FluidNC Alarm 1
FluidNCAlarmPosition is lost: home again
A limit switch was hit while the machine was moving, so the controller stopped dead.
Position is lost: home again. FluidNC's message is just the alarm's name; GRBL's alarm 1 (the same alarm) says position is likely lost. (Hamrun's reading)
What to do
- Look at which axis is sitting on its switch, and why: a job too big for the bed, or a work zero set too close to the edge.
- Reset the controller, then unlock ($X) and jog the machine off the switch.
- Home the machine, then set your work zero again before restarting the job.
- If the switch triggers when nothing touches it, check its cable for a pinch, loose plug or a cable chain pressing on it.
What users reported CLAIMED · forum and issue reports, not official
- Repeated Alarm 3 and Error 9 mid-cut on a 3018 Pro. First blamed on electrical noise; the real cause was the cable chain nudging the Z limit switch. (one owner's report) r/hobbycnc thread, Jul 2026
Official FluidNC message: “Hard Limit” source
Got a different message?
Paste it into the decoder. Hamrun's editor checks your G-code before you run it, so a toolpath that leaves the machine's travel or a missing feed rate is caught before the machine stops.
Related codes
- GRBL 1.1 Alarm 1: A limit switch was hit while the machine was moving, so the controller stopped dead.
- grblHAL Alarm 1: A limit switch was hit while the machine was moving, so the controller stopped dead.
Official text copied from the FluidNC source on 2026-11-01. Steps and the position answer are Hamrun's reading unless marked “firmware says”. User reports are labelled CLAIMED.