PLC / Digital I/O, Sensors & Actuators
Check PNP and NPN compatibility before replacing a sensor
A replacement sensor can be electrically incompatible with the input interface even when its connector fits and supply label matches.
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
Compare the exact sensor output type and module input circuit in their matching datasheets and the approved machine drawing.
Interpret the evidence
Sourcing, sinking and configurable input behavior are device-specific. A product's marketing label alone cannot establish the correct common connection or threshold.
Resolve and verify
Have the qualified electrical owner select the approved compatible part and perform any wiring correction through the isolation procedure, then validate normal signal detection.
Machine and data safeguards
Do not improvise jumper wiring or apply an external voltage to test an unknown input circuit.