Fanuc alarm SP0755: SAFETY FUNCTION ERROR
spindle alarm (safety monitoring) · Fanuc 0i-D
What it means
The CNC CPU detected that the safety function was not executed for the designated spindle within the required monitoring interval. This belongs to the Dual Check Safety environment, where an independent monitor must periodically verify spindle speed supervision. A failure means the safety monitoring chain itself is unreliable, so the CNC stops the spindle.
Likely causes
- Safety-related parameter mismatch between the dual CPUs
- Defective or unseated safety option hardware
- Incorrect Dual Check Safety setup after board or software change
Triage note: Requires Fanuc-qualified revalidation of the safety system after correction.
Need the part urgently?
Send us alarm SP0755 with your machine details — typical RFQ turnaround is 24–48h.