How do you perform end-to-end SIL loop testing?

End-to-end SIL loop testing: prepare written procedure with acceptance criteria, notify operations and obtain permit, bypass or inhibit trip output to prevent process upset, apply test signal at sensor (physical stimulus or simulated input), verify logic solver receives correct value and evaluates trip condition, verify final element responds correctly (valve position, motor stop), measure response time against requirements, document as-found condition, perform any required adjustments, document as-left condition, remove bypass and verify normal operation. Testing must achieve credited proof test coverage. Compare actual trip setpoint to design. Document deviations and corrective actions. Timing critical - ensure total response time meets SRS requirements.