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…
Safe Failure Fraction (SFF) is defined as the ratio of the average rate of safe failures plus dangerous detected failures of the subsystem to the total average failure rate of the subsystem. It is defined for a single channel (no redundancy, 1oo1).
It is a measurement of the likelihood of…
The idea that diagnostics are useless contradicts everything I’ve ever learned and taught about diagnostics.
Diagnostics help identify problems. Diagnostics can turn a fault that is unrevealed during normal operation into a detected fault, which allows me to take action. That action could be an automatic transition to the…
Protection systems have been around for a long time, going back to having a canary in the mine, and throughout the Industrial Revolution; so they are not a new thing. Various stakeholders were involved in business enterprises: owners, suppliers, consumers, community members, and workers. Usually the business owners held…