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grbl / grbl

An open source, embedded, high performance g-code-parser and CNC milling controller written in optimized C that will run on a straight Arduino
https://github.com/gnea/grbl/wiki
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GRBL homing problem when using the homing cycle in G-code after G1/G0 commands #1874

Open Turner66 opened 7 months ago

Turner66 commented 7 months ago

Hello,

I'm encountering an issue with GRBL where homing commands within G-code aren't functioning as expected after movement commands. Specifically, I'm trying to initiate a homing cycle at specific points within my G-code sequence. For instance:

$H G1 X100 F1000 G1 Y0 $H G1 Z10 F100 G1 Y30

However, only the first homing command seems to work reliably. Once a homing command is issued after a G1/G0 movement command, subsequent homing commands do not function correctly.

Interestingly, this works with Marlin firmware.

Has anyone encountered a similar issue with GRBL, and if so, is there a workaround or solution available? Any insights or suggestions would be greatly appreciated.

Kind regards Tim

breiler commented 7 months ago

$H is not a gcode command and should not be included in a gcode program.

Are you really using $H on Marlin or are you using their interpretation/implementation of G28 (https://marlinfw.org/docs/gcode/G028.html)?

Read about G28 in GRBL here: https://github.com/grbl/grbl/wiki/Frequently-Asked-Questions#why-are-some-of-grbls-g-codes-a-little-different-as-on-some-other-cnc-machines and here https://www.linuxcnc.org/docs/2.5/html/gcode/gcode.html#sec:G28-G28_1.

As far as I know you can't do homing as a part of gcode program in GRBL, this must be done through the sender.

Turner66 commented 7 months ago

Thanks for the quick reply. yes, in the marlin example I used g28 instead of $H. In marlin, as you wrote, g28 is the command for the homing cycle. unfortunately this is not the case in Grbl. maybe there is the possibility to add a G command for homing (like in Marlin).