Frequently Asked Question
I’ve copied the parameters from a supplier in SILver, but I don’t understand why the PFDavg value calculated in SILver (3.10E-02) is different to the value in the manufacture datasheet (8.76E-04) for Sensor TMT82 of Endress+Hause for 5 years? 1oo1, theref
Last Updated 5 years ago
The manufacturer most likely did not consider a 20 year Mission Time, but instead only 5 years. Also, they most likely did not consider the maintenance capability, MTTR, and Repair Time. You are looking at an extremely simplified and optimistic formula. If you want a more detailed formula to compare, you may want to consider:
http://www.exida.com/Books/safety-instrumented-system-design-techniques-and-design-verification
http://www.exida.com/Books/safety-instrumented-system-design-techniques-and-design-verification