APM
All alarm codes
ALARM 20

NMI Emergency Stop (spindle start)

Spindle VFD is drawing more current at start than the drive can supply — manifests as Alarm 20 'NMI Emergency Stop' as soon as the spindle is commanded on (a...

Controls
T-Plus
Machine series
Quick Turn

Causes

  1. Spindle VFD is drawing more current at start than the drive can supply — manifests as Alarm 20 'NMI Emergency Stop' as soon as the spindle is commanded on (axes still jog fine, tool changes work).

    • Philabusterforum
      Go to diagnostic screen before trying to clear the alarm. You should have more than one alarm showing. Just guessing but it sounds like the spindle VFD is drawing more current vs what you can provide.

How to clear it

  1. 1

    Slow the spindle acceleration on the FR-SE drive by changing settings on the #5 DIP switch on the drive card (reduces inrush current at start).

    • Philabusterforum
      You can slow down the spindle acceleration 'parameters' (which will reduce the AMP draw when spindle starts) by changing some of the settings on the #5 DIP switch located on the FR-SE drive.
  2. 2

    Before clearing the alarm, go to the diagnostic screen — there will usually be more than one alarm posted, and the secondary alarms tell you which subsystem actually faulted.

    • Philabusterforum
      Go to diagnostic screen before trying to clear the alarm. You should have more than one alarm showing.

Confidence: medium · Single thread but Philabuster (Diamond member, frequent Mazak responder) gives a specific drive-level fix (DIP #5 on FR-SE).

First sourced: 5/21/2026