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Probe causes Alarm and won't function as a probe


I’m trying to dip my toe into the world of z axis probing. I have a probe/switch connected up to the probe and ground connection on the GRBL AIO, but I’m having trouble with its operation. If I try to use G38.2 to 0 the z axis, when the probe/switch touches the bed UGS goes into Alarm 3 instead of a normal (from what I’ve read) probe response. I’ve also tried inverting $6 and using a normally closed switch (which to me confirmed that I had my wiring correct), but again once the probe hits the bed it goes into alarm state.

Does anyone have any experience with using a probe on the GRBL AIO or could offer some advice? Cheers. Chris.


Are you issuing a full G38, for example at a minimum G38.2 Z-100 F100?
Alarm 3 suggests a reset was issued during the probing cycle.
This could mean that your probe is connected to the abort pin and not the P pin? Please check that first.
Check that the probe pin does not restart the firmware or even show anything in the console output unless you are in a probing cycle