Shield door safety circuit fault detection and control device

Abstract

The utility model discloses a fault detection and control device for a safety circuit of a shielding door, and relates to the field of circuits. A first voltage at two ends of a coil (a first input end and a second input end of a safety relay unit) of the safety relay unit in a safety loop, a second voltage between a power supply positive electrode and the first input end of the safety relay unit, and a third voltage between the second input end and a power supply negative electrode of the safety relay unit are detected; therefore, the state of the safety loop is detected. When the first voltage is lower than a preset first threshold value and the second voltage or the third voltage reaches a preset second threshold value, it is judged that the safety circuit breaks down, at the moment, the first relay unit and the second relay unit are closed, and the power source positive electrode of the safety relay unit is in short circuit with the first input end; and the second input end of the safety relay unit is short-circuited with the negative electrode of the power supply, so that the safety relay unit is normally driven, and the normal operation of the train is not influenced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a circuit technical field especially is related to a shielding door safety loop fault detection and control device. BACKGROUND

[0002] The shielding door of the subway platform is used for isolating the platform and the track and improving the equipment of riding safety. When the train enters the platform, the shielding door is controlled to open when the door opening command is sent, and the shielding door is controlled to close when the door closing command is sent. The train can only leave the platform after confirming that all the shielding doors are closed. Each shielding door is provided with a travel switch. When the shielding door is opened, the travel switch is opened, and when the shielding door is closed, the travel switch is closed. The travel switch contacts on the multiple shielding doors are connected in series to form a safety loop with a safety relay. When the safety loop is conducted, it is proved that all the shielding doors have been closed. At this time, the action signal of the closed shielding door is sent to the train control system to trigger the safety relay.

[0003] When the safety loop is normal, whether the shielding door is closed can be judged through the on-off of the safety loop, and the train operation is controlled. However, when the safety loop is faulty, the train may not be given an accurate control signal. For example, as the use time increases, the resistance in the safety loop will increase, so that even if all the travel switches are closed, the safety relay cannot be driven. Or when the shielding door is closed, the travel switch is not closed, so that the safety loop is open and the safety relay cannot be driven, thereby affecting the train operation. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the shielding door safety loop fault detection and control device is provided, and the technical problem that the safety loop fault affects the train operation is mainly solved.

[0005] The utility model provides a kind of shielding door safety loop fault detection and control device, and the device is used to detect and control the safety loop of multiple shielding doors on the same side of platform, the travel switch on the left door of each shielding door is connected in series to obtain first loop, the travel switch on the right door of each shielding door is connected in series to obtain second loop, and the safety loop includes the first loop, the second loop and safety relay unit, the first loop is connected between the power supply positive pole and first input end of the safety relay unit, and the second loop is connected between the second input end and power supply negative pole of the safety relay unit;The device includes:

[0006] Voltage detection module is used to detect the first voltage between the first input end and the second input end of the safety relay unit, the second voltage between the power supply positive pole and the first input end of the safety relay unit and the third voltage between the second input end and the power supply negative pole of the safety relay unit;

[0007] a first relay unit connected between a power supply positive pole of the safety relay unit and a first input terminal, contacts of the first relay unit being normally open;

[0008] a second relay unit connected between a second input terminal of the safety relay unit and a power supply negative pole, contacts of the second relay unit being normally open;

[0009] wherein, when the first voltage is lower than a preset first threshold value and the second voltage or the third voltage reaches a preset second threshold value, the first relay unit and the second relay unit are both closed.

[0010] In some embodiments, the device further comprises a control module, and the voltage detection module comprises a first voltage detection unit, the first voltage detection unit being an optical coupling relay.

[0011] an input terminal of the first voltage detection unit being connected with the first input terminal and the second input terminal of the safety relay unit, a first output terminal of the first voltage detection unit being connected with a voltage source, and a second output terminal of the first voltage detection unit being connected with the control module; wherein the first voltage detection unit is configured to detect the first voltage, and when the first voltage reaches the first threshold value, the first output terminal and the second output terminal of the first voltage detection unit are turned on.

[0012] In some embodiments, the device further comprises a third relay unit, a fourth relay unit and a fifth relay unit, the third relay unit, the fourth relay unit and the fifth relay unit each comprising two groups of relays, the two groups of relays of the third relay unit each being a single-pole double-throw relay; the voltage detection module further comprises a second voltage detection unit and a third voltage detection unit, the second voltage detection unit and the third voltage detection unit each being an optical coupling relay.

[0013] a first input terminal of the second voltage detection unit being connected with the power supply positive pole of the safety relay unit, a second input terminal of the second voltage detection unit being connected with a common terminal of a first group of relays of the third relay unit, a first output terminal of the second voltage detection unit being connected with the voltage source, and a second output terminal of the second voltage detection unit being connected with the control module;

[0014] a first input terminal of the third voltage detection unit being connected with a common terminal of a second group of relays of the third relay unit, a second input terminal of the third voltage detection unit being connected with the power supply negative pole of the safety relay unit, a first output terminal of the third voltage detection unit being connected with the voltage source, and a second output terminal of the third voltage detection unit being connected with the control module;

[0015] In the third relay unit, the normally closed end of the first group of relays is connected to the first end of the first group of relays in the fourth relay unit, and the normally open end of the first group of relays is connected to the first end of the second group of relays in the fourth relay unit.

[0016] In the third relay unit, the normally closed end of the second group of relays is connected to the first end of the second group of relays in the fourth relay unit, and the normally open end of the second group of relays is connected to the first end of the first group of relays in the fourth relay unit.

[0017] In the fourth relay unit, the second end of the first group of relays is connected to the first end of the first group of relays in the fifth relay unit, and the second end of the second group of relays is connected to the first end of the second group of relays in the fifth relay unit.

[0018] In the fifth relay unit, the second end of the first group of relays is connected to the first input end of the safety relay unit, and the second end of the second group of relays is connected to the second input end of the safety relay unit.

[0019] The control end of the third relay unit, the control end of the fourth relay unit, and the control end of the fifth relay unit are all connected to the control module, the contact of the fourth relay unit is normally open, and the contact of the fifth relay unit is normally closed.

[0020] In some embodiments, one end of the first loop is connected to the positive electrode of the power supply of the safety relay unit, the other end is connected to the first input end of the safety relay unit through the first group of relays in the fifth relay unit, and a plurality of travel switches in the first loop are connected in series between the positive electrode of the power supply of the safety relay and the first end of the first group of relays in the fifth relay unit.

[0021] One end of the second loop is connected to the second input end of the safety relay unit through the second group of relays in the fifth relay unit, and the other end is connected to the negative electrode of the power supply of the safety relay unit, and a plurality of travel switches in the second loop are connected in series between the negative electrode of the power supply of the safety relay and the first end of the second group of relays in the fifth relay unit.

[0022] In some embodiments, the device further comprises: a first current-limiting resistor and a second current-limiting resistor.

[0023] One end of the first current-limiting resistor is connected to the normally open end of the second group of relays in the third relay unit, and the other end of the first current-limiting resistor is connected to the first end of the first group of relays in the fourth relay unit.

[0024] One end of the second current-limiting resistor is connected with the normally open end of the first group of relays of the third relay unit, and the other end of the second current-limiting resistor is connected with the first end of the second group of relays of the fourth relay unit.

[0025] In some embodiments, when the first voltage is lower than the first threshold value, the fourth relay unit is closed, and after the fourth relay unit is closed, the second voltage detection unit detects the second voltage, and the third voltage detection unit detects the third voltage.

[0026] In some embodiments, when the second voltage or the third voltage reaches the second threshold value, the fifth relay unit is opened, and the third relay unit is switched to connect the second voltage detection unit in series with the second loop and the third voltage detection unit in series with the first loop.

[0027] In some embodiments, when the second voltage or the third voltage reaches the second threshold value, the fifth relay unit is opened, and the third relay unit is switched to connect the second voltage detection unit in series with the second loop and the third voltage detection unit in series with the first loop.

[0028] In some embodiments, when the second voltage or the third voltage reaches the second threshold value, the fifth relay unit is opened, and the third relay unit is switched to connect the second voltage detection unit in series with the second loop and the third voltage detection unit in series with the first loop.

[0029] When the second voltage detection module is turned on and / or the third voltage detection module is turned on, the first relay unit and the second relay unit are both closed.

[0030] In some embodiments, the device further comprises a changeover switch, the changeover switch being provided with a first changeover position and a second changeover position, and the changeover switch being connected with the control module.

[0031] If the changeover switch is switched to the first changeover position, when the third voltage detection unit is turned on, the second relay unit is closed; and when the second voltage detection unit is turned on, the first relay unit is closed.

[0032] If the changeover switch is switched to the second changeover position, when the second voltage detection unit is turned on or the third voltage detection unit is turned on, the first relay unit is closed and the second relay unit is closed.

[0033] In some embodiments, the device further comprises a reset switch connected to the control module, wherein the reset switch is configured to send a reset signal to reset each relay unit to a default state in response to a reset operation.

[0034] In some embodiments, each shielding door is provided with a door controller and a door status indicator, the door status indicator is connected to the door controller, the door controller is configured to control the shielding door to perform an opening action, a closing action, maintain an open state, or maintain a closed state; the device further comprises a fourth voltage detection unit and a fifth voltage detection unit;

[0035] For each shielding door, a fourth voltage detection unit is connected to the travel switch on the left door, and a fifth voltage detection unit is connected to the travel switch on the right door, the output of the fourth voltage detection unit and the output of the fifth voltage detection unit are both connected to the door controller;

[0036] The fourth voltage detection unit is configured to detect whether the travel switch on the left door of the shielding door is open or closed;

[0037] The fifth voltage detection unit is configured to detect whether the travel switch on the right door of the shielding door is open or closed;

[0038] The door controller is configured to, when the shielding door is in a closed state, if it is detected that the travel switch on the left door and / or the travel switch on the right door is open, control the door status indicator to indicate a shielding door closing failure in a preset display mode.

[0039] The shielding door safety loop fault detection and control device provided by the application detects the state of the safety loop by detecting a first voltage at both ends of an equivalent coil of a safety relay unit (a first input end and a second input end of the safety relay unit), a second voltage between a positive electrode of a power supply of the safety relay unit and the first input end, and a third voltage between the second input end of the safety relay unit and a negative electrode of the power supply. For each shielding door, a travel switch on a left door is connected to a first loop, and a travel switch on a right door is connected to a second loop. The left door and the right door are controlled by the same transmission mechanism, and the left door and the right door perform the same door opening and closing action. Under normal circumstances, when the shielding door is opened, the left door and the right door are both opened, the travel switches on the left door and the right door are both disconnected, and the first loop and the second loop are both disconnected. When the shielding door is closed, the left door and the right door are both closed, the travel switches on the left door and the right door are both connected, and the first loop and the second loop are both connected. When the first voltage is detected to be lower than a preset first threshold value, and the second voltage or the third voltage reaches a preset second threshold value, it is indicated that one of the first safety loop and the second safety loop is connected and the voltage drop is normal (does not exceed the second threshold value), and the other loop causes the voltage drop to be too large (exceeds the second threshold value) due to increased resistance or disconnection. At this time, the shielding door should be in the closed state. However, due to the voltage drop of one loop, the voltage at both ends of the equivalent coil of the safety relay unit is reduced to be insufficient to drive the safety relay unit to act, so although the shielding door is closed, the safety relay unit cannot send an action signal to the train control system, and the train cannot be controlled to start, and thus it is determined that a fault occurs in the safety loop. At this time, the first relay unit and the second relay unit are closed to short-circuit the positive electrode of the power supply of the safety relay unit and the first input end, and to short-circuit the second input end of the safety relay unit and the negative electrode of the power supply, so that the safety relay unit is normally driven to send an action signal, and the train control system is informed that all the shielding doors on the same side of the platform are closed, and then the train control system can control the train to start, thereby eliminating the influence of the safety loop fault on train operation.

[0040] The above description is only a summary of the technical solutions of the application, in order to more clearly understand the technical means of the application, the application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following specific embodiments of the application are described. BRIEF DESCRIPTION OF DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and the descriptions thereof are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0042] Figure 1The circuit structure schematic diagram of the shielding door safety loop fault detection and control device is shown.

[0043] Figure 2 The circuit structure schematic diagram of the shielding door safety loop fault detection and control device is shown.

[0044] Figure 3 The circuit structure schematic diagram of the shielding door safety loop fault detection and control device is shown.

[0045] The circuit structure schematic diagram of the shielding door safety loop fault detection and control device is shown.

[0046] 1, the positive electrode of the power supply of the safety relay unit; 2, the first input end of the safety relay unit; 3, the second input end of the safety relay unit; 4, the negative electrode of the power supply of the safety relay unit; A1, the first voltage detection unit; A2, the second voltage detection unit; A3, the third voltage detection unit; A4, the fourth voltage detection unit; A5, the fifth voltage detection unit; P1, the second output end of the first voltage detection unit; P2, the second output end of the second voltage detection unit; P3, the second output end of the third voltage detection unit; Relay1, the first relay unit; Relay2, the second relay unit; Relay3, the third relay unit; Relay4, the fourth relay unit; Relay5, the fifth relay unit; ASD, the shielding door; DCU, the door controller; R1, the first current limiting resistor; R2, the second current limiting resistor. DETAILED DESCRIPTION

[0047] The utility model will be described in detail below with reference to the drawings and in combination with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0048] It should be understood that the terms "first", "second", and various numerical designations are only used for differentiation for convenience of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. When an element is "connected" to another element, the element can be directly connected to the other element, or there can be an intermediate element. "And / or" is used to describe the association between objects, which means that there can be three relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone, wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects.

[0049] In one embodiment, as shown in Figure 1 , a shielding door safety loop fault detection and control device is provided, which is used for Figure 2The safety circuit shown for the same side of the platform multiple shield doors is detected and controlled, the travel switches on the left door of each of the shield doors are connected in series to obtain a first circuit, the travel switches on the right door of each of the shield doors are connected in series to obtain a second circuit, the safety circuit includes the first circuit, the second circuit and a safety relay unit, the first circuit is connected between the power supply positive pole 1 and the first input end 2 of the safety relay unit, and the second circuit is connected between the second input end 3 of the safety relay unit and the power supply negative pole 4; the device includes: a voltage detection module, a first relay unit Relay1 and a second relay unit Relay2. Wherein, the voltage detection module is used for detecting the first voltage between the first input end 2 and the second input end 3 of the safety relay unit, the second voltage between the power supply positive pole 1 and the first input end 2 of the safety relay unit, and the third voltage between the second input end 3 and the power supply negative pole 4 of the safety relay unit. The first relay unit Relay1 is connected between the power supply positive pole 1 and the first input end 2 of the safety relay unit, and the contact of the first relay unit Relay1 is normally open. The second relay unit Relay2 is connected between the second input end 3 and the power supply negative pole 4 of the safety relay unit, and the contact of the second relay unit Relay2 is normally open. When the first voltage is lower than a preset first threshold value, and the second voltage or the third voltage reaches a preset second threshold value, the first relay unit Relay1 and the second relay unit Relay2 are closed.

[0050] The shield door (also known as platform door) is arranged on the subway platform and is used to isolate the platform from the train track to ensure the safety of passengers. After the train enters the platform, the control system sends an opening command to control the shield door to open, and after the passengers get on the train, a closing command is sent to control the shield door to close, and the train can only leave the platform after confirming that the shield door is completely closed. Usually, a shield door safety circuit is used to detect whether the shield door is completely closed after the closing command is sent. Figure 2 As shown, a shield door safety circuit schematic diagram is provided. Usually, a shield door includes a left door and a right door, and each of the left door and the right door has a group of travel switches. Under normal circumstances, the travel switches on the left door and the right door are both disconnected when the shield door is opened, and the travel switches on the left door and the right door are both closed when the shield door is closed. Figure 2 ASD represents a shield door, Figure 2The left door and the right door of each of the shield doors shown in the figure has two travel switches. In the safety circuit provided by the embodiment, the travel switches on each shield door on the same side of the platform are connected in series as left door and right door to obtain two circuits, that is, the travel switches on the left door of all the shield doors on the same side of the platform are connected in series to obtain a first circuit, and the travel switches on the right door of all the shield doors on the same side of the platform are connected in series to obtain a second circuit. In an implementation, assuming that there are 30 shield doors on one side of the platform, and each shield door has two travel switches on the left door and the right door, then 60 travel switches on the left door are connected in series in the first circuit, and 60 travel switches on the right door are connected in series in the second circuit. The first circuit and the second circuit are connected with a safety relay unit, thereby obtaining a safety circuit for the plurality of shield doors on the same side of the platform.

[0051] The safety relay unit includes four input terminals, that is, a power supply positive pole 1, a first input terminal 2, a second input terminal 3, and a power supply negative pole 4. The power supply positive pole 1 and the power supply negative pole 4 are used to provide an input voltage, and the first input terminal 2 and the second input terminal 3 are equivalent to two ends of an internal equivalent coil of the safety relay unit. In the safety circuit, two ends of the first circuit are connected with the power supply positive pole 1 and the first input terminal 2 of the safety relay unit respectively, and two ends of the second circuit are connected with the second input terminal 3 and the power supply negative pole 4 of the safety relay unit respectively.

[0052] Ideally, after a control command of closing the shield doors is sent, if all the shield doors are closed, all the travel switches in the first circuit and the second circuit are closed, that is, the first circuit and the second circuit are both conducted, at this time, the first input terminal 2 of the safety relay unit is at the same potential as the power supply positive pole 1, the second input terminal 3 is at the same potential as the power supply negative pole 4, and the voltage between the first input terminal 2 and the second input terminal 3 is approximately equal to the input voltage of the safety relay unit. The input voltage of the safety relay unit is greater than the driving voltage, thereby driving the safety relay unit to act, so that the safety relay unit sends an action signal to the train control system that all the shield doors have been closed, and then the train control system can control the train to leave the platform. If not all the shield doors are closed after the control command of closing the shield doors is sent, that is, there is a shield door that is not closed, the voltage between the first input terminal 2 and the second input terminal 3 of the safety relay unit cannot drive the safety relay unit to act, at this time, the train cannot be controlled to leave the platform. Therefore, through the safety circuit, it can be ensured that the train is controlled to run after all the shield doors are closed, thereby ensuring the safety of passengers.

[0053] However, in practical application, with the increase of the service life, the contact of the shield door travel switch will form an oxide film under the action of electric arc, thus increasing the resistance in the safety circuit. In addition, the oxide film on the contact of the travel switch is not uniform, and the position of the contact when the travel switch is closed each time is not strictly fixed, thus leading to the inconsistency of the resistance in the circuit each time the travel switch is closed. Since the safety relay unit has a driving voltage requirement, that is, the voltage between the first input end 2 and the second input end 3 of the safety relay unit can only drive the safety relay unit to act when the voltage reaches the driving voltage. The increase of the resistance in the safety circuit will cause a voltage drop between the positive electrode 1 of the power supply and the first input end 2 of the safety relay unit and a voltage drop between the second input end 3 and the negative electrode 4 of the power supply, thus reducing the voltage between the first input end 2 and the second input end 3 of the safety relay unit. When the resistance in the safety circuit increases to a value that makes the voltage between the first input end 2 and the second input end 3 of the safety relay unit lower than the driving voltage, even if the travel switches in the first circuit and the second circuit are all closed, the safety relay unit cannot be driven to act. In addition, there may also be a situation that all the shield doors are closed, but the travel switches are faulty and open, in which case the safety relay unit cannot be driven to act. That is, in practical application, there may be a situation that even if all the shield doors are closed, the safety relay unit cannot be driven to act, thus affecting the normal operation of the train.

[0054] Based on this, the embodiment detects the voltage across the equivalent coil of the safety relay unit and the voltage drops of the first circuit and the second circuit to detect the fault of the safety circuit, and shorts the equivalent coil of the safety relay unit to the positive electrode 1 of the power supply and the negative electrode 4 of the power supply respectively when a fault is detected, to drive the safety relay unit to act normally and eliminate the influence of the fault of the safety circuit on the normal operation of the train.

[0055] Specifically, the voltage detection module detects the first voltage between the first input end 2 and the second input end 3 of the safety relay unit, the second voltage between the positive electrode 1 of the power supply and the first input end 2 of the safety relay unit, and the third voltage between the second input end 3 of the safety relay unit and the negative electrode 4 of the power supply. Since the greater the resistance in the first circuit or the second circuit, the greater the second voltage or the third voltage and the smaller the first voltage, the first threshold value is set for the first voltage, and the second threshold value is set for the second voltage and the third voltage. When the first voltage is lower than the first threshold value and the second voltage or the third voltage reaches the second threshold value, it indicates that the safety circuit has a fault. The first threshold value and the second threshold value can be determined according to the input voltage and the driving voltage of the safety relay unit.

[0056] In one specific embodiment, assuming that the input voltage of the safety relay unit (i.e. the voltage between the power supply positive pole 1 and the power supply 4) is 60V, the drive voltage of the safety relay unit is 47.5V, and the safety relay unit cannot be driven to act below 47.5V. Then the voltage drop of the first loop and the second loop together cannot exceed 60V-47.5V=12.5V, and the voltage drop of each loop cannot exceed 12.5V÷2=6.25V. In order to leave a certain redundancy space for fault detection, the voltage drop of one loop can be set to reach 6.25V, and then the safety loop is controlled. Therefore, the first threshold value can be set to be about 60V-6.25V=53.75V, for example, 53±1V, and the second threshold value can be set to be 6.25±1V. It should be noted that the specific values of the first threshold value and the second threshold value in the embodiment are only examples, and can be determined according to actual conditions.

[0057] Generally, the resistance values in the first loop and the second loop are close, so when the first voltage is lower than the first threshold value, the second voltage and the third voltage can both not exceed the second threshold value (i.e. the voltage drops of the first loop and the second loop both do not exceed the second threshold value), and at this time, the safety loop fault is not determined. When the first voltage is lower than the first threshold value, and the second voltage or the third voltage exceeds the second threshold value, the safety loop fault is determined, and at this time, the safety relay unit is driven to act.

[0058] Specifically, a first relay unit Relay1 can be connected between the power supply positive pole 1 and the first input end 2 of the safety relay unit, and a second relay unit Relay2 can be connected between the second input end 3 and the power supply negative pole 4 of the safety relay unit, and the contacts of the first relay unit Relay1 and the second relay unit Relay2 are normally open. When the first voltage is lower than the first threshold value, and the second voltage or the third voltage reaches the second threshold value, the first relay unit Relay1 and the second relay unit Relay2 are closed, the power supply positive pole 1 of the safety relay unit is short-circuited with the first input end 2, and the second input end 3 of the safety relay unit is short-circuited with the power supply negative pole 4, so as to drive the safety relay unit to normally act when the shield door is closed, and eliminate the influence of the fault on the train operation.

[0059] In the embodiment, the first relay unit Relay1 and the second relay unit Relay2 can be controlled to drive by a control module (or a controller, a control unit, etc.), which can be connected with the control end of the first relay unit Relay1 and the control end of the second relay unit Relay2. The voltage detection module can be connected with the control module to send the voltage detection result to the control module. When the first voltage is lower than the first threshold value and the second voltage or the third voltage reaches the second threshold value, the control module drives the first relay unit Relay1 and the second relay unit Relay2 to be closed. The functions of the control module, such as the comparison of the voltage and the threshold value, the output of the driving signal, etc. can be realized by a hardware circuit or by an existing program module in the control module.

[0060] The safety circuit fault detection and control device provided by the application detects the state of the safety circuit by detecting the first voltage between the two ends of the coil of the safety relay unit (the first input end 2 and the second input end 3), the second voltage between the positive electrode 1 of the power supply of the safety relay unit and the first input end 2, and the third voltage between the second input end 3 of the safety relay unit and the negative electrode 4. For each screen door, the travel switch on the left door is connected to the first circuit, and the travel switch on the right door is connected to the second circuit. The left door and the right door are controlled by the same transmission mechanism when the screen door is closed or opened, that is, the left door and the right door perform the same door opening and closing action. Under normal circumstances, when the screen door is opened, the left door and the right door are both opened, the travel switches on the left door and the right door are both disconnected, and the first circuit and the second circuit are both disconnected. When the screen door is closed, the left door and the right door are both closed, the travel switches on the left door and the right door are both connected, and the first circuit and the second circuit are both connected. When it is detected that the first voltage is lower than the preset first threshold value and the second voltage or the third voltage reaches the preset second threshold value, it indicates that one of the first safety circuit and the second safety circuit is connected and the voltage drop is normal (does not exceed the second threshold value), and the other circuit causes the voltage drop to be too large (exceeds the second threshold value) due to the increase of the resistance or the disconnection. At this time, the screen door should be in the closed state. However, due to the increase of the voltage drop of one circuit, the voltage between the two ends of the equivalent coil of the safety relay unit is reduced to be insufficient to drive the safety relay unit to act, so although the screen door is closed, the safety relay unit cannot send an action signal to the train control system, and the train cannot be controlled to start, so it is determined that the safety circuit has failed. At this time, by closing the first relay unit Relay1 and the second relay unit Relay2, the positive electrode 1 of the power supply of the safety relay unit and the first input end 2 are short-circuited, and the second input end 3 of the safety relay unit and the negative electrode are short-circuited, so that the safety relay unit is normally driven to send an action signal, informing the train control system that all the screen doors on the same side of the platform have been closed, and then the train control system can control the train to start, thereby eliminating the influence of the safety circuit failure on the train operation.

[0061] In one embodiment, as shown in Figure 1 The shielding door safety circuit fault detection and control device provided by the embodiments of the present application further includes a control module. The voltage detection module includes a first voltage detection unit A1, a second voltage detection unit A2, and a third voltage detection unit A3, all of which are optocoupler relays. Two input ends of the first voltage detection unit A1 are connected with a first input end 2 and a third input end 3 of the safety relay unit respectively, a first output end of the first voltage detection unit A1 is connected with a voltage source (for example, the first output end is connected with a 24V direct current voltage), and a second output end P1 is connected with the control module. The first voltage detection unit A1 is used for detecting a first voltage between the first input end 2 and the third input end 3 of the safety relay unit, and when the first voltage reaches a first threshold value, the first output end and the second output end P1 of the first voltage detection unit A1 are turned on. Figure 1

[0062] As shown in Figure 1 The shielding door safety circuit fault detection and control device provided by the embodiments of the present application further includes a third relay unit Relay3, a fourth relay unit Relay4, and a fifth relay unit Relay5. The third relay unit Relay3, the fourth relay unit Relay4, and the fifth relay unit Relay5 each include two groups of relays, and the two groups of relays of the third relay unit Relay3 are both single-pole double-throw relays.

[0063] A first input end of the second voltage detection unit A2 is connected with a positive electrode 1 of the power supply of the safety relay unit, a second input end of the second voltage detection unit A2 is connected with a common end of a first group of relays of the third relay unit Relay3, a first output end of the second voltage detection unit A2 is connected with a voltage source, and a second output end P3 of the second voltage detection unit A2 is connected with the control module. A normally closed end of the first group of relays of the third relay unit Relay3 is connected with a first end of a first group of relays of the fourth relay unit Relay4, and a normally open end of the first group of relays of the third relay unit Relay3 is connected with a first end of a second group of relays of the fourth relay unit Relay4. A second end of the first group of relays of the fourth relay unit Relay4 is connected with a first end of a first group of relays of the fifth relay unit Relay5, and a second end of the first group of relays of the fifth relay unit Relay5 is connected with the first input end 2 of the safety relay unit.

[0064] ​The first input end of the third voltage detection unit A3 is connected with the common end of the second group of relays of the third relay unit Relay3, the second input end of the third voltage detection unit A3 is connected with the power negative pole 4 of the safety relay unit, the first output end of the third voltage detection unit A3 is connected with the voltage source, and the second output end P3 of the third voltage detection unit A3 is connected with the control module. The normally closed end of the second group of relays of the third relay unit Relay3 is connected with the first end of the second group of relays of the fourth relay unit Relay4, and the normally open end of the second group of relays of the third relay unit Relay3 is connected with the first end of the first group of relays of the fourth relay unit Relay4. The second end of the second group of relays of the fourth relay unit Relay4 is connected with the first end of the second group of relays of the fifth relay unit Relay5, and the second end of the second group of relays of the fifth relay unit Relay5 is connected with the second input end 3 of the safety relay unit.

[0065] The control end of the third relay unit Relay3, the control end of the fourth relay unit Relay4, and the control end of the fifth relay unit Relay5 are all connected with the control module, wherein the contact of the fourth relay unit Relay4 is normally open, and the contact of the fifth relay unit Relay5 is normally closed.

[0066] One end of the first loop is connected with the power positive pole 1 of the safety relay unit, and the other end is connected with the first input end 2 of the safety relay unit through the first group of relays of the fifth relay unit Relay5, and a plurality of travel switches in the first loop are connected in series between the power positive pole 1 of the safety relay unit and the first end of the first group of relays of the fifth relay unit Relay5. One end of the second loop is connected with the second input end 3 of the safety relay unit through the second group of relays of the fifth relay unit Relay5, and the other end is connected with the power negative pole 4 of the safety relay unit, and a plurality of travel switches in the second loop are connected in series between the power negative pole 4 of the safety relay unit and the first end of the second group of relays of the fifth relay unit Relay5.

[0067] When the first voltage is lower than the first threshold value, the fourth relay unit Relay4 is closed, and after the fourth relay unit Relay4 is closed, the second voltage detection unit A2 detects the second voltage, and the third voltage detection unit A3 detects the third voltage. Wherein when the second voltage reaches the second threshold value, the first output end and the second output end P2 of the second voltage detection unit are turned on, and when the third voltage reaches the second threshold value, the first output end and the second output end P3 of the third voltage detection unit are turned on.

[0068] When the second voltage or the third voltage reaches the second threshold, the fifth relay unit Relay5 is disconnected, and the third relay unit Relay3 is switched, so that the second voltage detection unit A2 is connected in series with the second circuit, and the third voltage detection unit A3 is connected in series with the first circuit. When all the limit switches in the first circuit are closed and the resistance of the limit switches in the first circuit is less than the sensitivity threshold, the first output terminal and the second output terminal P3 of the third voltage detection unit A3 are turned on. When all the limit switches in the second circuit are closed and the resistance of the limit switches in the second circuit is less than the sensitivity threshold, the first output terminal and the second output terminal P2 of the second voltage detection unit A2 are turned on. When the second voltage detection module is turned on and / or the third voltage detection module is turned on, both the first relay unit Relay1 and the second relay unit Relay2 are closed.

[0069] In the above embodiment, when the optocoupler relay is conducting, the second output terminal is high, that is, the output is 1, and when it is not conducting, the second output terminal is low, that is, the output is 0. The third relay unit Relay3, the fourth relay unit Relay4, and the fifth relay unit Relay5 can be controlled and driven by the control module.

[0070] In the above embodiment, the on-voltage of the first voltage detection unit A1 is equivalent to the voltage corresponding to the first threshold, the on-voltage of the second voltage detection unit A2 is equivalent to the voltage corresponding to the second threshold, and the on-voltage of the third voltage detection unit A3 is equivalent to the voltage corresponding to the second threshold. For different voltage detection units, the model of the optocoupler relay can be selected based on the on-voltage, or the corresponding on-voltage can be set by connecting a resistor in series at the input end of the optocoupler relay.

[0071] Specifically, the control module is configured to control the fourth relay unit Relay4 to close when the first voltage is lower than the first threshold, that is, when the first voltage detection unit A1 outputs a low level, so that the second voltage detection unit A2 detects the second voltage between the positive power supply terminal 1 and the first input terminal 2 of the safety relay unit, and the third voltage detection unit A3 detects the third voltage between the second input terminal 3 and the negative power supply terminal 4 of the safety relay unit. When the second voltage is lower than the second threshold, the second voltage detection unit A2 outputs a low level; when the second voltage reaches the second threshold, the second voltage detection unit A2 outputs a high level; when the third voltage is lower than the second threshold, the third voltage detection unit A3 outputs a low level; and when the third voltage reaches the second threshold, the third voltage detection unit A3 outputs a high level. It should be noted that in this embodiment, when the first voltage detection unit A1, the second voltage detection unit A2, and the third voltage detection unit A output a high level or a low level, this means that the second output terminal exhibits a high level or a low level.

[0072] The control module is further configured to control the fifth relay unit Relay5 to be open and control the third relay to switch when the second voltage detection unit A2 or the third voltage detection unit A3 outputs a high level, and control the second voltage detection unit A2 to be in series with the second loop and the third voltage detection unit A3 to be in series with the first loop. When all the travel switches in the first loop are closed and the resistance of the travel switches in the first loop is less than the sensitivity threshold, the third voltage detection unit A3 is turned on and outputs a high level; when all the travel switches in the second loop are closed and the resistance of the travel switches in the second loop is less than the sensitivity threshold, the second voltage detection unit A2 is turned on and outputs a high level. The control module is further configured to control the first relay unit Relay1 and the second relay unit Relay2 to be closed when the third voltage detection unit A3 and / or the second voltage detection unit A2 outputs a high level.

[0073] In the above embodiment, when the first voltage is lower than the first threshold value, it indicates that the safety circuit may have a fault, at this time, the second voltage and the third voltage need to be further judged. Specifically, the contact of the fourth relay unit Relay4 is always open, and the second voltage detection unit A2 and the third voltage detection unit A3 do not measure the second voltage and the third voltage when the fourth relay unit Relay4 is open. When the first voltage is lower than the first threshold value, the first voltage detection unit A1 is not turned on and outputs a low level, and the control module detects that the first voltage detection unit A1 outputs a low level, and drives the fourth relay unit Relay4 to be closed. After the fourth relay unit Relay4 is closed, the second voltage detection unit A2 detects the second voltage and the third voltage detection unit A3 detects the third voltage. If the second voltage and the third voltage are both lower than the second threshold value, the second voltage detection unit A2 and the third voltage detection unit A3 are not turned on and both output a low level, i.e. 00, at this time, it is determined that the safety circuit has no fault. When one of the second voltage and the third voltage exceeds the second threshold value, one of the second voltage detection unit A2 and the third voltage detection unit A3 is turned on, i.e. one outputs a high level and the other outputs a low level, and the control module detects that the output signals of the second voltage detection unit A2 and the third voltage detection unit A3 are 10 or 01, and then determines that the safety circuit has a fault.

[0074] After determining that the safety circuit has a fault, the control module drives the fifth relay unit Relay5 to be disconnected, that is, the first input end 2 of the safety relay unit is disconnected from the first circuit, and the second input end 3 of the safety relay unit is disconnected from the second circuit. The control module simultaneously controls the single-pole double-throw switch of the third relay unit Relay3 to switch, so that the second input end of the second voltage detection unit A2 is connected to the second group of relays of the fourth relay unit Relay4, and the first input end of the third voltage detection unit A3 is connected to the first group of relays of the fourth relay unit Relay4. Thus, the positive electrode 1 of the power supply of the safety relay unit, the second voltage detection unit A2, the travel switch connected in series in the second circuit, and the negative electrode of the power supply of the safety relay unit form a circuit. The positive electrode 1 of the power supply of the safety relay, the travel switch connected in series in the first circuit, the third voltage detection unit A3, and the negative electrode 4 of the power supply of the safety relay form a circuit. That is, the second voltage detection unit A2 is connected in series with the travel switch in the second circuit, and the third voltage detection unit A3 is connected in series with the travel switch in the first circuit. When all the travel switches in the first circuit are closed and the current is greater than the driving current of the third voltage detection unit A3, the third voltage detection unit A3 is turned on and outputs a high level. When all the travel switches in the second circuit are closed and the current is greater than the driving current of the second voltage detection unit A2, the second voltage detection unit A2 is turned on and outputs a high level. The current in the circuit is related to the resistance of the travel switch, and the current is greater than the driving current of the second voltage detection unit A2 or the third voltage detection unit A3, that is, the resistance value of the travel switch in the circuit is less than the sensitivity threshold of the circuit. For example, assuming that the driving current of the second voltage detection unit A2 and the third voltage detection unit A3 is 0.9 mA, when the resistance value in the circuit is greater than 30 kΩ, the circuit current is less than 0.9 mA, and the sensitivity threshold is 30 kΩ.

[0075] When the control module detects that the second voltage detection unit A2 and / or the third voltage detection unit A3 output a high level, the control module controls the first relay unit Relay1 and the second relay unit Relay2 to be turned on, so as to drive the safety relay unit to act. When the shielding door is opened, the travel switches in the first circuit and the second circuit are disconnected, the second voltage detection unit A2 and the third voltage detection unit A3 are not turned on, the control module does not control the first relay unit Relay1 and the second relay unit Relay2 to be closed, and the safety relay unit is not driven. It can be seen that the shielding door safety circuit fault detection and control device provided in the embodiment of the application can detect the safety circuit fault when the shielding door is closed, can eliminate the influence of the fault through control of the safety circuit, and will not affect the normal use of the safety circuit when the shielding door is opened.

[0076] In one embodiment, the shielding door safety circuit fault detection and control device provided by the embodiments of the present application further comprises a changeover switch, the changeover switch is provided with a first changeover position and a second changeover position, and the changeover switch is connected with the control module. If the changeover switch is changed to the first changeover position, the second relay unit Relay2 is closed when the third voltage detection unit A3 is turned on, and the first relay unit Relay1 is closed when the second voltage detection unit A2 is turned on. If the changeover switch is changed to the second changeover position, the first relay unit Relay1 and the second relay unit Relay2 are closed when the second voltage unit A2 or the third voltage detection unit A3 is turned on.

[0077] In the above embodiment, the first relay unit Relay1 and the second relay unit Relay2 can be controlled and driven by the control module, and the control module can control the first relay unit Relay1 and the second relay unit Relay2 to be closed in two ways. Specifically, a changeover switch can be provided, the changeover switch is connected with the control module, the changeover switch is provided with two changeover positions, and different changeover positions correspond to different control modes. One way is to place the changeover switch in the first changeover position, that is, the "and" position, and control the first relay unit Relay1 and the second relay unit Relay2 to be closed by the second voltage detection unit A2 and the third voltage detection unit A3 respectively. This way requires that the travel switches in the first circuit and the second circuit are both turned on, and the resistance is lower than the sensitivity threshold. Another way is to place the changeover switch in the second changeover position, that is, the "or" position, and control the first relay unit Relay1 and the second relay unit Relay2 to be closed by one of the second voltage detection unit A2 and the third voltage detection unit A3. This way allows one of the first circuit and the second circuit to be open.

[0078] In the above embodiment, after the second voltage detection module A2 and the third voltage detection module A3 are connected in series in the circuit, the sensitivity threshold in the circuit is higher than that of the original shielding door safety circuit. In one specific example, the original resistance sensitivity of the safety relay unit is about 900Ω, that is, when the resistance in the safety circuit exceeds 900Ω, the safety relay unit cannot be driven. After the shielding door safety circuit fault detection and control device provided by the embodiments of the present application is applied, the maximum resistance in the circuit can be allowed to be about 40kΩ, that is, the travel switch in the safety circuit can be allowed to have a larger resistance.

[0079] In the above embodiment, the safety circuit fault can also be manifested as the shield door being closed but the travel switch not being closed, i.e. the first circuit or the second circuit being broken. Taking the first circuit being broken and the second circuit being conducted as an example, the two input terminals of the voltage detection unit A2 are connected between the power supply positive pole 1 and the first input terminal 2 of the safety relay unit to measure the second voltage. When the first circuit is broken, there should originally be no voltage between the power supply positive pole 1 and the first input terminal 2 of the safety relay unit, but since the voltage detection unit A2 is connected between the power supply positive pole 1 and the first input terminal 2, a path is formed between the power supply positive pole 1 and the first input terminal 2 through the voltage detection unit A2 when the first circuit is broken. The voltage detection unit A2 is conducted, the second voltage detection unit A2 outputs a high level, and at this time the voltage drop (i.e. the second voltage) between the power supply positive pole 1 and the first input terminal 2 caused by the internal resistance of the voltage detection unit A2 is greater than the second threshold value. The second circuit is a path, and the third voltage detection unit A3 outputs a low level. Therefore, the control of the safety circuit is triggered in this case, and the safety relay unit is driven to act. That is, by applying the shield door safety circuit fault detection and control device provided in the present application, not only can the safety circuit fault caused by the increase of the resistance in the safety circuit be eliminated, but also the safety circuit fault caused by the broken travel switch can be eliminated, without affecting the normal operation of the train.

[0080] In one embodiment, the shield door safety circuit fault detection and control device provided in the present embodiment further comprises a first current-limiting resistor R1 and a second current-limiting resistor R2. One end of the first current-limiting resistor R1 is connected to the normally open end of the second group of relays of the third relay unit Relay3, and the other end of the first current-limiting resistor R1 is connected to the first end of the first group of relays of the fourth relay unit Relay4. One end of the second current-limiting resistor R2 is connected to the normally open end of the first group of relays of the third relay unit Relay3, and the other end of the second current-limiting resistor R2 is connected to the first end of the second group of relays of the fourth relay unit Relay4.

[0081] In the above embodiment, the first current-limiting resistor R1 and the second current-limiting resistor R2 are used to prevent the current in the circuit from being too large to burn out the power supply of the safety relay unit after the second voltage detection unit A2 and the third voltage detection unit A3 are connected in series in the circuit. At the same time, the resistance sensitivity threshold of the travel switch in the circuit is also affected by the resistance value of the current-limiting resistor. For example, assuming that the maximum resistance allowed in the circuit is 40k, if the resistance value of the current-limiting resistor is 10k, the resistance sensitivity threshold of the travel switch is 40k-10k=30k, i.e. the travel switch can have a resistance of 30k after being closed. Based on this, the resistance value of the first current-limiting resistor R1 and the second current-limiting resistor R2 can be determined according to the requirements of the safety relay unit for the current and the actual situation, to ensure that the safety relay unit is protected.

[0082] In one embodiment, each group of relays in the relay unit in the embodiment of the present application can be obtained by connecting two relays in parallel, thereby improving the reliability of the relay unit action.

[0083] In one embodiment, the shield door safety circuit fault detection and control device provided in the embodiment of the present application further comprises a reset switch connected with the control module. The reset switch is used to send a reset signal in response to a reset operation, so as to restore each relay unit to a default state.

[0084] In the above embodiment, the control module is further used to control each relay unit to restore to the default state when the reset switch sends the reset signal.

[0085] In the above embodiment, the reset switch can be started at a predetermined time interval, for example, after the end of the subway operation every day, the safety circuit is checked and maintained, after eliminating the fault, the reset operation is performed to start the reset switch, and the shield door safety circuit fault detection and control device provided in the embodiment of the present application is restored to the default state.

[0086] In one embodiment, a door controller DCU and a door state indicator lamp are arranged on each shield door, and the door state indicator lamp is connected with the door controller DCU. The door controller is used to control the shield door action, and the action mode includes but is not limited to: performing an opening door action, performing a closing door action, maintaining an opening door state, and maintaining a closing door state. Figure 3 As shown in the figure, the shield door safety circuit fault detection and control device provided in the embodiment of the present application further comprises a fourth voltage detection unit A4 and a fifth voltage detection unit A5. For each shield door, a fourth voltage detection unit A4 is connected at both ends of the travel switch on the left door, and a fifth voltage detection unit A5 is connected at both ends of the travel switch on the right door. The output terminals of the fourth voltage detection unit A4 and the fifth voltage detection unit A5 are connected with the door controller DCU. The fourth voltage detection unit A4 is used to detect whether the on-off state of the travel switch on the left door of the shield door is open or closed. The fifth voltage detection unit A5 is used to detect whether the state of the travel switch on the right door of the shield door is open or closed. The door controller DCU is used to control the door state indicator lamp to indicate the shield door closing fault in a preset display mode when the shield door maintains the closing door state, if it is detected that the travel switch on the left door of the shield door is open and / or the travel switch on the right door is open.

[0087] The fourth voltage detection unit A4 and the fifth voltage detection unit A5 are both optocoupler relays. The two input terminals of the fourth voltage detection unit A4 are connected to the two terminals of the left door travel switch of the shielded door, the first output terminal of the fourth voltage detection unit A4 is connected to a voltage source, and the second output terminal is connected to the door controller DCU. The two input terminals of the fifth voltage detection unit A5 are connected to the two terminals of the right door travel switch of the shielded door, the first output terminal of the fifth voltage detection unit A5 is connected to a voltage source, and the second output terminal is connected to the door controller DCU.

[0088] In the above embodiment, as shown in Figure 3 , for each shielded door Figure 3 only one shielded door is shown, in fact Figure 3 all shielded doors on the same side are included, and other shielded doors are not marked), the two switches on the left door of the shielded door are connected in series, and the two terminals are connected to the input terminals of the fourth voltage detection unit A4. The fourth voltage detection unit A4 detects the on-off state of the travel switch by detecting the voltage between the left door travel switches. Similarly, the two travel switches on the right door of the shielded door are connected in series, and the two terminals are connected to the input terminals of the fifth voltage detection unit A5. The fifth voltage detection unit A5 detects the on-off state of the travel switch by detecting the voltage between the right door travel switches. The first output terminals of the fourth voltage detection unit A4 and the fifth voltage detection unit A5 are not shown in Figure 3 .

[0089] The fourth voltage detection unit A4 and the fifth voltage detection unit A5 detect the on-off state of the travel switch by detecting the voltage between the two terminals of the travel switch. When the travel switch is closed, the two terminals of the travel switch are at the same potential, the voltage detection unit is not turned on, and outputs a low level. When the travel switch is open, the two terminals of the travel switch are equivalent to a megohm resistor and a small current, so the voltage between the two terminals of the travel switch can be measured. At this time, the voltage detection unit is turned on and outputs a high level.

[0090] A door controller DCU is provided on each shielded door, which is used to control the action of the shielded door, including controlling the shielded door to open, close, maintain the open state, maintain the closed state, etc. A door status indicator lamp is also provided on the shielded door, which is connected to the door controller DCU and is used to indicate the status of the shielded door.

[0091] When the door controller DCU controls the shielded door to maintain the closed state, or detects that the shielded door has been closed to the position and enters the closed state, the detection results of the fourth voltage detection unit A4 and the fifth voltage detection unit A5 are obtained. When the fourth voltage detection unit A4 and / or the fifth voltage detection unit A5 output a high level, it indicates that there is a situation that the travel switch on the shielded door is open. At this time, the door controller DCU controls the door status indicator lamp to display in a preset manner to indicate that the shielded door is closed.

[0092] Wherein, the fault display mode should be distinguished from the display mode when the shielding door is normal. For example, when the shielding door is normal, the door state indicator light can be displayed as always on when the shielding door is opened and remains in the opened state, the door state indicator light can be displayed as 1hz flashing when the shielding door is closed, and the door state indicator light can be extinguished when the shielding door remains in the closed state. When the shielding door closing fault is detected, the door state indicator light can be displayed as 0.5hz flashing, and so on. Thus, the staff is prompted to carry out maintenance.

[0093] It should be noted that the circuit connection mode of each circuit module of the shielding door safety circuit fault detection and control device provided in the embodiment and the selection of the device can be determined according to the actual situation, and the embodiment does not make specific limitations. The function of the shielding door safety circuit fault detection and control device provided in the embodiment is mainly realized through the circuit connection relationship between each circuit module, and does not depend on the program module in a certain circuit module for realization. In addition, each circuit module can be realized through an analog circuit or a digital circuit, and for the circuit module which can implant a program module, the realization of the module function can be realized through the program module provided by the prior art.

[0094] Those skilled in the art can understand that the drawings are only a schematic diagram of a preferred implementation scenario, and the modules or processes in the drawings are not necessarily necessary for implementing the present application. Those skilled in the art can understand that the modules in the device in the implementation scenario can be distributed in the device in the implementation scenario according to the description of the implementation scenario, or can be changed and located in one or more devices different from the implementation scenario. The modules of the above implementation scenario can be combined as one module, or can be further split into multiple sub-modules.

[0095] The above application serial number is only for description, not representing the advantages and disadvantages of the implementation scenario. The above disclosure is only a few specific implementation scenarios of the present application, but the present application is not limited to this. Any changes that can be thought of by those skilled in the art should fall within the protection scope of the present application.

Claims

1. A shielded door safety circuit failure detection and control device, characterized by, The device is used for detecting and controlling the safety circuit of the multiple shield doors on the same side of the platform, the travel switches on the left doors of each shield door are connected in series to obtain a first circuit, the travel switches on the right doors of each shield door are connected in series to obtain a second circuit, the safety circuit comprises the first circuit, the second circuit and a safety relay unit, the first circuit is connected between the power positive pole of the safety relay unit and a first input end, the second circuit is connected between a second input end of the safety relay unit and a power negative pole; the device comprises: a voltage detection module, configured to detect a first voltage between the first input end and the second input end of the safety relay unit, a second voltage between the power positive pole and the first input end of the safety relay unit, and a third voltage between the second input end and the power negative pole of the safety relay unit; a first relay unit connected between the power positive pole and the first input end of the safety relay unit, the contact of the first relay unit being normally open; a second relay unit connected between the second input end and the power negative pole of the safety relay unit, the contact of the second relay unit being normally open; wherein, when the first voltage is lower than a preset first threshold value and the second voltage or the third voltage reaches a preset second threshold value, the first relay unit and the second relay unit are both closed.

2. The apparatus of claim 1, wherein, The device further comprises a control module, and the voltage detection module comprises a first voltage detection unit, the first voltage detection unit being an optical coupling relay; the input end of the first voltage detection unit is connected with the first input end and the second input end of the safety relay unit, the first output end of the first voltage detection unit is connected with a voltage source, and the second output end is connected with the control module; wherein, the first voltage detection unit is configured to detect the first voltage, and when the first voltage reaches the first threshold value, the first output end and the second output end of the first voltage detection unit are turned on.

3. The apparatus of claim 2, wherein, The device further comprises a third relay unit, a fourth relay unit and a fifth relay unit, the third relay unit, the fourth relay unit and the fifth relay unit each comprise two groups of relays, the two groups of relays of the third relay unit each being a single-pole double-throw relay; the voltage detection module further comprises a second voltage detection unit and a third voltage detection unit, the second voltage detection unit and the third voltage detection unit each being an optical coupling relay; the first input end of the second voltage detection unit is connected with the power positive pole of the safety relay unit, the second input end of the second voltage detection unit is connected with the common end of the first group of relays of the third relay unit, the first output end of the second voltage detection unit is connected with a voltage source, and the second output end of the second voltage detection unit is connected with the control module; The first input end of the third voltage detection unit is connected with the common end of the second group of relays in the third relay unit, the second input end of the third voltage detection unit is connected with the negative electrode of the power supply of the safety relay unit, the first output end of the third voltage detection unit is connected with the voltage source, and the second output end of the third voltage detection unit is connected with the control module; In the third relay unit, the normally closed end of the first group of relays is connected with the first end of the first group of relays in the fourth relay unit, and the normally open end of the first group of relays is connected with the first end of the second group of relays in the fourth relay unit; In the third relay unit, the normally closed end of the second group of relays is connected with the first end of the second group of relays in the fourth relay unit, and the normally open end of the second group of relays is connected with the first end of the first group of relays in the fourth relay unit; In the fourth relay unit, the second end of the first group of relays is connected with the first end of the first group of relays in the fifth relay unit, and the second end of the second group of relays is connected with the first end of the second group of relays in the fifth relay unit; In the fifth relay unit, the second end of the first group of relays is connected with the first input end of the safety relay unit, and the second end of the second group of relays is connected with the second input end of the safety relay unit; The control end of the third relay unit, the control end of the fourth relay unit and the control end of the fifth relay unit are all connected with the control module, the contact of the fourth relay unit is normally open, and the contact of the fifth relay unit is normally closed.

4. The device according to claim 3, wherein One end of the first loop is connected with the positive electrode of the power supply of the safety relay unit, the other end is connected with the first input end of the safety relay unit through the first group of relays in the fifth relay unit, and a plurality of travel switches in the first loop are connected in series between the positive electrode of the power supply of the safety relay unit and the first end of the first group of relays in the fifth relay unit; One end of the second loop is connected with the second input end of the safety relay unit through the second group of relays in the fifth relay unit, the other end is connected with the negative electrode of the power supply of the safety relay unit, and a plurality of travel switches in the second loop are connected in series between the negative electrode of the power supply of the safety relay unit and the first end of the second group of relays in the fifth relay unit.

5. The apparatus of claim 4, wherein, The device further comprises a first current-limiting resistor and a second current-limiting resistor; One end of the first current-limiting resistor is connected with the normally open end of the second group of relays in the third relay unit, and the other end of the first current-limiting resistor is connected with the first end of the first group of relays in the fourth relay unit; One end of the second current-limiting resistor is connected with the normally open end of the first group of relays in the third relay unit, and the other end of the second current-limiting resistor is connected with the first end of the second group of relays in the fourth relay unit.

6. The device according to claim 4, wherein when the first voltage is lower than the first threshold value, the fourth relay unit is closed, after the fourth relay unit is closed, the second voltage detection unit detects the second voltage, and the third voltage detection unit detects the third voltage; wherein, when the second voltage reaches the second threshold value, the first output end and the second output end of the second voltage detection unit are turned on; and when the third voltage reaches the second threshold value, the first output end and the second output end of the third voltage detection unit are turned on.

7. The device of claim 6, wherein, when the second voltage or the third voltage reaches the second threshold value, the fifth relay unit is disconnected, and the third relay unit is switched to connect the second voltage detection unit in series with the second loop and the third voltage detection unit in series with the first loop; wherein, when all the travel switches in the first loop are closed and the resistance of the travel switches in the first loop is less than a sensitivity threshold value, the first output end and the second output end of the third voltage detection unit are turned on; and when all the travel switches in the second loop are closed and the resistance of the travel switches in the second loop is less than the sensitivity threshold value, the first output end and the second output end of the second voltage detection unit are turned on; when the second voltage detection unit is turned on and / or the third voltage detection unit is turned on, the first relay unit and the second relay unit are both closed.

8. The apparatus of claim 7, wherein, The device further comprises a conversion switch, the conversion switch being provided with a first conversion position and a second conversion position, and the conversion switch being connected to the control module; when the conversion switch is converted to the first conversion position, the second relay unit is closed when the third voltage detection unit is turned on; the first relay unit is closed when the second voltage detection unit is turned on; when the conversion switch is converted to the second conversion position, the first relay unit and the second relay unit are both closed when the second voltage detection unit is turned on or the third voltage detection unit is turned on.

9. The apparatus of claim 8, wherein, The device further comprises a reset switch, the reset switch being connected to the control module, wherein the reset switch is used to send a reset signal in response to a reset operation to make each relay unit return to a default state.

10. The apparatus of claim 1, wherein, Each shielding door is provided with a door controller and a door state indicator lamp, the door state indicator lamp being connected to the door controller, and the door controller being used to control the action of the shielding door, the action modes including: performing an opening action, performing a closing action, keeping an open door state, and keeping a closed door state; the device further comprises a fourth voltage detection unit and a fifth voltage detection unit; For each shielding door, a travel switch on the left door is connected to one fourth voltage detection unit, and a travel switch on the right door is connected to one fifth voltage detection unit, and the output end of the fourth voltage detection unit and the output end of the fifth voltage detection unit are both connected to the door controller; the fourth voltage detection unit is used to detect whether the on-off state of the travel switch on the left door of the shielding door is disconnected or closed; The fifth voltage detection unit is configured to detect whether the on-off state of the upstroke switch of the right door of the shielding door is open or closed. The door controller is configured to, when the shielding door is in the closed state, control the door state indicator to indicate a closed door failure of the shielding door in a preset display mode if it is detected that the left door upstroke switch and / or the right door upstroke switch is open.

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