3135

Common Causes

• Failed DD encoder or DD encoder slave sensor on the reported axis
• Damaged encoder link cable or loose/corroded connector
• Faulty inverter unit control board
• Electrical noise or poor shield grounding corrupting the link (CRC/parity/format errors)

Troubleshooting Steps

1. 1Read the code number shown with the alarm: code YY=00 = Error detected at the DD encoder; code YY=01 = Error detected at the DD encoder slave sensor; code ZZZZ bit13 = Communication error with the DD encoder slave sensor; code ZZZZ bit12 = Communication error with the DD encoder; code ZZZZ bit11 = MT buffer error; code ZZZZ bit10 = Transmission loop error in AT mode; code ZZZZ bit9 = Data over error in the interface receiving section; code ZZZZ bit6 = Modulation code error
2. 2Note the axis in [Object] and the code: YY=00 points at the DD encoder, YY=01 at the DD encoder slave sensor; read the ZZZZ bits for the fault type (bit0 time-out, bit1 parity, bit5 CRC, bit12/13 communication error with encoder/slave sensor).
3. 3Lock out power and let the drive discharge before touching drive cabinet wiring; then inspect and reseat the encoder link connectors at the encoder and at the inverter unit for the reported axis.
4. 4Check the encoder link cable along its run for pinching, chafing, coolant ingress or sharp bends, and confirm shield/ground connections are intact; swap with a known-good cable if available.
5. 5If time-out/CRC/parity bits dominate and cabling is good, suspect the DD encoder (or slave sensor per YY) itself; substitute or have it tested.
6. 6Only after cable and encoder are eliminated, suspect the inverter unit control board; if the alarm persists record the full code and object and contact Okuma service.