Change the axis limit

The short answer is, yes, you can change axis limits through HAL connections as well as through GCODE but there are a few things you need to be aware of.

- Axis limits are exposed as hal pins only after the GUI has started up. So any hal connections would need to be made in the POSTGUI_HALFILE
linuxcnc.org/docs/html/gcode/overview.html#gcode:ini-hal-params
As stated in the documentation #<_ini[section]key> parameters are read_only so if you want to change the value from Gcode you have to use a custom Mcode that uses a script language (eg tcl or bash) to execute a 'halcmd'

- Changes to ini parameters during GCODE execution will only become effective AFTER a quebuster command (eg M66 E0 L0)

My usual solution to change ini parameters from GCode is this:

1. save this bash script as 'M123' to a folder named 'mcodes' in your machine config folder and mark as executable:

To make sure that the changes are actually used we call the above script from a GCODE subroutine.

2. Save the following code as 'm123_wrapper.ngc' and save to a folder in your [RS274NGC]
SUBROUTINE_PATH

To make linuxcnc aware of these mcodes add these lines to the [RS274NGC] section of your ini file
Note 'argspec=PQ' will enforce that the 'M423' command is followed by a 'P' word containing the code for which axis [X(1),Y(2)] and which limit [min (1), max(2)] should be changed and a 'Q' word containing the limit value.
example usage:will set 'ini.x.max_limit' to '401'


The parameter handling can be changed to your specific requirements in the 'case' part of the bash script above.

You are looking at 'ini.0.' values. Those correspond to the [JOINT_0] section in the ini file. If you want to see the [AXIS_X] values you would need to navigate to 'ini.x.' which should be lower down in the list on the left hand side of the screen shot.