Current acquisition and diagnosis circuit and failure diagnosis method thereof

Abstract

The invention provides a current acquisition and diagnosis circuit which comprises a current signal input end CH1, a sampling unit, a signal amplification unit and an analog signal-to-digital signal converter ADC. The current acquisition and diagnosis circuit is characterized in that the signal amplification unit comprises a plurality of signal conditioning operational amplifiers which are connected in parallel, the signal amplification unit is further connected with a current source in parallel, the current signal input end CH1 is connected with a detection unit, and the detection unit is connected to the analog-to-digital signal converter ADC. The invention further provides a failure diagnosis method of the circuit. The failure diagnosis method comprises the following steps: performing failure diagnosis on the switch SW1, the switch SW18 and the switch SW3; performing failure diagnosis on the analog signal-to-digital signal converter ADC, the signal conditioning operational amplifierOP1 and the signal conditioning operational amplifier OP2; carrying out failure diagnosis on the power supply I1 and the switch SW17; and performing failure diagnosis on the sampling resistor R1 andthe sampling resistor R9. The current acquisition and diagnosis circuit and the failure diagnosis method thereof have a relatively high self-diagnosis function and can detect failures of all devices in the current acquisition circuit and are high in diagnosis coverage rate.

Description

technical field [0001] The invention relates to the technical field of current acquisition, in particular to a current acquisition diagnosis circuit and a failure diagnosis method thereof. Background technique [0002] The current signal acquisition system on the industrial site is the most important input component in industrial control systems such as DCS and SIS. The current signal acquisition circuit will involve device failure, especially in failure protection devices, such as in automation technology, reliable devices Failure detection plays an important role. On the one hand, the safety of the process must be ensured, and on the other hand, the physical and life safety of, for example, the personnel operating the process must be ensured. [0003] However, current current signal acquisition systems have low diagnostic coverage, low safety, and poor usability for current signal acquisition circuits. The voltage of the voltage reference is used to detect the accuracy o...

AI Technical Summary

Problems solved by technology

[0004] The invention solves the problems of low diagnostic coverage, low safety, and poor usability of the current signal acquisition circuit in the prior art, and proposes a current acquisition diagnostic circuit and its failure diagnosis method, which diagnoses each of the ADCs through voltage scanning. A sampling code value, through the dynamic description of the reference current to diagnose the drift of the resistance itself does not exceed the accuracy

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