Validation of communication safety critical control systems (NT TR 543)

Abstract

  The purpose of this technical report is to provide a support to testing laboratories and industry constructors in designing and validating safety in distributed control systems. The report contains a summary of the basic characteristics and concepts specific to distributed systems as well as a description of the components e.g. bus systems and communication protocols. The activities carried out under the different life cycle phases of dependable distributed systems are covered. The concepts of EN 954 and IEC 61508 standards are combined and the user of this work may find information related to his specific needs without being compelled to consult the whole document. The scope of all the fault types that must be considered during system specification and design is treated. Measures and techniques to detect, avoid, or contain errors and/or to initiate a transition to a safe-state are assessed according to the V-model at each system level and at each respective phase of development. A summary of risks and evaluation of protective methods is suggested for the protocol and bus levels. However a complete evaluation of the safety integrity level for a distributed system requires consultation of either IEC 61508 or EN 954 standard or any other application specific standards.