homing order configuration option

[mhv-shared]

On my corexy, Y must be homed before X, otherwise it won't hit the stop.

Obviously I can use G28 Y G28 X G28 Z, but it would be nice if G28 or G28 XYZ would function safely as well, in case a misconfigured slicer was used.

It looks like this will be a simple change, if you agree it's worthwhile I'll open a PR.

[KevinOConnor]

I have no objection to supporting it. Is there a similar feature in Marlin? If you have code available, I'd like to see it.

Thanks,
-Kevin

[mhv-shared]

I think this is the relevant code in Marlin: MarlinFirmware/Marlin#1957

I opened a PR #27.

[KevinOConnor]

Thanks. That PR looks like it changes the default homing order, but doesn't prevent an invalid homing operation. If your printer doesn't home Y before X, does the head crash into the frame? I'd be more concerned about verifying that a crash wont happen then making the G28 more user friendly.

Also, I think some users have printer that can only home the Z with a bed probe, and thus they have to move their X and Y to a set coordinate before homing Z. I wonder if a similar mechanism could be used to support that setup.

-Kevin

[KevinOConnor]

I've created a new test branch ( work-homing-override-20180116 ) that will allow one to define a series of g-code commands to run in place of G28 commands found in the normal input stream. It's activated by a new [homing_override] config section - see config/example-extras.cfg on the new branch for details.

I'd like to get feedback on this code.

git fetch ; git checkout origin/work-homing-override-20180116 ; sudo service klipper restart

[KevinOConnor]

I've merged the work-probe-20170609 branch (which includes the work-homing-override-20180116 changes) into the master branch.

[StefanMeGit]

Sorry i still have a question about this...

How is to use this? I tried a lot combinations like:

[homing_override]
gcode: G28Y \nG28X

or

[homing_override]
gcode: G28Y G28X

But nothing gives me the Y before X homing. What did i wrong here?

[mmone]

Had the same issue. Put each GCODE command in a separate line. And for some reason a whitespace is needed in front of every new line.

Like that:

[homing_override]
gcode:
 G28 Y0
 G28 X0
 G28 Z0

[StefanMeGit]

ahhhh i tried this also, but without space in front. Thanks! I ll try it.

[Spartacus1066]

I did this in printer.cfg to lift the head 5mm then home as normal. If I have to cancel a print, I can quickly HOME the printer while nozzle is still hot and not bonding to my print. If you use the menu or send G28 via terminal.

#Sets immediate position to 0 on all axes, G91 relative pos, lift Z 5mm, G90 absolute pos, normal G28
[homing_override]
set_position_x: 0
set_position_y: 0
set_position_z: 0
gcode:
 G91
 G1 Z5
 G90
 G28