- by Loren Stewart, CFSE
- Tuesday, December 10, 2019
- Functional Safety
Back to Basics 18 – Route 1H
Route 1H is one of two Architectural constraints options made available in the standards IEC 61508-2 and IEC 61511. Route 1H . Both Route 1H and Route 2H are limitations that impose the hardware selected to implement a safety-instrumented function, regardless of the performance calculated for a subsystem.
Route 1H is…
- by Denise Chastain Knight, P.E., CFSE, CCPSC
- Thursday, August 27, 2015
The Architectural Constraint Blind Side
I did my homework, purchased certified devices, and specified physical redundancy. I expected an uneventful SIL Verification but the assessor is telling me that I have functions failing Architectural Constraints in the sensor and final element groups. How can that be?
Low demand mode Safety Instrumented Function (SIF)…