Dependability of safety-critical systems: contribution of the synchronous approach

In order to develop “critical” programmed protection systems, dedicated development tools are needed. The formalisms used should guarantee a high level of safety for the process being considered. The synchronous approach has numerous advantages which help it meet this target. This article presents the synchronous approach from an industrial point of view. This is the point of view behind the industrial development strategy for critical software within Schneider-Electric´s Safety Electronics and Systems department. The article gives a historical outline and a simple definition of the synchronous approach, followed by a very simple example of an application which demonstrates the advantages of the synchronous approach. It does not give a detailed description of the techniques for proving operational safety, but rather aims to describe as simply as possible, the characteristics of the synchronous approach related to operational safety