AADvance Safety Manual - Tuv-fs.com

Chapter 5 AADvance Functional Safety SystemImplementationSequential Function Chart (SFC) Safety Related Languages. The AADvance controller supports acomprehensive set of certified functions. The certified functions set includes themost commonly used function. These tested functions may be used freely in thedevelopment of an application. Further functions may be used subject tocompletion of testing commensurate with the level used for the commonly usedfunctionIL and ST include program flow control functions; these functions shall be usedwith caution to ensure that infinite loop or omitted logic conditions do not result.Where these constructs are used, it is recommended that full branch and datacoverage tests be performed on these sections of program. It is recommended thatonly Boolean conditions be used for these constructs to ensure that a feasible set oftests can be applied.Application programmer generated function blocks may be created either on aproject specific or library basis. Where these functions are to be used for safetyrelatedapplications, they shall be subject to exhaustive testing, commensurate withthat used for the commonly used functions. Once the function block has been subjectto this level of testing it may be used as for commonly used functions.There is provision for the AADvance system to support multiple programs within aproject. A complete project may be classified as safety or non-safety related. A safetyrelatedproject may use only the safety programming languages; non-safetyprogramming languages shall not be used. A project classified as non-safety may use anyof the programming languages and the full instruction set but shall not be used toimplement safety related functions.Testing of New or Previously Untested FunctionsThe AADvance Workbench comprises a number of function blocks that can becombined together to form a project application.The use of these function blocks in a safety certified system is only permittedonce they have been tested for correct operation.The new or previously untested function may be: a generic function block, which forms part of the Workbench, but has notpreviously been subject to the level of testing defined herein, or a project-specific function block, which is written to meet the needs of a particularfeature within an application program, and may comprise a number of genericfunction blocks or other program functions.Document number 553630 Issue 7: February 2010 5-27