A semiconductor dry and wet contact fault diagnosis circuit and diagnosis method

Abstract

The invention discloses a semiconductor dry-wet contact fault diagnosis circuit which comprises a semiconductor switching tube U2_1, a dry-wet contact Q1_1 and a semiconductor switching tube U3_1. Aninput end of the semiconductor switching tube U2_1 is used for receiving a driving signal, and an output end of the semiconductor switching tube U2_1 is used for controlling the switch-on and switch-off of the dry-wet contact Q1_1. An input end of the semiconductor switching tube U3_1 is connected to the dry-wet contact Q1_1, and an output end of the semiconductor switching tube U3_1 outputs a feedback signal. When the dry-wet contact Q1_1 is switched on, the output end of the semiconductor switching tube U3_1 outputs an effective feedback signal. A dry-wet contact judgment method of the invention is simple, a control chip judges whether a dry contact is normal through comparing the states of a driving signal and the feedback signal, if the driving signal and the feedback signal exist or do not exist at the same time, the dry contact is judged to be normal, and if the effective states of the driving signal and the feedback signal are inconsistent, the fault of the dry contact can be determined.

Description

technical field [0001] The invention relates to the field of logic control of rail transit vehicle equipment, in particular to a semiconductor dry and wet contact fault diagnosis circuit and a diagnosis method. Background technique [0002] Traditional dry and wet contacts usually use electromagnetic relays. However, with the improvement of reliability requirements, such as on-board control equipment for rail transit that is related to personal safety, the inherent high failure rate of relays can no longer meet the needs of high reliability. Began to use semiconductor logic control unit (LCU) to replace the traditional electromagnetic relay solution. [0003] In the existing LCU system, semiconductor devices with obvious reliability advantages are used to replace traditional time relays and intermediate relays for both input and output. The input circuit performs photoelectric isolation sampling of 110V input and sends it to the control chip for processing. The drive signal...

AI Technical Summary

Problems solved by technology

[0004] However, the detection of dry contact and wet contact in the existing LCU system can only be detected separately. In the prior art, the detection of wet contact must rely on the voltage (+110V) at the front end of the wet contact to achieve output feedback. For dry contact, due to the front end There may be no voltage, so the detection circuit of the wet contact cannot be effectively used; in the prior art, there is no effective solution for the fault diagnosis of the semiconductor dry contact, and the general compromise is the front-end feedback method of the switch tube, but this The defect of this design is that it can only diagnose the failure of the front end of the drive, but it cannot be effectively diagnosed for the failure of the switching tube itself, such as breakdown.

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