown, in the load circuit, terminal 4 of the closed contact of the first single normally open relay DQ4, terminal 4 of the closed contact of the second single normally open relay DQ5, and terminal 3 of the first normally closed contact of the first double normally closed relay DQ6 are simultaneously connected to the upper end of the first load resistor R1. The lower end of R1 is connected to terminal 6 of the second normally closed contact of DQ6, and together they are connected to connector contact X4. The two ends of the second load resistor R2 are respectively connected to terminals 4 and 5 of the two sets of normally closed contacts of DQ6.

[0055] When the four-wire simulation board is in the "positioning" simulation state, if reverse operation of the four-wire turnout is detected, the microcontroller will drive relays DQ4 and DQ5 (normally open contacts close), and the four-wire turnout simulation board will switch to the turnout operation state (turnout operation current 1.2A, such as...). Figure 6 As shown), the time for the switch to reach its position is set by the host computer, with a default of 2 seconds (if a squeeze is simulated, the switch operation time follows the "squeeze" switch status); if a fixed operation is detected, this simulation board will not operate.

[0056] When the four-wire simulation board is in the "reverse" simulation state, if the four-wire turnout board is detected to be in operation, the microcontroller will drive relays DQ4 and DQ5 (normally open contacts close), and the four-wire turnout simulation board will switch to the turnout operation state (turnout operation current 1.2A, such as...). Figure 6 As shown), the time for the switch to reach its position is set by the host computer, with a default of 2 seconds (if a squeeze is simulated, the switch operation time follows the "squeeze" switch status); if reverse operation is detected, this simulation board will not operate.

[0057] Undercurrent simulation circuit:

[0058] like Figure 7 As shown, terminal X3 in the circuit is left floating; the normally open contact of the first single normally open relay DQ4 in the load circuit is closed, and terminal 3 of the closed contact of DQ4 is connected to connector contact X2; the normally open contact of the second single normally open relay DQ5 in the load circuit is closed, and terminal 3 of the closed contact of DQ5 is connected to connector contact X1. One end of the first load resistor R1 is connected to terminal 4 of the closed contacts of DQ4 and DQ5, and the other end is connected to connector contact X4.

[0059] When the panel toggle switch is set to the right for "undercurrent," the microcontroller will drive the first double normally closed relay DQ6 (normally closed contacts open). If a four-wire turnout operation is detected at this time, the microcontroller will drive relays DQ4 and DQ5 (normally open contacts close), and the four-wire turnout simulation board will switch to undercurrent operation mode (operation current 0.2A, such as...). Figure 7 (As shown).

[0060] Overcurrent state simulation circuit:

[0061] like Figure 8 As shown, terminal X3 in the circuit is left unconnected; the normally open contact of the first single normally open relay DQ4 in the load circuit is closed, and terminal 3 of the closed contact of DQ4 is connected to connector contact X2; the normally open contact of the second single normally open relay DQ5 in the load circuit is closed, and terminal 3 of the closed contact of DQ5 is connected to connector contact X1.

[0062] like Figure 8 As shown, in the load circuit, terminal 4 of the closed contact of the first single normally open relay DQ4, terminal 4 of the closed contact of the second single normally open relay DQ5, and terminal 3 of the first normally closed contact of the first double normally closed relay DQ6 are simultaneously connected to the upper end of the first load resistor R1. The lower end of R1 is connected to terminal 6 of the second normally closed contact of DQ6, and together they are connected to connector contact X4. The two ends of the second load resistor R2 are respectively connected to terminals 4 and 5 of the two sets of normally closed contacts of DQ6. Terminals 4 and 5 of the two sets of normally closed contacts of DQ6 are respectively connected to terminals 3 and 6 of the two sets of normally closed contacts of the second double normally closed relay DQ7. The two ends of the third load resistor R3 are respectively connected to terminals 4 and 5 of the two sets of normally closed contacts of DQ7.

[0063] When the panel toggle switch is set to the right for "overcurrent," the microcontroller will not drive relays DQ6 and DQ7 (normally closed, remaining closed). If a four-wire turnout operation is detected at this time, the microcontroller will drive relays DQ4 and DQ5 (normally open contacts close), and the four-wire turnout simulation board will switch to overcurrent operation mode (operation current 11.3A, such as...). Figure 8 (As shown).

[0064] Open circuit simulation circuit:

[0065] like Figure 9 As shown, terminals X1, X2, and X3 in the circuit are left unconnected; one end of the first load resistor R1 is connected to contact X4, and the other end is left unconnected.

[0066] When the panel toggle switch is turned to the right ("off circuit"), the microcontroller will control all relays to be in the off-circuit state, resulting in the following circuit: Figure 9 As shown.

[0067] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-channel four-wire switch machine analog circuit, characterized in that: The circuit is connected to the switch machine control circuit via the X1, X2, X3 and X4 contacts of a 4-pin connector. The circuit includes an indication circuit and a load circuit. The indication circuit includes: a first double normally open relay DQ1, a second double normally open relay DQ2, a first single normally open relay DQ4, a second single normally open relay DQ5, and an indication diode D1; Specifically, terminal 3 of the first normally open contact of the first double normally open relay DQ1 is connected to terminal 3 of the first normally open contact of the second double normally open relay DQ2, and together they are connected to connector contact X3; terminal 4 of the first normally open contact of the first double normally open relay DQ1 is connected to terminal 5 of the second normally open contact of the second double normally open relay DQ2, and together they are connected to the cathode representing diode D1; terminal 6 of the second normally open contact of the first double normally open relay DQ1 is connected to terminal 4 of the normally open contact of the first single normally open relay DQ4, and together they are connected to connector contact X2; terminal 5 of the second normally open contact of the first double normally open relay DQ1 is connected to terminal 4 of the first normally open contact of the second double normally open relay DQ2, and together they are connected to the anode representing diode D1. The 6th terminal of the second normally open contact of the second double normally open relay DQ2 is connected to the 3rd terminal of the normally open contact of the second single normally open relay DQ5, and together they are connected to connector contact X1; the 4th terminal of the normally open contact of the first single normally open relay DQ4 is connected to the 4th terminal of the normally open contact of the second single normally open relay DQ5, and together they are connected to the upper end of the first load resistor R1 and the 3rd terminal of the first normally closed contact of the first double normally closed relay DQ6. The load circuit includes: a first double normally closed relay DQ6, a second double normally closed relay DQ7, a first load resistor R1, a second load resistor R2, and a third load resistor R3; The lower end of the first load resistor R1 is connected to terminal 6 of the second normally closed contact of the first double normally closed relay DQ6, and together they are connected to connector contact X4; the upper end of the second load resistor R2 is connected to terminal 4 of the first normally closed contact of the first double normally closed relay DQ6, and together they are connected to terminal 3 of the first normally closed contact of the second double normally closed relay DQ7; the lower end of the second load resistor R2 is connected to terminal 5 of the second normally closed contact of the first double normally closed relay DQ6, and together they are connected to terminal 6 of the second normally closed contact of the second double normally closed relay DQ7; the upper end of the third load resistor R3 is connected to terminal 4 of the first normally closed contact of the second double normally closed relay DQ7; the lower end of the third load resistor R3 is connected to terminal 5 of the second normally closed contact of the second double normally closed relay DQ7.

2. The dual-channel four-wire switch machine analog circuit according to claim 1, characterized in that: The circuit also includes a first state acquisition circuit and a second state acquisition circuit. The first state acquisition circuit includes: resistor R10, resistor R11, resistor R12, optocoupler OP1, and Zener diode ZD1; Among them, one end of resistor R10 is connected to connector contact X1, and the other end is connected to the cathode of Zener diode ZD1; the anode of Zener diode ZD1 is connected to the anode of input diode of optocoupler OP1; one end of resistor R11 is connected to the cathode of input diode of optocoupler OP1, and the other end is connected to connector contact X4; the collector of output transistor of optocoupler OP1 is connected to the microcontroller's operating voltage +3.3V, and the emitter of output transistor of optocoupler OP1 is connected to the microcontroller's input pin and pulled down to the microcontroller's operating reference ground GND through resistor R12; The second state acquisition circuit includes: resistors R13, R14, and R15, optocoupler OP2, and Zener diode ZD2; Among them, one end of resistor R13 is connected to connector contact X2, and the other end is connected to the cathode of Zener diode ZD2; the anode of Zener diode ZD2 is connected to the anode of input diode of optocoupler OP2; one end of resistor R14 is connected to the cathode of input diode of optocoupler OP2, and the other end is connected to connector contact X4; the collector of output transistor of optocoupler OP2 is connected to the microcontroller's operating voltage +3.3V, and the emitter of output transistor of optocoupler OP2 is connected to the microcontroller's input pin, and pulled down to the microcontroller's operating reference ground GND through resistor R15.

3. The dual-channel four-wire switch machine analog circuit according to claim 1, characterized in that: The first load resistor R1 alone provides 0.2A of current; the first load resistor R1 and the second load resistor R2 together provide 1.2A of current; the first load resistor R1, the second load resistor R2 and the third load resistor R3 together provide 11.3A of current.

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