STSARCES - Standards for Safety Related Complex Electronic Systems

STSARCES project

S T S A R C E S : Standards for Safety Related Complex Electronic Systems

This project answers to a dedicated call for research in support to European Standardisation issued by the « Standard, Measurement and Testing » Programme. STSARCES examines the validation aspects of safety-related parts of control systems for machinery with regards to the problems encountered with modern electronic and programmable electronic technologies. This research was carried out by 11 research organisations, notified bodies and manufacturers from 6 countries of the EU through a range of related issues, including software and hardware validation, to assist in the development of pr EN 954-2 “Safety of machinery, Safety related parts of control systems, part 2 validation”.

This report develops a framework for harmonized validation procedures, which should be standardised by CEN/CENELEC. The methodology is based on the overall safety lifecycle concept of a system, which is quite new in the field of the machinery sector, and covers both hardware and software. A significant part of the report deals with the software lifecycle, since it is not developed in EN 954.

The Markov modelling approach, also innovative when applied to the field of the machinery, has revealed very successful. The immense influence of the diagnostic coverage could be demonstrated and data on appropriate on-line test intervals for dedicated architectures, combined with realistic MTTF values, are provided and justified. This information provides fundamental advice for the system designer as well as hints for the persons carrying out the evaluations.

Attention has been given to prevent divergences from the requirements of the IEC 61508 since this norm has basic safety publication status. As a positive repercussion, STSARCES determines the validation methods of Programmable Electronic Systems in their uses for safety functions both in EN 954 and draft IEC 62061, a machine application standard derived from IEC 61508. It does allow defining credible and understandable links between categories (EN 954) and safety integrity levels or SILs (draft IEC 62061). This connection is indispensable during the design and development phases of control circuits for the machinery which make use of components based on the category concept, like mechanical, hydraulic, pneumatic, electro-mechanical ones, and PES better characterised by SIL concept.

An extensive presentation of the almost definitive results to ensure their wide acceptance by manufacturers has been carried out at the occasion of the International Conference on « Safety of Industrial Automated Systems », Montreal, October 1999. Thanks to its Organizing Committee, several sessions could be chaired by STSARCES members. The obtained feedback has influenced the presentation of this report, structured as a comprehensive guided tour through the lifecycle of systems, and with more deeply detailed technical contributions transferred to the annexes.

The STSARCES project comprises

The final report of STSARCES project and its annexes

Annex 1  : Software engineering tasks - Case tools
Annex 2  : Software quality and safety requirements
Annex 3  : Guide to evaluating software quality and safety requirements
Annex 4  : Guide for the construction of software tests
Annex 5  : Common mode faults in safety systems
Annex 6  : Quantitative Analysis of Complex Electronic Systems using Fault Tree Analysis and Markov Modelling
Annex 7  : Methods for fault detection
Annex 8  : Safety Validation of Complex Components - Validation by Analysis
Annex 9  : Validation of complex components : Intercomparison black box/white box tests
Annex 10 : Safety Validation of Complex Components - Validation Tests
Annex 11 : Applicability of IEC 61508 & EN 954. Task 1 : A study of the links and divergences between IEC 61508 and EN 954.
Annex 12 : Task 2 : Machine Validation Exercise
Annex 13  : Task 3 : Design Process Analysis
Annex 14  : ASIC development and validation in safety components

Download the files in PDF

Final report of STSARCES project 

Annex 1  : Software engineering tasks - Case tools
Annex 2  : Software quality and safety requirements
Annex 3  : Guide to evaluating software quality and safety requirements
Annex 4  : Guide for the construction of software tests
Annex 5  : Common mode faults in safety systems
Annex 6  : Quantitative Analysis of Complex Electronic Systems using Fault Tree Analysis and Markov Modelling
Annex 7  : Methods for fault detection
Annex 8  : Safety Validation of Complex Components - Validation by Analysis
Annex 9  : Validation of complex components : Intercomparison black box/white box tests
Annex 10 : Safety Validation of Complex Components - Validation Tests
Annex 11 : Applicability of IEC 61508 & EN 954. Task 1 : A study of the links and divergences between IEC 61508 and EN 954.
Annex 12 : Task 2 : Machine Validation Exercise
Annex 13  : Task 3 : Design Process Analysis
Annex 14  : ASIC development and validation in safety components