Guidelines for the use of Programmable Logic Controllers in Safety-related Systems Edited by

international body of experts in the field of dependable industrial computer systems and focuses its interest on safety, reliability and security. The Programmable Logic Controllers (PLC) Working Group was set up within EWICS TC7 in 1992. Throughout its life-span the Group attracted attention of more than twenty experts from ten countries. The members are from industry, universities and government institutions. The main industries represented include transportation, process control and atomic energy. Government agencies include regulatory, assessment and testing authorities. The utilization of PLCs in safety-related Systems (SrS) is receiving much favour amongst industry. The need for good engineering practices in this area is a vital tool for the industrial users not only in the European Community. This guideline addresses important areas in the use of PLCs in SrS for hazardous processes, such as global requirements, specifications, procurement, hardware and software design, implementation, verification, validation, security, operations, maintenance, and documentation. References are provided to allow the reader to review issues in greater depth. The guideline is intended for person