Fanuc alarm SV0413: LSI OVERFLOW

What it means

The positional deviation counter inside the servo LSI overflowed its capacity. This happens when enormous deviation accumulates — for example an axis mechanically held back while being fed, or grossly wrong loop gain/pulse scaling parameters. Investigate why deviation grew so large rather than treating the LSI as failed; genuine LSI failure is rare.

Likely causes

• Axis blocked/clamped while feed commanded
• Grossly incorrect servo parameters (loop gain, flexible feed gear)
• Sustained stall from overload
• Rare: servo LSI hardware failure