[VinCh1]

Hi there, let's me breakdown some history detail. The machine was replaced its glass scale on the X-axis after the previous one was broken. The X-axis is driven by the linear motor. After making the new change, when we try to move the axis, the error 411, 475, 1071 always show up. These happen sometimes at the lowest feedrate and the axis is not able to move at higher feedrate.

What we've tried
- Check motor's wires (good)
- Move the axis manually (no obstacle - good)
- Try to adjust the gap between the linear motor and permanent magnet but no hope

The machine components
- FANUC LINEAR MOTOR LiS-B series
- Heidenhain glass scale

The diagnostic panel might have some noticed errors but I have no ideas. I'm new to this.
Param 0353 Servo DGN Data: X-axis value, compared to others, fluctuates even being idle
Param 0303 Servo Error is obviously high and getting many higher when axis moving.

Big Thanks in advance

[elephantcnc]

After replacing the Heidenhain linear encoder (glass scale) on the X-axis of your CNC machine, you're encountering FANUC servo alarms 411, 475, and 1071 (excessive following error during movement/standstill). Possible causes include:
Misaligned or unstable encoder signal (Key issue—check DGN 720-723 for signal fluctuations).
Incorrect linear motor air gap (Should be 0.3–0.5mm uniformly).
Insufficient servo tuning (Try increasing Param 2021 PGain).
Mechanical binding or electrical noise (Inspect cables and grounding).

Recommended steps:
Realign the encoder and verify signal stability.
Check the linear motor’s magnetic gap for consistency.
Adjust servo gains if needed.
If the issue persists under motion (but not manually), focus on feedback signal integrity or dynamic load problems.