DC two-wire proximity sensor fault detection circuit

Abstract

The invention provides a DC two-wire proximity sensor fault detection circuit, which detects the working current of the two-wire proximity switch sensor, judges the working state of the sensor and the open-short circuit fault, and outputs the corresponding signal, thereby effectively solving the problem of detection The equipment cannot judge the fault of the sensor, and there is a leakage current in the output of the DC two-wire proximity sensor, and the residual voltage of the signal causes the level to be unstable, and the detection equipment cannot recognize the problem. This circuit can be placed between the sensor and the control equipment (such as PLC), output the fault output signal to the PLC or alarm system and other equipment, and make an alarm or emergency stop for the sensor fault, so as to effectively avoid the accident caused by the sensor fault. production accident. Compared with the prior art, the sensor signal processed by the circuit of the invention has no residual voltage and leakage current, and has better compatibility.

Description

technical field [0001] The invention relates to a proximity sensor, in particular to a DC two-wire type proximity sensor fault detection circuit. Background technique [0002] Proximity sensors are sensors that replace contact detection methods such as limit switches and are designed to perform detection without touching the detection object. The main object of its detection is a metal object. When the detected object is close to the sensing surface of the switch to the action distance, the switch can be activated without mechanical contact and any pressure, thereby driving DC electrical appliances or providing control for computer (PLC) devices. instruction. It has the advantages of reliable action, stable performance, fast frequency response, long application life, strong anti-interference ability, etc., and is widely used in machine tools, metallurgy, chemical industry, textile and printing industries. [0003] At present, proximity sensors can be divided into inductive...

AI Technical Summary

Problems solved by technology

[0004] For this reason, the purpose of the present invention is to provide a DC two-wire proximity sensor fault detection circuit to solve the problem that the drive equipment cannot judge the sensor fault, and there is a leakage current in the output of the DC two-wire proximity sensor, and the residual voltage of the signal causes the level to be unstable. , to detect problems that the device does not recognize

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