A safety circuit diagnosis circuit and screen door control system

Abstract

The application discloses a safety loop diagnosis circuit and a shielded door control system. The safety loop diagnosis circuit includes a diagnosis circuit power supply, a plurality of signal isolation circuits, a signal sampling circuit connected to the plurality of signal isolation circuits, and a signal sampling circuit connected to the signal isolation circuits. A control unit connected to the sampling circuit, wherein: the diagnostic circuit power supply includes an isolated power supply and a power distribution switch connected in series at any end of the isolated power supply, and the power distribution switch is used to switch the positive pole line of the safety circuit to connect The isolated power supply and the negative line of the safety circuit are connected to the two states of the isolated power supply; after the current flowing from the positive pole of the diagnostic circuit power supply passes through any normally open contact on the safety circuit, it can The signal flows back to the negative pole of the diagnostic circuit power supply through different signal isolation circuits, so that when any two-way limit switch fails due to an abnormal normally open contact, the fault point can be quickly confirmed.

Description

technical field [0001] The invention relates to the technical field of development of a screen door control system, in particular to a safety loop diagnosis circuit and a screen door control system. Background technique [0002] The safety circuit is an electrical circuit used in the screen door control system to judge whether all the screen doors of the platform are fully closed and locked. Its circuit structure is as follows: figure 1 As shown, it mainly includes relay KA1, safety relay group KA2, safety loop power supply E1 and N double-way limit switches. Specifically: each screen door adopts several double-way limit switches to monitor the closing of the screen door In the locked state, each double-way limit switch includes one normally open contact S and one normally closed contact. The N normally open contacts S are divided into two groups, and one group is connected in series to the positive line of the safety circuit (ie The line connected between the positive pole...

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Problems solved by technology

[0003] The N normally closed contacts are all connected to the state detection circuit in the screen door control system, and the control unit in the state detection circuit can automatically diagnose the normal state when any normally closed contact is abnormally closed or abnormally opened. The two-way limit switch corresponding to the closed contact is the fault point, but when any one of the two-way limit switches fails due to abnormality of the normally open contact S (such as abnormal open circuit), it is impossible to rely on the state detection circuit to automatically confirm the fault point, but only through manual investigation method, the labor intensity of personnel is high and the efficiency is low

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