1688

Common Causes

• Failed Rotary encoder 3 (HEIDENHAIN) producing illegal data internally
• Damaged or contaminated encoder scale/readhead causing corrupt signal output
• Loose, pinched, or oil-soaked encoder cable or connector between the encoder and the MCS drive
• Electrical noise on the encoder feedback line from poor shielding or grounding

Troubleshooting Steps

1. 1Note the axis shown in the [Object] field so you know which machine axis uses Rotary encoder 3.
2. 2Power down and lock out the machine, then inspect the encoder cable and connectors on Rotary encoder 3 for looseness, bent pins, oil ingress, or chafing along the cable run; reseat and secure them.
3. 3Check the encoder mounting and readhead area for coolant, chips, or contamination that could corrupt the HEIDENHAIN signal; clean carefully if accessible.
4. 4Verify the encoder cable shield is properly grounded and routed away from motor power cables to rule out noise-induced illegal data.
5. 5If the alarm persists after cable and contamination checks, replace Rotary encoder 3 (HEIDENHAIN) as directed by the manual, then verify feedback and axis operation.
6. 6If the alarm returns with a new encoder installed, record the alarm number, object axis, and conditions and contact Okuma service.