Safety turn-off circuit controlled by double relays

Abstract

The utility model discloses a safety turn-off circuit controlled by double relays, which belongs to the field of electrical control, and comprises a travel switch S1, a travel switch S2, a relay KA1, an optical coupler PHC1 and an optical coupler PHC2, one end of the travel switch S1 is connected with 24V voltage, the other end of the travel switch S1 is connected with the anode of a diode D5, the cathode of the diode D5 is connected with the emitter of a triode TR3 and a resistor R9, and the resistor R9 is connected with the relay KA1. The other end of the resistor R9 is connected with the base electrode of the triode TR3 and the resistor R8, the collector electrode of the triode TR3 is connected with the relay K1, and the other end of the resistor R8 is connected with the cathode of the diode ZD2. The safety turn-off circuit controlled by the double relays can reliably turn off a main power supply in an abnormal state, and safety accidents are completely eradicated.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical control, in particular to a double-relay controlled safety shutoff circuit. Background Art

[0002] Nowadays, the degree of automation in industrial production is getting higher and higher, which leads to frequent safety accidents in the production process. In the power system, the safety shutdown circuit can be used to cut off the power supply in time to protect the equipment in the case of power outage, overload, short circuit, etc. This circuit is usually composed of relays or circuit breakers. When an abnormal situation is detected, the circuit breaker will be triggered to cut off the power supply.

[0003] Most existing safety shutdown circuits are controlled by a single switch component. This control method is not very sensitive and may cause repeated actions near the triggering critical point, affecting the service life of the circuit. Utility Model Content

[0004] The purpose of the utility model is to provide a double-relay controlled safety shutdown circuit to solve the problems raised in the above background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A double-relay controlled safety shutdown circuit comprises a travel switch S1, a travel switch S2, a relay KA1, an optical coupler PHC1 and an optical coupler PHC2, wherein one end of the travel switch S1 is connected to a 24V voltage, the other end of the travel switch S1 is connected to an anode of a diode D5, the cathode of the diode D5 is connected to an emitter of a transistor TR3 and a resistor R9, the other end of the resistor R9 is connected to a base of the transistor TR3 and a resistor R8, the collector of the transistor TR3 is connected to a relay K1, the other end of the resistor R8 is connected to a cathode of a diode ZD2, the anode of the diode ZD2 is connected to an optical coupler PHC2, and the optical coupler PHC3 is connected to a relay K1. The collector of the phototransistor inside the coupler PHC2, the emitter of the phototransistor inside the photocoupler PHC2 is connected to the COM port, the anode of the light-emitting diode inside the photocoupler PHC2 is connected to the cathode of the light-emitting diode inside the photocoupler PHC1, the cathode of the light-emitting diode inside the photocoupler PHC2 is connected to the collector of the transistor TR2, the emitter of the transistor TR2 is connected to the anode of the diode D7 and the resistor R11, the cathode of the diode D7 is connected to the travel switch S2, the other end of the travel switch S2 is connected to the COM port, and the base of the transistor TR2 is connected to the resistor R10 and the resistor R11 , the other end of the resistor R10 is connected to the cathode of the diode D6, the anode of the diode D6 is connected to the node T12, the emitter of the phototransistor inside the optocoupler PHC1 is connected to the cathode of the diode ZD1, the anode of the diode ZD1 is connected to the resistor R3, the other end of the resistor R3 is connected to the resistor R6 and the base of the transistor TR1, the emitter of the transistor TR1 is connected to the anode of the diode D4 and the other end of the resistor R6, the collector of the transistor TR1 is connected to the relay K2, the anode of the light-emitting diode inside the optocoupler PHC1 is connected to the resistor R1 and the resistor R4, the other end of the resistor R1 is connected to the Resistor R2, the other end of resistor R2 is connected to the cathode of diode D2, resistor R5 and port 2 of the contact of relay KA1, the anode of diode D2 is connected to the cathode of diode D1 and port 3 of the contact of relay KA1, the other end of resistor R5 is connected to capacitor C1, the other end of capacitor C1 is connected to the other end of resistor R4, the coil of relay KA1, capacitor C2 and the anode of diode D3, the cathode of diode D3 is connected to the anode of diode D1 and node J3-4, the other end of capacitor C2 is connected to resistor R7, and the other end of resistor R7 is connected to port 1 of the contact of relay KA1.

[0007] As a further technical solution of the utility model: the transistor TR1 is an NPN transistor.

[0008] As a further technical solution of the utility model: the transistor TR2 is an NPN transistor.

[0009] As a further technical solution of the utility model: the transistor TR3 is a PNP transistor.

[0010] As a further technical solution of the utility model: the diode ZD1 is a voltage-stabilizing diode.

[0011] As a further technical solution of the utility model: the diode ZD2 is a voltage-stabilizing diode.

[0012] Compared with the prior art, the beneficial effects of the utility model are:

[0013] The utility model discloses a double-relay controlled safety shut-off circuit which can reliably shut off the main power supply in an abnormal state and prevent the occurrence of safety accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the overall circuit principle diagram of the utility model. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0016] See also Figure 1A double-relay controlled safety shutdown circuit is composed of components such as a travel switch S1, a travel switch S2, a relay KA1, an optical coupler PHC1 and an optical coupler PHC2, wherein one end of the travel switch S1 is connected to a 24V voltage, the other end of the travel switch S1 is connected to the anode of a diode D5, the cathode of the diode D5 is connected to the emitter of a transistor TR3 and a resistor R9, the other end of the resistor R9 is connected to the base of the transistor TR3 and a resistor R8, the collector of the transistor TR3 is connected to a relay K1, the other end of the resistor R8 is connected to the cathode of a diode ZD2, and the diode ZD2 The anode of the phototransistor is connected to the collector of the phototransistor in the optocoupler PHC2, the emitter of the phototransistor in the optocoupler PHC2 is connected to the COM port, the anode of the light-emitting diode in the optocoupler PHC2 is connected to the cathode of the light-emitting diode in the optocoupler PHC1, the cathode of the light-emitting diode in the optocoupler PHC2 is connected to the collector of the transistor TR2, the emitter of the transistor TR2 is connected to the anode of the diode D7 and the resistor R11, the cathode of the diode D7 is connected to the travel switch S2, the other end of the travel switch S2 is connected to the COM port, the base of the transistor TR2 is connected to the resistor R10 and the resistor R21. The other end of the resistor R10 is connected to the cathode of the diode D6, the anode of the diode D6 is connected to the node T12, the emitter of the phototransistor inside the optocoupler PHC1 is connected to the cathode of the diode ZD1, the anode of the diode ZD1 is connected to the resistor R3, the other end of the resistor R3 is connected to the resistor R6 and the base of the transistor TR1, the emitter of the transistor TR1 is connected to the anode of the diode D4 and the other end of the resistor R6, the collector of the transistor TR1 is connected to the relay K2, the anode of the light-emitting diode inside the optocoupler PHC1 is connected to the resistor R1 and the resistor R4, the other end of the resistor R1 is connected Connect resistor R2, the other end of resistor R2 is connected to the cathode of diode D2, resistor R5 and port 2 of the contact of relay KA1, the anode of diode D2 is connected to the cathode of diode D1 and port 3 of the contact of relay KA1, the other end of resistor R5 is connected to capacitor C1, the other end of capacitor C1 is connected to the other end of resistor R4, the coil of relay KA1, capacitor C2 and the anode of diode D3, the cathode of diode D3 is connected to the anode of diode D1 and node J3-4, the other end of capacitor C2 is connected to resistor R7, and the other end of resistor R7 is connected to port 1 of the contact of relay KA1.

[0017] Here’s how it works:

[0018] 1. Power on the system and ensure that the travel switches S1 and S2 are in the non-actuated state, the node T12 is at a high level of 24V, the nodes T22 and COM11 are at a low level, the transistor TR2 is turned on, and the C pole of the transistor TR2 is at a low level. Since relays K1 and K2 are not energized, the high level of node T12 makes node J3-4 high through its normally closed contacts 22 and 21. The high level of node J3-4 makes optocouplers PHC1 and PHC2 turn on through diodes D1 and D2 and resistors R2 and R1, and charges capacitor C1. Optocoupler PHC1 is turned on, and 24V passes through voltage regulator ZD1 and resistor R3 to turn on transistor TR1. The collector of transistor TR1 changes node K2- to low level, so that relay K2 is turned on, and normally open contacts 33 and 34 of K2 are closed to form a self-locking loop for relay K2; at the same time, optocoupler PHC2 is turned on, and COM port makes transistor TR3 turn on through voltage regulator ZD2 and resistor R8, and the collector of transistor TR3, that is, K1+, becomes high level, so that relay K1 is turned on, and normally open contacts 33 and 34 of K1 are turned on to form a self-locking loop for K1. Relays K1 and K2 are energized, and their normally open main contacts 63 / 64, 53 / 54, and 43 / 44 are energized to provide a safe output. At this time, the normally closed contacts 22 / 21 of relays K1 and K2 are disconnected, causing node J3-4 to become low level, and relay KA1 is disconnected; capacitor C1 is discharged, and the optocouplers PHC1 and PHC2 are kept on for a short time through resistors R5, R2, and R1 to prevent relays K1 and K2 from being unreliable. After capacitor C1 is discharged, the optocouplers PHC1 and PHC2 are turned off, causing transistors TR1 and TR2 to be turned off. Due to the self-locking circuit, relays K1 and K2 remain energized, and the system is in a safe output state.

[0019] 2. If the travel switch S1 is activated (disconnected) during the safety output process, the T12 node becomes low level, thereby invalidating the self-locking circuit of K1, disconnecting the relay K1, and the system is in a safe shutdown state. At this time, even if the travel switch S1 is reset, since K2 is still in the energized state, the node J3-4 is low level, the optocoupler PHC1, PHC2, transistor TR1, and transistor TR2 cannot be turned on, so K1 cannot be energized, and the system is still in a safe shutdown state. At this time, the travel switch S2 needs to be activated (disconnected) and reset, so that the relay K2 is also disconnected, so that the node J3-4 is high level to open PHC1, PHC2, transistor TR1, and transistor TR2, and the relays K1 and K2 are energized to restore the system to a safe output state.

[0020] 3. If the travel switch S2 is activated (disconnected) during the safety output process, nodes T22 and COM11 become suspended, thereby invalidating the self-locking circuit of K2, disconnecting relay K2, and placing the system in a safe shutdown state. At this time, even if the travel switch S2 is reset, since K1 is still in the energized state, node J3-4 is at a low level, and the optocouplers PHC1, PHC2, transistors TR1, and transistors TR2 cannot be turned on, so K2 cannot be energized, and the system is still in a safe shutdown state. At this time, the travel switch S1 needs to be activated (disconnected) and then reset, so that relay K1 is also disconnected, and node J3-4 is at a high level to turn on PHC1, PHC2, transistors TR1, and transistors TR2, and energize relays K1 and K2 to restore the system to a safe output state.

[0021] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0022] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A double-relay controlled safety shutdown circuit, comprising a travel switch S1, a travel switch S2, a relay KA1, an optical coupler PHC1 and an optical coupler PHC2, characterized in that: One end of the travel switch S1 is connected to a 24V voltage, the other end of the travel switch S1 is connected to the anode of a diode D5, the cathode of the diode D5 is connected to the emitter of the transistor TR3 and the resistor R9, the other end of the resistor R9 is connected to the base of the transistor TR3 and the resistor R8, the collector of the transistor TR3 is connected to the relay K1, the other end of the resistor R8 is connected to the cathode of the diode ZD2, the anode of the diode ZD2 is connected to the collector of the phototransistor inside the optocoupler PHC2, and the emitter of the phototransistor inside the optocoupler PHC2 is connected to CO M port, the anode of the light-emitting diode inside the optocoupler PHC2 is connected to the cathode of the light-emitting diode inside the optocoupler PHC1, the cathode of the light-emitting diode inside the optocoupler PHC2 is connected to the collector of the transistor TR2, the emitter of the transistor TR2 is connected to the anode of the diode D7 and the resistor R11, the cathode of the diode D7 is connected to the travel switch S2, the other end of the travel switch S2 is connected to the COM port, the base of the transistor TR2 is connected to the resistor R10 and the resistor R11, the other end of the resistor R10 is connected to the cathode of the diode D6, the anode of the diode D6 is connected to the resistor R11, and the other end of the resistor R10 is connected to the cathode of the diode D6. The base of the transistor TR1 is connected to the node T12, the emitter of the phototransistor in the optocoupler PHC1 is connected to the cathode of the diode ZD1, the anode of the diode ZD1 is connected to the resistor R3, the other end of the resistor R3 is connected to the resistor R6 and the base of the transistor TR1, the emitter of the transistor TR1 is connected to the anode of the diode D4 and the other end of the resistor R6, the collector of the transistor TR1 is connected to the relay K2, the anode of the light-emitting diode in the optocoupler PHC1 is connected to the resistor R1 and the resistor R4, the other end of the resistor R1 is connected to the resistor R2, and the other end of the resistor R2 is connected The cathode of diode D2, resistor R5 and port 2 of the contact of relay KA1, the anode of diode D2 is connected to the cathode of diode D1 and port 3 of the contact of relay KA1, the other end of resistor R5 is connected to capacitor C1, the other end of capacitor C1 is connected to the other end of resistor R4, the coil of relay KA1, capacitor C2 and the anode of diode D3, the cathode of diode D3 is connected to the anode of diode D1 and node J3-4, the other end of capacitor C2 is connected to resistor R7, and the other end of resistor R7 is connected to port 1 of the contact of relay KA1.

2. A dual-relay controlled safety shutdown circuit according to claim 1, characterized in that: The transistor TR1 is an NPN transistor.

3. A dual-relay controlled safety shutdown circuit according to claim 1, characterized in that: The transistor TR2 is an NPN transistor.

4. A dual-relay controlled safety shutdown circuit according to claim 1, characterized in that: The transistor TR3 is a PNP transistor.

5. A dual-relay controlled safety shutdown circuit according to claim 1, characterized in that: The diode ZD1 is a voltage stabilizing diode.

6. A dual-relay controlled safety shutdown circuit according to claim 1, characterized in that: The diode ZD2 is a voltage stabilizing diode.

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