Last edit: 03/03/2023
The Standard considers an interlocking device, with or without locking, a SRP/CS (safety-related parts of control systems) of a machine or a subsystem of a safety-related electrical control system (SRECS) with the purpose of preventing dangerous situations.
As such, interlock requires precise levels of performance (PL) or safety (SIL) with the respective periodic operational tests and CCF (Common Cause Failures) reduction methods.
The locking release functions must also comply with the PL or SIL.
The standard, then, deals with the logical connection methods of interlocks.
Finally, it is reminded to consider the electrical and environmental conditions in which the device is placed.