FANUC Series 0i-F / 0i-F Plus alarm SV0411: EXCESS ERROR (MOVING)
SV0411 (EXCESS ERROR (MOVING)) on a FANUC 0i-F means the positional deviation of an axis while it was moving became larger than the limit in parameter 1828. The motor could not keep up with the commanded motion, so the control stopped it.
Diagnose this with AI
Try Free CNC Alarm Diagnostic Upload a keypad photo, the fault history or a parameter export from your FANUC Series 0i-F / 0i-F Plus. InduQT compares the evidence and suggests the next useful checks.
When it happens
- Rapid traverse (highest position error)
- Heavy cutting
- Jog or handwheel at the start of a move
- Reference return
Likely causes and checks
1Mechanical binding or a crash
- Points to it
- One axis only; alarm at the same position each time, or after a collision; jogging slowly is rough or noisy.
- Check
- With the axis isolated and locked out, check that the ballscrew, coupling and ways move freely and that way covers are not jammed with chips.
2Motor brake not releasing
- Points to it
- Vertical or braked axis; alarm right at the start of the first move after servo-on.
- Check
- Check that the brake releases when servo is enabled (brake supply and wiring per the machine builder’s diagram).
3Power or feedback cable fault
- Points to it
- Intermittent, sometimes only at certain axis positions where the cable flexes; may alternate with Pulsecoder alarms (SV0368, SV0446).
- Check
- Inspect and test the motor power and Pulsecoder cables; insulation-test the power cable and motor with them disconnected from the amplifier.
4Load or acceleration beyond the motor’s capability
- Points to it
- Only in heavy cuts or fast rapids; no fault found with the mechanics.
- Check
- Compare DGN 300 during the move with the 1828 setting; review feedrate, acceleration and cutting conditions.
5Parameter mismatch
- Points to it
- Alarm started after a parameter load, motor change or change of rapid rate or loop gain.
- Check
- Compare 1828, 1825 and the rapid rate with the builder’s backup; FANUC’s guideline sets 1828 from the rapid rate and servo loop gain with a margin of about 1.2.
Telling it apart
- SV0410 is the standstill version (parameter 1829).
- If SV0401 or an amplifier alarm comes with SV0411, the amplifier stopped driving and the excess error is a consequence; fix the amplifier alarm first.
- Alarm at the start of the first move points to brake or binding; alarm only at high speed points to load, acceleration or parameters; alarm at one position points to mechanics or a cable flexing.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| 1828 | Positioning deviation limit in movement | Limit for SV0411. FANUC’s setting guideline is the rapid-traverse position error (rapid rate ÷ (60 × servo loop gain) ÷ detection unit) with a margin of about 1.2. |
| DGN 300 (diagnosis) | Position error of each axis | Live position error in detection units. FANUC gives position error = feedrate [mm/min] × 100 / (60 × servo loop gain) × 1/detection unit, with servo loop gain from parameter 1825 in 0.01 s⁻¹. |
| 1825 | Servo loop gain for each axis | In 0.01 s⁻¹; FANUC lists 3000 as the usual value. Sets how much position error a given feedrate produces. |
Evidence to collect
- Axis, mode (rapid, cutting, jog) and position at the alarm
- DGN 300 during a slow and a fast move
- Parameters 1828, 1825 and rapid rate vs the builder’s backup
- Any recent crash, motor or cable work
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