Fanuc 414 Servo Alarm Z Axis Detect Error -

If a high-current device (spindle drive, coolant pump) is dumping noise onto the ground line, the servo drive’s position detection circuit can misinterpret feedback. Fix: Check that motor feedback cable shield is grounded at only the control end, not both ends.

The Z-axis is unique because it must constantly fight gravity. Common root causes include: Diagnose a Fanuc High Current Alarm in 10-Steps fanuc 414 servo alarm z axis detect error

Inside the Fanuc servo amplifier: