PLC / Digital I/O, Sensors & Actuators
Separate a PLC output command from actuator confirmation
A TRUE command can coexist with no motion because the output stage, field supply, drive enable or mechanical system is unavailable.
Environment and inputs: Industrial PLC / automation guidance · Verify the exact controller, module, firmware, engineering tool and machine documentation. Linked vendor examples apply to their stated products and library versions; observation, state changes and physical work require distinct authorization.
Observe and record
Observe the commanded state, available module diagnostics, independent feedback and machine permissive indications without operating outputs experimentally.
Interpret the evidence
The software command is one point in a chain, not proof of physical action. Feedback can itself be faulty or delayed.
Resolve and verify
Trace the approved command-to-feedback path and assign the demonstrated fault to the controls, electrical or mechanical owner. Verify the complete sequence after repair.
Machine and data safeguards
Do not force the actuator or bypass its permissives merely to prove the PLC output is present.