X-axis doesn’t back up from limit switch when homing

It waits for the second axis to hit on the seek stage before it does the final locate move and pull off usually.

 

Test switches on the Troubleshooting tab, not working or wired to wrong axis port perhaps?

 

@Alex Chambers you really should get a Grbl board to play with (; - individual axis homing is not a default option in Grbl - you have to recompile it to enable it. So unlikely to help this user as a quick test.

Sorry about the duplication, but I don't keep tabs there - Facebook is not an official support platform, it's meant for people to show off cool stuff. Direct support questions to the forum or support.openbuilds.com rather than entertaining it there please

Regardless, I often prefer checking getting answers to questions myself (sorry to the OP if has to answer again), as I may notice a clue of some other sorts in the replies.

As an example, the hidden clues sometimes (or at least, the fact that reading this makes me think of a follow up question):

@David Kater: The default Grbl homing cycle moves X and Y at the same time. You mention "Moves onto the Y axis" - does yours move X only first? Then after hitting the switch once, only then does it start moving Y? If so, are you running a custom firmware image from somewhere? Or is that just worded incorrectly and X and Y does move at the same time.

Please do this check too - even if you already have - as crossing X and Y switch wiring can be a cause to the symptoms you described so far. Thus, don't just check if something changes when you press a switch, also check that its the correct axis that triggers.

Doesn't contain any Grbl Settings, just the machinetype $I value:


Make sure to connect to the BlackBox, before taking a backup

 

What was the onscreen error on the end of the video

Homing has two phases a fast search, and a slow locate.
XY moves at the same time till both hits the switches once. Only once both reached the switches (end of the search phase) should they move off (pull off first time) and reapproach at a slower speed to do the actual precise homing step. After that 2nd slower home it performs the final Pull Off.

Your video cuts off / swings out of frame right after the Y switch gets triggered at the end of the first phase. Assuming the 2nd phase didn't kickoff because the error on screen was telling you why not

 

we need those GRBL settings (-: Alarm 8 means it failed to clear the switch during pulloff. It did not move at all, which may indicate a problem in the homing speed settings, or a problem in the X axis max speed and acceleration settings

 

Still blank. Open the file before you post.

 

Yes, much better

Code:

$23=1  ;  Homing direction invert, mask

This is expecting the X switch on axis minimum, Y and Z at axis maximums (IE machine moves to Z=up, X=Left, and Y=Back)
Is this how you have it set up?
Jogging directions:
Z+ moves bit up and away from the workpiece
Y+ moves the bit back and away from the front of the machine toward the back
Z+ moves the bit towards the right of the workpiece



Was the error 8 "Homing fail. Cycle failed to clear limit switch when pulling off. Try increasing pull-off setting or check wiring." from the video with these parameters? Currently

Code:

$27=10.000  ;  Homing switch pull-off distance, millimeters

Try a higher number if Error 8 is still present with it set to 10mm, try 15mm for example

By the time you get to 20mm with it not clearing the switch, it means a switch is "stuck on" either because its wired to the wrong axis (it moves X away but the Y axis is still pressing on the X switch which is accidentally mounted by the Y carriage by mistake) or a proper faulty switch / short circuit in wiring (will show triggered on troubleshooting tab if you look before you jog the machine)

 

Confirm. Don't try random switching. Use the tools in CONTROL - making sure you understand which axis is which, that the right switch is installed on that axis, and plugged into the right port for that axis.

 

in your video it seems to me that the light on the Z limit comes on when the X gets hit. can we have some better pictures of those switch mountings and how they interact when at home?

 

Include more pics, Y, Z some of the wiring and connectors wouldn't hurt either

 

Right after Error 8 comes up and you close it, switch to the Troubleshooting tab and screenshot please. No jogging nothing. In this state, any switches lit (physically or in the Troubleshooting tab or both)

 

Check the grubscrews on the shaft coupler between the X motor and the X leadscrew. Perhaps its slipping during the direction change

 

Also please double check this. If X and Y motors are swopped, it might also be that it tries to move off the X switch, but Y moved instead thus alarming right after the Y moved.