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Okuma OSP Controller
Servo/Axis · Intermediate
Okuma OSP Alarm D 4688 - MCS Rotary encoder 3 error
The MCS received illegal data from rotary encoder 3 (HEIDENHAIN) on the axis shown in the object field. The encoder communicates but the position data is invalid, so the axis feedback cannot be trusted.
4688
Okuma OSP Alarm D 4688 - MCS Rotary encoder 3 error
MCS Rotary encoder 3 error
The MCS received illegal data from rotary encoder 3 (HEIDENHAIN) on the axis shown in the object field. The encoder communicates but the position data is invalid, so the axis feedback cannot be trusted.
Common Causes
- Defective HEIDENHAIN rotary encoder 3 sending corrupt data
- Damaged encoder cable or poor shielding letting noise corrupt the data
- Loose connector at the encoder or MCS end
Troubleshooting Steps
- 1Identify the axis from the object field, then lock out power before handling encoder connectors.
- 2Reseat the rotary encoder 3 (HEIDENHAIN) connector and inspect the cable run for crushing, coolant soak, or chafing.
- 3Check that the encoder cable shield is properly grounded at the drive end, since noise on a HEIDENHAIN signal line causes this kind of illegal data error.
- 4Power up and jog the axis slowly while watching for the alarm to return.
- 5If the illegal data persists with verified cabling and grounding, the corrective action is to change rotary encoder 3 (HEIDENHAIN) per the manual.
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