Fanuc alarm 423: DSP DETECT ERROR
30i/31i/32i system alarm · Fanuc 30i/31i/32i-B
What it means
The DSP on the servo control path reported an error condition to the CNC. One documented cause is excessive FSSB optical cable length degrading the high-speed link timing; otherwise the servo card or related circuitry is suspect. Verify FSSB fibre lengths against specification before replacing boards.
Likely causes
- FSSB optical fibre cable run exceeding specified length
- Servo card / additional axis board fault
- Optical link degradation from dirty or kinked fibre
Need the part urgently?
Send us alarm 423 with your machine details — typical RFQ turnaround is 24–48h.