EWICS-98
Guidelines for the Use of Programmable Logic Controllers in Safety-Related Systems
ISBN: REWIC01
Published: 1998

Price: $25.00

This document provides a guideline defining the proper use of Programmable Logic Controllers in Safety-related Systems (safety PLC) according to Safety Integrity Levels (SIL) 1-3 (typically in demand mode, de-energized to trip) as defined in dIEC 1508 [IEC 97] or according to requirements classes 1-6 as defined in DIN V 19250 [DIN 94] in a way that:

• utilizes existing and developing practices, guidelines and standards;
• considers users, procurers, developers, engineering, and certifiers/assessors needs;
• allows a path forward to guideline development for other programmable electronic controllers (e.g. DCSC = distributed control system controller, SLC = single loop control etc.); and
• allows guideline users to implement computer technology to improve safety in their plant.

Higher safety integrity levels such as SIL 4 (IEC) or requirements classes 7/8 (DIN) typically require additional design considerations that are not provided in this guideline.