What is a SIF?
SIF stands for Safety Instrumented Function. A SIF is designed to prevent or mitigate a hazardous event by taking a process to a tolerable risk level. A SIF is composed of a combination of logic solver(s), sensor(s), and final element(s).
A SIF has an assigned SIL level depending on the amount of risk that needs to be reduced. One or more SIFs comprise a SIS.