Fanuc alarm SV0471: n AXIS:SPC SOFT DISCONNECT (MNT)
safety/dual-check alarm · Fanuc 30i/31i/32i-B
What it means
The monitor CPU detected a pulse coder (serial feedback) signal error on axis n while cross-checking against the CNC CPU channel. Both channels read the same encoder; a discrepancy or broken feedback trips this safety alarm and stops the axis immediately. Remedy per Fanuc is replacement of the pulse coder.
Likely causes
- Serial pulse coder failure
- Feedback cable damage or noise on the JF1 leg
- Loose connector at the amplifier or coder
Triage note: Counterpart alarm SV0453 is the same detection made by the CNC (control) side.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
- Request a quote →
alpha i pulse coder (per motor/model list)
unit · Common cause
Need the part urgently?
Send us alarm SV0471 with your machine details — typical RFQ turnaround is 24–48h.