Fanuc alarm SP0756: AXIS NUMBER ABNORMALITY
spindle alarm (SP07xx) · Fanuc 0i-D
What it means
Under Dual Check Safety, the identification number of the monitored spindle axis as seen by the amplifier does not agree with the configuration the CNC expects. The safety architecture requires every monitored axis to be uniquely and consistently identified across both monitoring channels, so any divergence blocks operation. On machines with a second serial spindle this alarm is classically caused by the missing K76 jumper on the JA7A connector.
Likely causes
- K76 jumper not fitted on JA7A of the second spindle interface
- Amplifier replaced without updating its axis-number assignment
- Divergent configuration data between the two safety monitoring channels
Triage note: Check hardware jumpers and diagnostics before replacing any board.
Need the part urgently?
Send us alarm SP0756 with your machine details — typical RFQ turnaround is 24–48h.