NPN vs PNP Sensor Wiring Explained
Send your PLC input type and the target distance — we confirm NPN or PNP and the sensor size.
NPN or PNP — which proximity sensor do you need? This one-minute animation shows 3-wire DC sensor wiring (brown +V, blue 0 V, black output), how a PNP output sources and an NPN output sinks current, and how to match the sensor to the PLC input.
Chapters
Key points
- 3-wire DC sensor: brown = +V, blue = 0 V, black = output.
- PNP sources current: on detection the output switches to +24 V and current flows through the load to 0 V.
- NPN sinks current: on detection the output switches to 0 V; the load sits between +24 V and the output.
- Match the sensor to the PLC input: PNP for sinking inputs, NPN for sourcing inputs.
Transcript
NPN or PNP: which sensor do you need?
A 3-wire DC sensor has a brown wire for +V, a blue wire for 0 V, and a black wire for the output.
A PNP sensor sources current. When it detects the target, the output switches to +24 V, and current flows through the load to 0 V.
An NPN sensor sinks current. When it detects the target, the output switches to 0 V. The load sits between +24 V and the output.
So match the sensor to the PLC input: PNP for sinking inputs, NPN for sourcing inputs.
SEGMENsensor proximity sensors: NPN or PNP, NO or NC. Learn more at segmensensor.com.