Fanuc alarm SV0494: n AXIS:SAFETY SPEED EXCEEDED (CNC)
safety/dual-check alarm · Fanuc 30i/31i/32i-B
What it means
While the safety function was active (door open / guard requested), the speed of feed axis n rose above the safety speed set in parameter No.1942 or Nos.13821-13824 as judged by the CNC channel. Safe-speed monitoring is the core DCS protection allowing setup work with doors open; exceeding the limit stops the axis immediately. Confirm the selected safety speed level matches the selection signals and that the axis is not coasting/drifting.
Likely causes
- Axis moving faster than configured safe speed during setup operations
- Wrong safety speed level selected via SVA/SVB selection signals
- Vertical or unbalanced axis coasting due to brake/counterbalance issues
Triage note: Spindle equivalents are handled by SP0757-type alarms and amplifier-side indication 69.
Need the part urgently?
Send us alarm SV0494 with your machine details — typical RFQ turnaround is 24–48h.