AMNYTT # 6 2016 the safety logic solver is configured to detect Low failure and does not automatically trip on this failure, this failure has been classified as a dangerous detected( DD) failure;

• fail“ No Effect”: failure mode of a component that plays a part in implementing the safety function but that is neither a safe failure nor a dangerous failure. When calculating the SFF, this failure mode is not taken into account;

• fail“ Not part”: failure mode of a component which is not part of the safety function but part of the circuit diagram and is listed for completeness. When calculating the SFF this failure mode is not taken into account.

The 2 channels of the D5014D module could be used to increase the hardware fault tolerance, needed for a higher SIL of a certain Safety Function, as they are completely independent from each other, not containing common components. In fact, the analysis results for D5014S( single channel) are also valid for each channel of D5014D( double channel). This analysis is also valid for D5014D as Duplicator of 2 wires Transmitter Input Signal, but considering safety function is only applied to the channel configured as passive input. Failure rate data: taken from Siemens Standard SN29500

Sikkerhetsmanualen skal også gi en oppsummering av feilraten: Tabellen nedenfor forutsetter et resultat på T-proof-testen = 99 %. Dette vil ikke være praktisk uten råd og veiledning om hvordan testen skal utføres!