What causes fault code E031 (Encoder Feedback Loss)?

Encoder cable disconnected at motor or drive end â€” connector not fully seated. Encoder cable damaged â€” pinched, cut, or flex fatigue from repeated motion. Encoder power supply failed â€” 5V or 24V supply to encoder not present. Encoder itself failed â€” internal electronics or disc damaged. Electrical noise from nearby VFD cables coupling into encoder signal wires

How do I fix fault code E031?

Check encoder cable connections at both motor and drive â€” reseat connectors firmly. Measure encoder supply voltage at the motor connector â€” should be 5V or 24V depending on type. Inspect encoder cable along its entire run for damage, pinch points, or tight bend radius. If cable has been repeatedly flexed, replace with high-flex rated encoder cable. Swap encoder with known-good unit if cable and power check out. Verify encoder cable is routed at least 6 inches away from VFD output power cables

Encoder Feedback Loss

E031

Servo or motor drive has lost encoder feedback signal. Axis position is unknown and motion has stopped.

high general packaging palletizer asrs piler conveyor

encoder feedback servo motor cable position

Probable Causes (ranked)

Encoder cable disconnected at motor or drive end â€” connector not fully seated
Encoder cable damaged â€” pinched, cut, or flex fatigue from repeated motion
Encoder power supply failed â€” 5V or 24V supply to encoder not present
Encoder itself failed â€” internal electronics or disc damaged
Electrical noise from nearby VFD cables coupling into encoder signal wires

Fix Steps

1 Check encoder cable connections at both motor and drive â€” reseat connectors firmly
2 Measure encoder supply voltage at the motor connector â€” should be 5V or 24V depending on type
3 Inspect encoder cable along its entire run for damage, pinch points, or tight bend radius
4 If cable has been repeatedly flexed, replace with high-flex rated encoder cable
5 Swap encoder with known-good unit if cable and power check out
6 Verify encoder cable is routed at least 6 inches away from VFD output power cables

Field Trick

With the drive disabled, slowly rotate the motor shaft by hand while monitoring the encoder count on the drive display. If the count does not change smoothly, the encoder or cable is faulty.

Suggested Replacement Parts

Parts matched to fault category: Encoder

Omron E6B2-CWZ6C Rotary Encoder P/N: E6B2-CWZ6C-1024P/R Incremental, 1024 PPR, 5-24VDC, NPN open collector

AutomationDirect $85.00 Amazon $75.00 Digikey $95.00

Autonics E40S8-1024-3-T-24 Encoder P/N: E40S8-1024-3-T-24 40mm body, 1024 PPR, totem pole output, 8mm shaft

AutomationDirect $65.00 Amazon $58.00

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

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