Proximity Sensor No Output – Troubleshooting

When proximity sensor does not switch: wiring, power, and target issues.

Symptom: Sensor does not detect target

1. 1

   Verify power supply

   Check 24V DC at sensor. Brown (+) and blue (-). Reversed polarity can damage sensor.

2. 2

   Target material

   Inductive sensors detect ferrous metals only. Use capacitive or photoelectric for non-metallic targets.

3. 3

   Sensing distance

   Target must be within rated sensing distance (Sn). Typically 0.8×Sn for reliable operation. Ferrous factor affects range.

4. 4

   Output wiring

   NPN: black to load, load to +24V. PNP: black to load, load to 0V. Ensure PLC input type matches.