Fanuc alarm SV0492: F-BUS TEST ERROR
safety/dual-check alarm · Fanuc 30i/31i/32i-B
What it means
The F-Bus test failed. The F-Bus carries the safety cross-check to the sub-CPU board or loader control board, so this test only runs on systems using those boards; a failure implicates the mother board or the option (sub-CPU/loader) board. Replace the implicated board pair as Fanuc advises.
Likely causes
- Sub-CPU board or loader control board failure
- Mother board F-Bus interface failure
- Board not fully seated
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
- Request a quote →
Sub-CPU board / loader control board
board · Check if others ruled out
- Request a quote →
Mother board
board · Check if others ruled out
Need the part urgently?
Send us alarm SV0492 with your machine details — typical RFQ turnaround is 24–48h.