Fanuc alarm SV0420: SYNC TORQUE EXCESS
αi/βi Servo (SV0xxx) · Fanuc 0i-D
What it means
In feed-axis synchronous control, the torque difference between master and slave axes exceeded the threshold in parameter No. 2031; only the master axis raises this alarm. Growing divergence in torque means the two mechanically coupled axes are fighting each other — usually from unequal friction, backlash, or one side losing feedback accuracy. Compare torque loads on both axes during motion to find the offender.
Likely causes
- Unequal mechanical friction/guideway load between paired axes
- Backlash or coupling wear on one side
- Feedback discrepancy between master and slave detectors
- Threshold parameter No. 2031 set too tight
Need the part urgently?
Send us alarm SV0420 with your machine details — typical RFQ turnaround is 24–48h.