Proceedings of the Korean Nuclear Society Conference (한국원자력학회:학술대회논문집)

Korean Nuclear Society (한국원자력학회)
권호 표지

A Formal Safety Analysis for PLC Software-Based Safety Critical System using Z

  • Koh, Jung-Soo (Nuclear Regulatory Inspection Division Korea Institute of Nuclear Safety(KINS)) ;
  • Seong, Poong-Hyun (Department of Nuclear Engineering Korea Advanced Institute of Science and Technology(KAIST)) ;
  • Son, Han-Seong (Department of Nuclear Engineering Korea Advanced Institute of Science and Technology(KAIST))
  • Published : 1997.05.01
Download PDF
⟨ Previous Next ⟩

Abstract

This paper describes a formal safety analysis technique which is demonstrated by performing empirical formal safety analysis with the case study of beamline hutch door Interlock system that is developed by using PLC(Programmable Logic Controller) systems at the Pohang Accelerator Laboratory. In order to perform formal safety analysis, we have built the Z formal specifications representation from user requirement written in ambiguous natural language and target PLC ladder logic, respectively. We have also studied the effective method to express typical PLC timer component by using specific Z formal notation which is supported by temporal history. We present a formal proof technique specifying and verifying that the hazardous states are not introduced into ladder logic in the PLC-based safety critical system.

Keywords