A Study on Development of Fault diagnosis system for PLC self-diagnostics and its external devices

PLC 자체 고장진단과 그의 외부 소자의 고장 진단 시스템 개발에 관한 연구

  • 허윤기 (포항 종합 제철 기술연구소) ;
  • 변중남 (KAIST 전기 및 전자공학과)
  • Published : 1996.07.22

Abstract

In this paper, a fault diagnosis method is proposed for self-diagnostics of PLC(Programmable Logic Controller), process controller in industrial fields, and diagnosis of its external devices such as sensors and actuators. The aim of this research is proposition of systematic method of fault diagnosis of PLC control system and development of its equipment. A PLC fault diagnosis algorithm consists of self-diagnostics given by PLC makers, Inpuot/Output tracking method by analyzing sequence PLC programs, searching method of past fault cases in database using an expert system, and diagnosis of PLC units such as CPU, DI, and DO board. Finally usability of PLC fault diagnostic system is verified by testing a MELSEC PLC.

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