What causes fault code 30002 (Proximity Sensor Fault â€” Stuck ON)?

Sensor shorted internally â€” output transistor failed closed. Wiring short between signal wire and +V supply. Metal debris accumulated on inductive sensor face. PLC input module channel failed high â€” reads ON regardless of sensor. Electrical noise from nearby VFD cables inducing false signal

How do I fix fault code 30002?

Disconnect sensor from wiring â€” if PLC input remains ON, it is a wiring or module issue. Clean sensor face, remove any metal debris or buildup. Check cable routing â€” separate sensor cables from VFD and motor power cables by 6 inches minimum. Swap sensor signal to adjacent PLC input channel to rule out module failure. Replace sensor if internal short confirmed â€” match part number exactly

Proximity Sensor Fault â€” Stuck ON

30002

Proximity sensor output is continuously active regardless of target presence. Causes false position confirmations.

medium general conveyor piler asrs packaging palletizer

proximity sensor stuck short noise

Probable Causes (ranked)

Sensor shorted internally â€” output transistor failed closed
Wiring short between signal wire and +V supply
Metal debris accumulated on inductive sensor face
PLC input module channel failed high â€” reads ON regardless of sensor
Electrical noise from nearby VFD cables inducing false signal

Fix Steps

1 Disconnect sensor from wiring â€” if PLC input remains ON, it is a wiring or module issue
2 Clean sensor face, remove any metal debris or buildup
3 Check cable routing â€” separate sensor cables from VFD and motor power cables by 6 inches minimum
4 Swap sensor signal to adjacent PLC input channel to rule out module failure
5 Replace sensor if internal short confirmed â€” match part number exactly

Suggested Replacement Parts

Parts matched to fault category: Proximity Sensor

Allen-Bradley 872C Inductive Prox Sensor 18mm P/N: 872C-D5NP18-D4 3-wire DC NPN, 18mm barrel, 5mm sensing range, shielded

AutomationDirect $42.00 Amazon $65.00 Grainger $78.00

IFM Efector IFS204 Inductive Sensor 12mm P/N: IFS204 12mm flush mount, 4mm range, M12 connector, PNP NO

AutomationDirect $38.00 Amazon $45.00 Digikey $52.00

Balluff BES 18mm Inductive Sensor P/N: BES M18MI-PSC80B-S04K 18mm barrel, 8mm range, PNP NO, M12 connector

AutomationDirect $48.00 McMaster-Carr $55.00 Amazon $50.00

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

Need a deeper diagnosis with photo analysis and AI-powered troubleshooting?

Run Full Diagnosis