HINTSW - T & T Systems is able to support its customers in the right selection of hardware architectures and also in the software diagnostic test design, implemented with the correct algorithms that ensure compliance with the requirements contained in Appendix H (Annex H) of IEC 60730.
The latest edition (2010) of IEC 60730, Appendix H relating to the electronic controls, unlike previous editions, introduces the concept of tolerance to failure. The approach of this standard remains, however, very different from that of IEC 61508 (General rule regarding the functional safety of electrical / electronic / programmable electronic systems) and from industry standards derived from that (for example: for the process industry IEC 61511).
The approach of IEC 61508 is based on calculations which determine the probability of failure of the subsystems considering various factors such as the diagnostic coverage, safe failure fraction and the time range of diagnostic tests. The calculations are based on the probability of failure of individual components which, according to the hardware architecture of the subsystem, are linked with the usual rules of statistical calculation. The overall probability of failure of a system or of a safety function, realized with more subsystems, are calculated with the same criteria introducing, if applicable, considerations concerning the susceptibility of the subsystems to the failure modes for common cause.