exida explains Blog

Entries tagged with: Hardware Fault Tolerance

Back to the Basics 18 – Route 1H

Back to the 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…

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The Architectural Constraint Blind Side
  • by Denise Chastain Knight, P.E., CFSE, CCPSC
  • Thursday, August 27, 2015
  • Certification

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)…

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