Add G38.4 and G38.5

[michielbaird]

Requirements

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Description

Add support for G38.4 and G38.5

This adds the option to move away from the target and stop as soon as the Z-endstop stops being triggered. See: http://linuxcnc.org/docs/2.6/html/gcode/gcode.html#sec:G38-probe

• G38.2 and G38.3 move in a direction and stop as soon as the Z-endstop is triggered.
• This PR extends this functionality to stop was soon as the endstop is un-triggered.

Benefits

• I intend to use this function to add auto skew correction on the Prusa MK42 board
• This will be used to calibrate the position of the induction pads.

Related Issues

#6199

[thinkyhead]

Looks good. As soon as it passes it can be merged. I don't recommend trying to piggyback MK2 skew calibration onto G38, but you may be able to use the underlying probe changes via a separate G-code. I don't know what Prusa uses, but I suggest overloading M852.

[thinkyhead]

To get this rebased, squashed branch to your working copy:

git fetch origin
git checkout add-G38.4-and-G38.5
git reset --hard origin/add-G38.4-and-G38.5

[michielbaird]

Thank you very much, looking forward to seeing this get merged

[boelle]

i look forward to this also :-D

the only thing i'm not sure on is my probe offset, the nozzle can go to 0,0 when i ask it to and i can place the nozzle on the 250,210 corner diagional to 0,0 so i assume that my X and Y min numbers are correct

so far i have used bilinear and some carefull selected numbers to get it to hit the 9 prove points on the bed, but it has always seemed like the probe was not on dead center

how can i check that my offset is correct ? (just asking so i can prepare for when the next bit is added)

[michielbaird]

@thinkyhead I think this is a bug, this should be a 3

[thinkyhead]

Thanks! I usually double-check my late-night coding the next day, but I was about ready to just merge and forget!

[michielbaird]

how can i check that my offset is correct ? (just asking so i can prepare for when the next bit is added)

Part of the calibration is calibration is calculating this offset translation. My endstops on my clone are out of spec so I expect this to come up during my testing