Fanuc alarm STATUS2:U: FSSB communication error COP10B (servo unit)
αi/βi SVPM · Fanuc αi/βi SVPM
What it means
STATUS2 'U' on the βi SVPM (or any βi SVM in the FSSB chain) means the amplifier is not receiving downstream FSSB optical communication on COP10B — the fault is at or near the amplifier closest to the CNC showing 'U'. During power-up 'U' blinks briefly then settles to '-'; that is normal.
Likely causes
- Damaged/unseated COP10B optical fiber on the affected unit
- Optical module failure in the affected amplifier
- CNC servo card failure (when first amplifier in chain shows U)
Triage note: Replace cables starting at the unit nearest the CNC that displays U.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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COP10B optical fiber cable
amplifier · Primary suspect
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A06B-6134-Hxxx / A06B-6230-Hxxx (affected SVPM)
amplifier · Check if others ruled out
Need the part urgently?
Send us alarm STATUS2:U with your machine details — typical RFQ turnaround is 24–48h.