Frequently Asked Question
We have a pressure transmitter with an SFF> 90% that we use in a SIL 2 with an HFT of 0 (see table 2 and 3 IEC61508-2). Then a Intrinsic Safety Isolated Barrier is also included in this loop (P&F). When we enter these 2 devices into exSILentia, the SFF de
Last Updated 5 years ago
Per IEC 61508, the SFF is determined per element or sub-system. exida published a white paper on this, see http://www.exida.com/Resources/Whitepapers/Position-Paper-on-IEC-61508. A SIL 2 capable transmitter will not automatically meet SIL 2 requirements, the overall SIF will determine this. In your case, you could opt to change the architectural constraints to IEC 61511:2016 which allows single use SIL 2 in low demand applications, regardless of SFF.