Fanuc alarm SV0490: CNC SAFETY FUNCTION ERROR
safety/dual-check alarm · Fanuc 30i/31i/32i-B
What it means
The CNC detected an internal failure of its safety functions: non-execution of a safety routine, mismatch between CNC results and monitor/spindle cross-check results, a CNC RAM test error, CPU test error, or the power-up test never ran. Because the primary safety processor is untrustworthy, immediate stop is forced and Fanuc prescribes replacing the CPU card.
Likely causes
- Main CPU card hardware failure
- Cross-check mismatch from failing safety-monitor hardware
- Boot-time self-test interrupted or failing repeatedly
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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CPU card / main board
board · Common cause
Need the part urgently?
Send us alarm SV0490 with your machine details — typical RFQ turnaround is 24–48h.