Fanuc alarm 114: FSSB DISCONNECTION (MAIN -> AMP1)
30i/31i/32i system alarm · Fanuc 30i/31i/32i-B
What it means
An alarm was detected on the FSSB optical servo bus line x, with loss of communication between the units given in parentheses (here the CNC servo card and the first amplifier; related messages cover AMPn->AMPm and SDU links). No FSSB communication can be performed between the stated units, so axis control stops. The message identifies exactly which two neighbours lost contact, which makes isolating the failed fibre segment or module straightforward.
Likely causes
- Disconnected, damaged or dirty FSSB optical fibre cable between the two units
- Servo amplifier, separate detector interface unit or FSSB I/O unit power-off or failure
- Servo card / additional axis board failure on the CNC side
Triage note: Variants 114-125 report the same fault for every possible neighbour pair (MAIN, AMPn, SDUn) and direction.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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FSSB optical fibre cable (per machine tool builder list)
cable · Common cause
Need the part urgently?
Send us alarm 114 with your machine details — typical RFQ turnaround is 24–48h.