The gantry stopped in its tracks, with a loud screaming noise - as though it had run into something, but there is nothing for it to hit. As evidenced by the fact that after clearing the alert, I can continue to jog the X-axis
A few things come to mind. My guess is that it has nothing to do with homing. The homing cycle isnt completing so that's why you're getting the 30mm reading on the DRO. @Peter Van Der Walt correct? Does it still happen if you G0 X0? I had a similar issue on my Y axis on one end of my machine. It was binding near the end of the axis when at full speed. Stopping before the bind and jogging in 10mm increments wasnt an issue since the machine wasnt getting up to full speed. I fixed the issue by adjusting my endplate. Other thing to check is loose motor connection or motor wire being stressed at that point.
Re the video: Around 40 seconds into the video: "but it doesn't update" - Note: During Homing Grbl does not send DRO (well, status updates) info: See gnea/grbl for more, pasting screenshot of relevant section below As Grbl isn't giving us a response, we can't show you anything while its homing At 0:58 "I'm expecting it to come back to X0" - well, maybe, but maybe not: 1) You home (that sets MACHINE COORDINATES) 2) You jog, or do something, or even nothing in between - could affect where this "zero" is you wanted to return to (but not the reason this time in the case of the video, see 7 below) 3) You SETZERO (sets the work coordinates, an offset from Machine Coordinates) 4) You are at Work X0, and make a manual move to X1290 in Work Coordinates 5) You HOME (which would have reset the machine coordinates) 6) At 1:04 you abort the home before it completes (Abort not only stops whats going on but also reboots grbl) 7) Because you aborted, it could not set Machine coordinates, so now you have no real reference to Machine coordinates and thus all other offsets are going to be nonsensical, as all offsets (work coordinates, etc) are just Offsets from Machine coordinates (which is now unknown because of the aborted homing cycle) So from what I could see in the video - Read the Grbl wiki - I know pages like the Interface page linked above seems irrelevant, but see, it does contain info on how/why things happen, so do read it - Don't abort the Homing cycle, without a completed homing cycle, any and everything you do thereafter is irrelevant and won't make sense - Do some additional reading on Machine/Work coordinate systems --------------------------------------------- Of course I'd recommend sorting out your mechanical portion first before moving on to advanced setups like Homing --------------------------------------------- I agree with @sharmstr on That would take you back to 'zero' - homing is something else... It sets Machine Coordinates 'zero' in parenthesis as it may or may not take you to the switch, it will actually take you to where you was when you clicked setzero. If you wanted to test the same as G0X0 with homing you would have to meticilously: - Home - Setzero exactly where it stopped after homing (sets the offset of zero as where it was after it homed) - Jog away from switches - Rehome Then it should be back to "zero" in work coordinates (returns to the saved offset above, within the accuracy of the switches of course) Or if you wanted to test it in Machine coordinates, use G53
