Proximity Sensor Fault — No Target Detected

Proximity sensor expected to detect a target is not triggering. Equipment has stopped waiting for confirmation signal.

Probable Causes (ranked)

• Sensor face contaminated — dust, grease, metal shavings blocking detection
• Target moved out of sensing range — mechanical drift or bracket loosened
• Sensor cable damaged or connector loose — intermittent or no signal
• Sensor failed internally — no output regardless of target presence
• Wrong sensor type installed — inductive sensor for non-metal target or vice versa

Fix Steps

1. 1 Clean sensor face with non-abrasive cloth — remove dust, grease, metal particles
2. 2 Verify sensing gap — adjust bracket to bring target within rated sensing distance
3. 3 Check cable from sensor to input module — wiggle test while monitoring input LED
4. 4 Substitute with known-good sensor of same type to confirm failure
5. 5 Verify sensor type matches target material — inductive for metal, capacitive for non-metal
6. 6 Check PLC input status directly — sensor LED ON does not always mean clean PLC input

Suggested Replacement Parts

Parts matched to fault category: Proximity Sensor

Prices are estimates. Verify part numbers match your equipment before ordering.

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