The functions needed to provide the necessary diagnostic coverage have been included in the design At SIL 3 and above If a communication protocol has been specified formally in the requirements specification then the software design will be based on that formal representation and not on any natural language interpretation of the formal design. Note: If the IEC 61508-2 and IEC 61508-3 assessments are conducted by different persons or teams then the assessors are required to agree that this ToE has been met. 17 Self To ensure that the design 7.4.2.7 For all safety integrity levels ensure that monitoring shall include, there is evidence that the design: and commensurate with the diagnostics required , self-monitoring Includes elements for the specified of control flow and data and diagnostics functions flow. On failure detection, specified in the software safety requirements specification. appropriate actions shall be taken Includes software self-monitoring e.g. watchdogs, windowed watchdogs, sequence of event monitoring, data corruption monitoring. Timeliness of monitoring of safety integrity functions and detection of faults, for high and low demand systems
The functions needed to provide the necessary diagnostic coverage have been included in the design At SIL 3 and above If a communication protocol has been specified formally in the requirements specification then the software design will be based on that formal representation and not on any natural language interpretation of the formal design. Note: If the IEC 61508-2 and IEC 61508-3 assessments are conducted by different persons or teams then the assessors are required to agree that this ToE has been met. 17 Self monitoring and diagnostics To ensure that the design shall include, commensurate with the required , self-monitoring of control flow and data flow. On failure detection, appropriate actions shall be taken 7.4.2.7 For all safety integrity levels ensure that there is evidence that the design: Includes elements for the specified and diagnostics functions specified in the software safety requirements specification. Includes software self-monitoring e.g. watchdogs, windowed watchdogs, sequence of event monitoring, data corruption monitoring. Timeliness of monitoring of safety integrity functions and detection of faults, for high and low demand systems
CASS_TOES_for_software_assessment_IEC_61508-3_2010_-_ABRIDGED_v1.docx