欧洲铁路信号规格EN50128

EN 50126-i addresses system issues on the widest scale, while EN 50129 addresses the approval process for individual systems which can exist within the overall railway control and protection system. This European Standard concentrates on the methods which need to be used in order to provide software which meets the demands for safety integrity which are placed upon it by these wider considerations This European Standard provides a set of requirements with which the development deployment and maintenance of any safety-related software intended for railway control and protection applications shall comply. it defines requirements concerning organisational structure, the relationst\ip between organisations and division of responsibility involved in the development. deployment and maintenance activities. Criteria for the qualification and expertise of personnel are also provided in this European Standard. The key concept of this European Standard is that of levels of software safety integrity. This European Standard addresses five software safety integrity levels where 0 is the lowest and 4 the highest one. The higher the risk resultin 9 from software failure, the higher the software safety integrity level. will be This European Standard has identified techniques and measures for the five levels of software safety integrity The Required techniques and measures for software safety integrity levels 0-4 are shown in the normative tables of Annex A In this version the required techniques for level 1 are the same as for level 2. and the required techniques for level 3 are the same as for level 4. This European Standard do•s not give guidance on which level of software safety inte9 *ity is appropriate for a g iven risk. This decision will depend upon many factors including the nature of the application. the extent to which other systems carry out safety functions and social and economic factors.