Digital value acquisition circuit with fault diagnosis capacity

Abstract

The invention discloses a digital value acquisition circuit with fault diagnosis capacity. The digital value acquisition circuit comprises a contact type switch for information to be acquired and a fault judgment system for judging whether an acquisition process is abnormal or not according to output results of the two signal acquisition circuits, wherein the contact type switch is connected with a signal acquisition circuit A and a signal acquisition circuit B. The two acquisition circuits simultaneously execute signal acquisition on the same object; and whether the current sampling circuit has a fault or not is judged according to a result whether the two paths of acquired signals are the same or different is judged, so that a prevention measure can be made in advance, and the aim of improving the self-diagnosis coverage rate is fulfilled. The digital value acquisition circuit can acquire normal signals; and furthermore, hardware is subjected to random failure, the acquisition circuit can intelligently output a corresponding fault state, so that a fault diagnosis effect and a guide security treatment can be achieved, and the completeness of a system security function can be guaranteed.

Description

technical field [0001] The invention relates to a signal acquisition circuit, in particular to a digital quantity acquisition circuit capable of identifying signal faults of equipment to be acquired. Background technique [0002] In an industrial control system (such as DCS or PLC), the status of switching signals such as the start and stop of equipment at all levels, process control, physical quantity threshold status, and fault alarms have an important impact on the operation and safety of the entire system. The acquisition and recording of signals is also particularly important. Therefore, it is usually necessary to design a digital signal acquisition card to collect and report these signals, so that the main control system can make corresponding control and protection outputs according to the collected signal status, so that the entire DCS system is in a safe state. Based on the safety isolation of the on-site switching signal and the DCS control system, and the necessi...

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Problems solved by technology

[0004] In order to solve the problem that the digital quantity acquisition circuit in the prior art cannot realize fault diagnosis, the present

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