Process Override Switch shall be provided to override unhealthy field inputs in order to facilitate start-up, which shall automatically be released upon normalisation of the field input or preset time,
Maintenance Override Switch (MOS) shall be provided to override all field inputs designated to trip the facility in order to facilitate maintenance of field devices without interrupting the plant operation.
Perhaps the simplest form of sensor providing process information for a safety instrumented function is a process switch. Examples of process switches include temperature switches, pressure switches, level switches, and
A Safety Instrumented Function, or SIF, is one or more components designed to execute a specific safety-related task in the event of a specific dangerous condition. The over-temperature shutdown switch