There are 1oo1, 1oo2, 2oo2, 2oo3 etc voting logic in the safety instrumented system architecture. The voting logic architecture usually used in the field instrument and or final control elements to reach certain Safety Integrity
Intrinsic safety (IS) is a low-energy signalling technique that prevents explosions from occurring by ensuring that the energy transferred to a hazardous area is well below the energy required to initiate
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.