International Electrotechnical Commission

Railway applications - Communication, signalling and processing systems - Software for railway control and protection systems - Edition 2.0
 N 62279

Annotation

This International Standard specifies the process and technical requirements for the development of software for programmable electronic systems for use in railway control and protection applications. It is aimed at use in any area where there are safety implications. These systems can be implemented using dedicated microprocessors, programmable logic controllers, multiprocessor distributed systems, larger scale central processor systems or other architectures.

This Standard is applicable exclusively to software and the interaction between software and the system of which it is part.

This Standard is not relevant for software that has been identified as having no impact on safety, i.e. software of which failures cannot affect any identified safety functions. The concept of SIL 0 is introduced because uncertainty is present in the evaluation of the risk, and even in the identification of hazards. At least the SIL 0 requirements of this Standard are fulfilled for the software part of functions that have a safety impact below SIL 1.

This Standard applies to all safety related software used in railway control and protection systems, including

– application programming,

– operating systems,

– support tools,

– firmware.

Application programming comprises high level programming, low level programming and special purpose programming (for example: Programmable logic controller ladder logic).