Fault-safe contactless output circuit conforming to SIL4 safety level

Abstract

The invention, which relates to the technical field of the circuit, discloses a fault-safe contactless output circuit conforming to an SIL4 security level, comprising a second module and a first module. The first module comprises a first CPU, a first output driving module and a first execution unit, the first output driving module comprises a push-pull circuit, a high-frequency transformer, a rectifying circuit and a first driver which are electrically connected in sequence, and the second module comprises a second CPU, a second output driving module and a second execution unit. The second output driving module comprises a second driver, the second driver comprises an MOSFET driving chip, and the second execution unit comprises a second output circuit MOS tube; the system has the advantages that the service life of the logic control system is prolonged, the reliability of the logic control system is improved, and the system is maintenance-free, energy-saving and environment-friendly.

Description

technical field [0001] The present invention relates to the technical field of circuits, and more particularly, the present invention relates to a fail-safe contactless output circuit conforming to SIL4 safety level. Background technique [0002] At present, most of the safety output circuit designs that meet the SIL4 safety level adopt safety relay or safety AND gate circuit design. The acquisition circuit collects the output of safety relay contacts or safety AND gate for fault diagnosis. Of course, this design can meet SIL4 requirements. But there are certain deficiencies. As follows: First, the failure rate of relays and safety and gate circuits is high. According to the statistical analysis of vehicle control failures, it is found that more than 60% of the failures are caused by relay failures; Second, the relay action has mechanical stress, high temperature and vibration. The operating environment and long-term continuous work can easily lead to mechanical fatigue, re...

AI Technical Summary

Problems solved by technology

As follows: First, the failure rate of relays and safety gate circuits is high. According to the statistical analysis of vehicle control failures, it is found that more than 60% of the failures are caused by relay failures; The operating environment and long-term continuous work will easily lead to mechanical fatigue, resulting in poor contact or adhesion of contacts; third, safety relays are generally imported devices, and the cost of maintenance and replacement is relatively high; There will be jitter and mechanical delay during shutdown, which will transmit interference signals to the lower-level system; fifth, the safety relay and safety gate are large and heavy, which cannot meet the requirements of designing multiple independent channels in a limited space (3U board) Channel Safety Output Circuit Requirements

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