Photoelectric Sensor Fault

Photoelectric sensor (through-beam, retro-reflective, or diffuse) not functioning correctly. Product detection unreliable.

Probable Causes (ranked)

• Lens dirty — dust, moisture, or product residue on emitter or receiver
• Reflector damaged or misaligned (retro-reflective type)
• Emitter or receiver beam angle shifted — mounting vibration
• Ambient light interference — sunlight or high-bay LED strobing
• Sensitivity set incorrectly — too high causes false triggers, too low misses product

Fix Steps

1. 1 Clean both emitter and receiver lenses with soft lint-free cloth
2. 2 For retro-reflective type: clean reflector, verify it is square to sensor beam
3. 3 Check mounting brackets — tighten all hardware, verify beam alignment
4. 4 If ambient light issue, add sensor hood or switch to modulated frequency type
5. 5 Adjust sensitivity using teach button or potentiometer — follow sensor manual
6. 6 Verify wiring: NPN vs PNP output must match PLC input type

Suggested Replacement Parts

Parts matched to fault category: Photoelectric Sensor

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

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