Emergency signal state detection method of subway automatic ticket checker

Abstract

The invention relates to a state detection method for emergency signals of an automatic subway ticket checker. A state detection system circuit and an automatic ticket checker unit load circuit which are electrically connected are included. The state detection system circuit comprises an MCU and a peripheral circuit electrically connected with the MCU. The peripheral circuit comprises an input detection circuit, a current detection amplification circuit, a standby power supply control circuit, a state indication circuit and a current detection resistor which are electrically connected with the MCU; the MCU is provided with an ADC pin and a GPIO pin; the device is reasonable in design, compact in structure and convenient to use.

Description

Technical Field

[0001] The invention relates to a state detection method for an emergency signal of a subway automatic ticket checking machine, and is applied to a subway AFC (Automatic Fare Collection; automatic ticket vending and checking system) automatic ticket checking machine. Background Art

[0002] Currently, there is no status detection system designed for ATM emergency signals. The status of ATMs can only be confirmed through manual inspections or on-site problem reporting. Manual inspections are labor-intensive and require testing every ATM, which is inefficient. When on-site staff discover and report an ATM malfunction during use, maintenance personnel must conduct on-site inspections to determine the cause and repair the problem, disrupting normal traffic flow.

[0003] To address these shortcomings, a system for detecting open and short circuits in the emergency signal of automatic ticket gates has been designed. This system can confirm the current status of the automatic ticket gate by monitoring the status of the emergency signal interface circuit in real time. This significantly reduces the frequency of manual inspections and saves costs. It can also promptly locate abnormal automatic ticket gates and identify the cause of the abnormality, improving the efficiency of repairing abnormal automatic ticket gates.

[0004] The system also incorporates an input detection circuit and a backup power supply control circuit to detect the external input voltage and determine whether the backup power supply needs to be activated. If the external input voltage is detected to be disconnected, the MCU activates the backup power supply through the backup power supply control circuit, ensuring stable operation of the system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is generally to provide a method for detecting the state of an emergency signal of an automatic ticket checking machine in a subway.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is:

[0007] A subway automatic ticket checking machine based on emergency signal status detection comprises an electrically connected status detection system circuit and an automatic ticket checking machine group load circuit;

[0008] The state detection system circuit includes an MCU and a peripheral circuit electrically connected to the MCU;

[0009] The peripheral circuit includes an input detection circuit electrically connected to the MCU, a current detection amplifier circuit, a backup power supply control circuit, a status indication circuit and a current detection resistor;

[0010] MCU has ADC pin and GPIO pin;

[0011] The ADC pin is connected to the current detection amplifier circuit;

[0012] The current detection amplifier circuit includes chip U1; in chip U1, pin 6 is connected to the ADC pin, pins 1 and 2 are grounded, pin 3 is connected to VCC1, and bridge A composed of resistors R2-4 and capacitor C1 is connected between pins 4 and 5; after VCC3 passes through diode D1, it is divided into three paths, one path is connected to the node of resistors R2 and R3 of bridge A, the other path passes through current detection resistor R1, and is respectively connected to the node of resistors R2 and R4 and then passes through current limiting resistor R15 to connect to the load circuit of the automatic ticket checking machine; three paths are connected to the backup power supply control circuit.

[0013] As a further improvement of the above technical solution:

[0014] Wherein, a GPIO pin is electrically connected to a status indication circuit;

[0015] The status indication circuit includes a resistor R6 and an LED light electrically connected to the GPIO pin.

[0016] The backup power supply control circuit includes a transistor Q1 and a MOS transistor Q2 whose gate is electrically connected to the collector of the transistor Q1;

[0017] One GPIO pin of the MCU is connected to the base of transistor Q1 through a series diode D2 and a resistor R7;

[0018] There is a resistor R10 between the base and emitter of transistor Q1; the emitter is grounded;

[0019] The drain of MOS tube Q2 is connected to the node of resistors R2 and R3 through diode D3; the node of resistors R2 and R3 is grounded through resistor R11;

[0020] VCC3 is directly connected to the source of MOS tube Q2 and connected to the gate of MOS tube Q2 through resistor R8;

[0021] There is a resistor R9 between the gate of MOS tube Q2 and the collector of transistor Q1;

[0022] A current limiting resistor R15 is connected in series to the circuit where the current detection resistor R1 is connected to the load circuit of the automatic ticket checking machine.

[0023] The current detection amplifier circuit includes chip U2C and optocoupler;

[0024] Pin 4 of the optocoupler is grounded through resistor R14, and pins 5 and 7 are grounded; VCC3 is connected to pins 2 and 3 respectively through reverse-connected diodes D4 and D5; VCC2 is connected to pins 1, 6 and 8 respectively through resistors R12 and R13; pins 6 and 8 are connected to the input pin 5 of the chip U2C, and pin 6 of U2C is connected to the GPIO pin of the MCU.

[0025] The load circuit of the automatic ticket checking machine includes a terminal resistor R24 and several emergency signal interface circuits arranged in parallel;

[0026] Among them, the emergency signal interface circuit AG9 includes transistor Q9A and relay RELAY9;

[0027] The emitter of transistor Q9A and one end of resistor R24 are grounded respectively, and the base is connected to the current detection amplifier circuit through resistor R22 and the other end of resistor R24; the base is grounded through resistor R23; and the collector is connected to the control coil of relay RELAY9.

[0028] The current detection resistor R1 is between the bus power supply VCC3 and the automatic ticket inspection machine load.

[0029] When current flows from the bus power supply to the automatic ticket inspection machine load through the current detection resistor R1, a voltage difference exists across the current detection resistor R1. The voltage difference is respectively sent to the IN+ and IN- input terminals of the chip U1, and the chip U1 amplifies and outputs the voltage difference.

[0030] The automatic ticket checking machine load circuit can be connected to a maximum of ten groups.

[0031] A method for detecting the state of an emergency signal of an automatic ticket gate of a subway includes the above-mentioned automatic ticket gate of the subway; the method comprises the following steps:

[0032] S1, calculates the minimum voltage reference value Vmin and the maximum voltage reference value Vmax under normal conditions according to the resistance of the external load;

[0033] S2, after the system starts, the MCU checks the input voltage of the input detection circuit to confirm whether the external input voltage exists;

[0034] If the external voltage exists, the AD detection of the MCU is directly turned on to detect the status of the external automatic ticket gate in real time;

[0035] If the external voltage does not exist, the backup power control circuit is started through the GPIO pin of the MCU, the backup power is used as the input voltage to power the system, and then the AD detection of the MCU is turned on;

[0036] S3, through the current detection amplifier circuit, amplifies the voltage difference between the two ends of the current detection resistor, and sends the amplified voltage difference to the AD pin of the MCU for real-time detection and analysis of the voltage difference;

[0037] S4, the MCU compares the obtained voltage value with the reference values Vmin and Vmax to determine whether the current state of the automatic ticket checking machine is normal.

[0038] As a further improvement of the above technical solution:

[0039] If the detection value is less than Vmin, the automatic ticket gate is considered to be in a circuit-breaking state;

[0040] If the detection value is greater than Vmax, the automatic ticket gate is considered to be in a short-circuit state;

[0041] If the detection value is between Vmin and Vmax, the current state of the automatic ticket gate is considered normal;

[0042] S5, if the automatic ticket gate is in normal state, the MCU control state indication circuit is in state 1; if it is in short circuit state, the MCU control state indication circuit is in state 2;

[0043] If it is in the open circuit state, the MCU control status indication circuit is in state 3;

[0044] MCU uploads status 1, 2 or 3;

[0045] Status 1, 2 or 3 uses lights and / or sounds.

[0046] Since the value of the current detection resistor R1 is much smaller than the current limiting resistor R15, when ten automatic ticket checking machines are connected in parallel, the current value is:

[0047] I N =Vcc / (current limiting resistor R 15 +R AG1 / / R AG2 / / … / / R AG9 / / R 24 );

[0048] When the automatic ticket gate is short-circuited, the current is:

[0049] I S =Vcc / current limiting resistor R 15 ;

[0050] When all 10 automatic ticket checking machines are disconnected, the current value is 0;

[0051] When only the last of 10 automatic ticket gates is working properly and the other 9 are disconnected, the current is:

[0052] I O9 =Vcc / (current limiting resistor R 15 +R 24 );

[0053] The current value I of the automatic ticket gate load under normal conditions N In I S and I O9 between;

[0054] When the detected current value is less than I O9 When the detected current value is greater than or equal to I S When , it is determined that the load of the automatic ticket gate is in a short-circuit state.

[0055] This system utilizes current amplification technology and analog-to-digital (A / D) conversion principles. A current amplifier amplifies tiny current signals and converts them into an analog voltage output. This output analog voltage signal passes through the A / D converter of the microcontroller unit (MCU), where it is converted into a digital voltage signal. This value is then compared with a reference value to determine whether the ATM is in an abnormal state (open or short circuits are considered abnormal states). Warnings, such as light and sound, are then emitted in response to abnormal conditions.

[0056] The basic principle of current sense amplifiers is to place a current sense resistor in the detection circuit between the bus power supply and the load. When current flows from the bus power supply through the current sense resistor to the load, a voltage difference appears across the resistor. The voltage across the resistor is fed into the two inputs of the current sense amplifier, where the voltage difference is detected and amplified. This amplified voltage difference is then output through the output pin of the current sense amplifier, completing the process of converting the current value into a voltage value and amplifying the output.

[0057] Signals in circuits all exist as analog signals, which are continuous in time. Therefore, continuous signals need to be discretized into digital signals. This is done by sampling the input analog signal at a series of selected instants and then converting these sampled values into digital output values. Therefore, the AD conversion process begins by sampling the input analog voltage signal. After sampling, a hold time begins, during which the sampled analog value is converted into a digital value and the conversion result is encoded in a specific format. The next sampling cycle then begins.

[0058] The automatic ticket gate's emergency signal interface circuit is connected to the system's load side. Changes on the load side cause changes in the system's current, which in turn causes changes in the voltage difference between the two input terminals of the current sense amplifier, which in turn causes changes in the output voltage. Therefore, this system compares the voltage difference between the load side and the bus voltage side of the sense resistor to determine whether the automatic ticket gate on the load side is experiencing abnormal conditions such as open circuits or short circuits.

[0059] The invention has reasonable design, low cost, durability, safety and reliability, simple operation, time and labor saving, money saving, compact structure and convenient use. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a schematic diagram of the overall workflow of the system of the present invention.

[0061] Figure 2 It is a schematic diagram of the state judgment part of the present invention.

[0062] Figure 3 It is a block diagram of the overall circuit of the present invention.

[0063] Figure 4 It is a circuit diagram of the status detection system of the present invention.

[0064] Figure 5 It is a schematic diagram of an automatic ticket checking machine of the present invention. DETAILED DESCRIPTION

[0065] like Figure 1-Figure 5 As shown, Figure 3 The unclearness does not affect the scope of protection of the present invention. The working process of the system is described as follows:

[0066] S1, calculates the minimum voltage reference value Vmin and the maximum voltage reference value Vmax under normal conditions according to the resistance of the external load;

[0067] S2. After the system is started, the MCU checks the input voltage of the input detection circuit to confirm whether the external input voltage exists. If the external voltage exists, the AD detection is directly turned on to detect the status of the external automatic ticket checking machine in real time. If the external voltage does not exist, the backup power supply control circuit is started through the GPIO (General-Purpose Input / Output) pin, and the backup power supply is used as the input voltage to power the system, and then the AD detection is turned on.

[0068] S3, through the current detection amplifier circuit, amplifies the voltage difference flowing through the two ends of the current detection resistor, and sends the amplified voltage difference to the AD pin of the MCU for real-time detection and analysis of the voltage difference;

[0069] In step S4, the MCU compares the obtained voltage value with the reference values Vmin and Vmax to determine whether the current state of the automatic ticket gate is normal: if the detected value is less than Vmin, the automatic ticket gate is considered to be in an open circuit state; if the detected value is greater than Vmax, the automatic ticket gate is considered to be in a short circuit state; if the detected value is between Vmin and Vmax, the automatic ticket gate is considered to be in a normal state;

[0070] In step S5, if the automatic ticket gate is in normal state, the MCU controls the status indication circuit to be in state 1; if it is in short circuit state, the MCU controls the status indication circuit to be in state 2; if it is in open circuit state, the MCU controls the status indication circuit to be in state 3, thereby informing the staff of the current state of the automatic ticket gate. (States 1 to 3 can be a combination of various lights and sound signals, which can be determined according to user needs)

[0071] like Figure 3-5 As shown in the figure, the system includes two parts: an electrically connected status detection system circuit and an automatic ticket checking machine group load circuit; wherein AGx represents an automatic ticket checking machine Automatic Gate, which is electrically connected to 10.

[0072] The status detection system circuit includes an electrically connected input detection circuit, a current detection amplifier circuit, a backup power supply control circuit, a status indication circuit, a current detection resistor, a current limiting resistor and other peripheral circuits and an MCU.

[0073] MCU has ADC pin and GPIO pin;

[0074] Wherein, a GPIO pin is electrically connected to a status indication circuit;

[0075] The ADC pin is connected to the current detection amplifier circuit:

[0076] The current detection amplifier circuit includes chip U1; in chip U1, pin 6 is connected to the ADC pin, pins 1 and 2 are grounded, pin 3 is connected to VCC1, and bridge A composed of resistors R2-4 and capacitor C1 is connected between pins 4 and 5; after VCC3 passes through diode D1, it is divided into three paths, one path is connected to the node of resistors R2 and R3 of bridge A, the other path passes through current detection resistor R1, and is respectively connected to the node of resistors R2 and R4 and then passes through current limiting resistor R15 to connect to the load circuit of the automatic ticket checking machine; three paths are connected to the backup power supply control circuit.

[0077] The backup power supply control circuit includes a transistor Q1 and a MOS transistor Q2 whose gate is electrically connected to the collector of the transistor Q1;

[0078] One GPIO pin of the MCU is connected to the base of transistor Q1 through a series diode D2 and a resistor R7;

[0079] There is a resistor R10 between the base and emitter of transistor Q1; the emitter is grounded;

[0080] The drain of MOS tube Q2 is connected to the node of resistors R2 and R3 through diode D3; the node of resistors R2 and R3 is grounded through resistor R11;

[0081] VCC3 is directly connected to the source of MOS tube Q2 and connected to the gate of MOS tube Q2 through resistor R8;

[0082] There is a resistor R9 between the gate of MOS tube Q2 and the collector of transistor Q1;

[0083] A current limiting resistor R15 is connected in series to the circuit where the current detection resistor R1 is connected to the load circuit of the automatic ticket checking machine;

[0084] The current detection amplifier circuit includes chip U2C and optocoupler;

[0085] Pin 4 of the optocoupler is grounded through resistor R14, and pins 5 and 7 are grounded; VCC3 is connected to pins 2 and 3 respectively through reverse-connected diodes D4 and D5; VCC2 is connected to pins 1, 6 and 8 respectively through resistors R12 and R13; pins 6 and 8 are connected to the input pin 5 of the chip U2C, and pin 6 of U2C is connected to the GPIO pin of the MCU.

[0086] The primary component of the automatic ticket gate load circuit is the emergency signal interface circuit. The status detection system circuit is connected to the automatic ticket gate's emergency signal interface circuit via a current-limiting resistor. The system determines the status of the automatic ticket gate by determining the status of the emergency signal interface circuit. A single status detection system can connect up to 10 automatic ticket gates to form an automatic ticket gate group. A terminating resistor is connected in series with the last automatic ticket gate to serve as a detection resistor.

[0087] The load circuit of the automatic ticket checking machine includes a terminal resistor R24 and several emergency signal interface circuits arranged in parallel;

[0088] Among them, the emergency signal interface circuit AG9 includes transistor Q9A and relay RELAY9;

[0089] The emitter of transistor Q9A and one end of resistor R24 are grounded respectively, and the base is connected to the current detection amplifier circuit through resistor R22 and the other end of resistor R24; the base is grounded through resistor R23; and the collector is connected to the control coil of relay RELAY9;

[0090] The working principle of the present invention is combined with Figure 1 、 Figure 2 and Figure 3 , the system works as follows:

[0091] After the system is powered on, the MCU, as the core of the system, first detects whether the external input voltage exists through the "input detection circuit". Only when the external input voltage exists can the current detection amplifier circuit work normally;

[0092] If it is detected that there is no external voltage input, the MCU will turn on the backup voltage to power the system by controlling the GPIO pin connected to the "backup power control circuit" and at the same time turn on the AD detection function.

[0093] A current sensing resistor, R1 (hereafter referred to as R1), is placed between the bus power supply (input voltage / backup voltage) and the ATM load. When current flows from the bus power supply through R1 to the ATM load, a voltage difference appears across the resistor. The measured value across R1 is fed into the IN+ and IN- inputs of the current sensing amplifier circuit, where the voltage difference is detected and amplified. This amplified voltage difference is then output through the OUT pin of the current sensing amplifier circuit, completing the process of converting the current value into a voltage and amplifying the output.

[0094] The "current detection amplifier circuit" detects the voltage difference between the two ends of R1, amplifies the value, and inputs it to the AD pin of the MCU through the OUT pin. The MCU compares the data value detected by the AD pin with the calculated reference values Vmin and Vmax to determine whether the current automatic ticket gate is in a normal state, and displays the current state of the automatic ticket gate by controlling the "status indication circuit".

[0095] The automatic ticket gate unit acts as an external load, connected between R1 and R4 via a current-limiting resistor R15 (hereinafter referred to as R15). The value of R1 is much smaller than that of R15. A single automatic ticket gate unit can connect up to 10 automatic ticket gates. The last automatic ticket gate unit has a terminal resistor R24 (hereinafter referred to as R24) connected in series to serve as a detection resistor.

[0096] Take 10 external automatic ticket gates as an example. When all 10 automatic ticket gates are in normal operation, the current value is:

[0097] I N =Vcc / (R 15 +R AG1 / / R AG2 / / … / / R AG9 / / R 24 );

[0098] When the automatic ticket gate is short-circuited, the current is:

[0099] I S =Vcc / R 15 :

[0100] When all 10 automatic ticket checking machines are disconnected, the current value is 0;

[0101] When only the last of 10 automatic ticket gates is working properly and the other 9 are disconnected, the current is:

[0102] I O9 =Vcc / (R 15 +R 24 );

[0103] The current value I of the automatic ticket gate load under normal conditions N In I S and I O9 between;

[0104] The number of external automatic ticket gates can be between 1 and 10, so the current value of the automatic ticket gate load under normal conditions is I N In I S and I O9 When the detected current value is less than I O9 When the detected current value is greater than or equal to I S When , it is determined that the load of the automatic ticket gate is in a short-circuit state.

[0105] In summary, the different states of the external automatic ticket checking machine can be converted into different current values in the circuit, which can be further converted into different voltage values through the current detection amplifier circuit for judgment.

[0106] The present invention uses a current detection amplifier circuit to convert changes in load current into voltage changes, and the voltage change value is detected by the MCU. The present invention uses an input detection circuit to detect the presence of an external input voltage. If not, the backup power supply is activated, thereby ensuring the stability and continuity of the detection state. The present invention uses the MCU to compare the detected voltage value with reference values Vmin and Vmax to confirm the real-time status of the external automatic ticket checking unit. The present invention uses a status indicator circuit to display the real-time status of the external automatic ticket checking unit's emergency signal.

[0107] The present invention is fully described for a clearer disclosure, and the prior art is not listed one by one.

[0108] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may be modified or some of the technical features thereof may be replaced with equivalents. It is obvious for those skilled in the art to combine multiple technical solutions of the present invention. However, these modifications or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any technical content not fully described in this invention is well-known technology.

Claims

1. A method for detecting the state of an emergency signal of an automatic ticket gate in a subway, characterized in that: Based on the subway automatic ticket machine; method The following steps are included: S1, calculates the minimum voltage reference value Vmin and the maximum voltage reference value Vmax under normal conditions according to the resistance of the external load; S2, after the system starts, the MCU checks the input voltage of the input detection circuit to confirm whether the external input voltage exists; If the external voltage exists, the AD detection of the MCU is directly turned on to detect the status of the external automatic ticket gate in real time; If the external voltage does not exist, the backup power control circuit is started through the GPIO pin of the MCU, the backup power is used as the input voltage to power the system, and then the AD detection of the MCU is turned on; S3, through the current detection amplifier circuit, amplifies the voltage difference between the two ends of the current detection resistor, and sends the amplified voltage difference to the AD pin of the MCU for real-time detection and analysis of the voltage difference; S4, the MCU compares the obtained voltage value with the reference values Vmin and Vmax to determine whether the current state of the automatic ticket checking machine is normal.

2. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 1, characterized in that: In step S4, if the detection value is less than Vmin, it is considered that the automatic ticket checking machine is in a circuit-breaking state; If the detection value is greater than Vmax, the automatic ticket gate is considered to be in a short-circuit state; If the detection value is between Vmin and Vmax, the current state of the automatic ticket gate is considered normal; S5, if the automatic ticket gate is in normal state, the MCU control state indication circuit is in state 1; if it is in short circuit state, the MCU control state indication circuit is in state 2; If it is in the open circuit state, the MCU control status indication circuit is in state 3; MCU uploads status 1, 2 or 3; Status 1, 2 or 3 uses lights and / or sounds.

3. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 1, wherein: The value of the current detection resistor R1 is less than the value of the current limiting resistor R15. When ten automatic ticket checking machines are connected in parallel, the current value is: I N =Vcc / (R 15 +R AG1 / / R AG2 / / … / / R AG9 / / R 24 ); When the automatic ticket gate is short-circuited, the current is: I S =Vcc / R 15 ; When all 10 automatic ticket checking machines are disconnected, the current value is 0; When only the last of 10 automatic ticket gates is working properly and the other 9 are disconnected, the current is: I O9 =Vcc / (R 15 +R 24 ); The current value I of the automatic ticket gate load under normal conditions N In I S and I O9 between; When the detected current value is less than I O9 When the detected current value is greater than or equal to I S When , it is determined that the automatic ticket checking machine load is in a short circuit state.

4. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 1, wherein: The subway automatic ticket checking machine includes an electrically connected state detection system circuit and an automatic ticket checking machine unit load circuit; The state detection system circuit includes an MCU and a peripheral circuit electrically connected to the MCU; The peripheral circuit includes an input detection circuit electrically connected to the MCU, a current detection amplifier circuit, a backup power supply control circuit, a status indication circuit and a current detection resistor; MCU has ADC pin and GPIO pin; The ADC pin is electrically connected to the current detection amplifier circuit.

5. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 4, characterized in that: The current detection amplifier circuit includes a chip U1. In chip U1, pin 6 is connected to the ADC pin, pins 1 and 2 are grounded, pin 3 is connected to VCC1, and a bridge A consisting of resistors R2-4 and capacitor C1 is connected between pins 4 and 5. After passing through diode D1, VCC3 is divided into three paths. One path is connected to the node of resistor R2 and resistor R3 of bridge A. The second path passes through current detection resistor R1 and is respectively connected to the node of resistor R2 and resistor R4, and then passes through current limiting resistor R15 to connect to the load circuit of the automatic ticket checking machine; the third path is connected to the backup power supply control circuit.

6. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 5, wherein: in, A GPIO pin electrical connection status indication circuit; The status indication circuit includes a resistor R6 and an LED light electrically connected to the GPIO pin.

7. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 5, wherein: The backup power supply control circuit includes a transistor Q1 and a MOS transistor Q2 whose gate is electrically connected to the collector of the transistor Q1; One GPIO pin of the MCU is connected to the base of transistor Q1 through a series diode D2 and a resistor R7; There is a resistor R10 between the base and emitter of transistor Q1; the emitter is grounded; The drain of MOS tube Q2 is connected to the node of resistors R2 and R3 through diode D3; the node of resistors R2 and R3 is grounded through resistor R11; VCC3 is directly connected to the source of MOS tube Q2 and connected to the gate of MOS tube Q2 through resistor R8; There is a resistor R9 between the gate of MOS tube Q2 and the collector of transistor Q1; A current limiting resistor R15 is connected in series to the circuit where the current detection resistor R1 is connected to the load circuit of the automatic ticket checking machine.

8. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 5, wherein: The current detection amplifier circuit includes chip U2C and optocoupler; Pin 4 of the optocoupler is connected to ground through resistor R14, and pins 5 and 7 are grounded; VCC3 is connected to pins 2 and 3 through reverse-connected diodes D4 and D5 respectively; VCC2 is connected to pin 1, pin 8 and pin 6 of the optocoupler through resistors R12 and R13 respectively; pin 8 and pin 6 of the optocoupler are connected to the input pin 5 of the chip U2C, and pin 6 of the chip U2C is connected to the GPIO pin of the MCU.

9. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 8, characterized in that: The load circuit of the automatic ticket checking machine includes a terminal resistor R24 and several emergency signal interface circuits arranged in parallel; Among them, the emergency signal interface circuit AG9 includes a transistor Q9A and a relay RELAY9; The emitter of transistor Q9A and one end of resistor R24 are grounded respectively, and the base is connected to the current detection amplifier circuit through resistor R22 and the other end of resistor R24; the base is grounded through resistor R23; and the collector is connected to the control coil of relay RELAY9.

10. The method for detecting the state of an emergency signal of an automatic ticket gate in a subway according to claim 9, wherein: The current detection resistor R1 is between the bus power supply VCC3 and the automatic ticket inspection machine load; When current flows from the bus power supply to the automatic ticket inspection machine load through the current detection resistor R1, a voltage difference exists across the current detection resistor R1. The voltage difference is respectively sent to the IN+ and IN- input terminals of the chip U1, and the chip U1 amplifies and outputs the voltage difference.

Images