Z LEVEL COMPENSATION
Z level compensation is a bed levelling/distortion correction function typically used in 3D printing or engraving. It uses a HAL user space component which utilizes the external offsets feature of LinuxCNC. The loadusr command in the handler_postgui file specifies an interpolation type, which must be one of nearest, linear or cubic. If none is specified or if an invalid word is specified, the default is assumed to be cubic.
When Z LEVEL COMP is enabled, the compensation component reads a probe data file, which must be called probe_points.txt. The file can be modified or updated at any time while compensation is disabled. When next enabled, the file will be reread and the compensation map is recalculated.
The probe data file is generated by a probing program which itself is generated by an external python program called gcode_ripper.py, which should be located in the configuration directory.
The necessary HAL connections are as follows:
net xpos-cmd compensate.x-pos <= axis.x.pos-cmd
net ypos-cmd compensate.x-pos <= axis.y.pos-cmd
net zpos-cmd compensate.x-pos <= halui.axis.z.pos-relative
net compensate-on compensate.enable-in <= qtdragon.comp-on
net eoffset-clr2 compensate.clear => or2_1.in1
net comp-count compensate.counts => qtdragon.comp-count
net map-ready compensate.map-ready => qtdragon.map-ready
setp compensate.fade-height 0.0
setp axis.z.eoffset-enable True
Workflow
- - navigate to config folder, set filter to Python Script, load gcode_ripper.py
- - set origin to match the origin of the gcode file to be probed
- - under G-Code Operations, check Auto Probe
- - File -> Open G-Code File
- - if necessary, make adjustments and press Recalculate
- - press Save G-Code File - Probe Only
- - save the generated file to the nc_files folder
- - exit gcode_ripper
There should now be a file in the nc_files folder called {something}-probe-only.ngc. Set the file filter to G-Code Files, navigate to the nc_files directory and load this file.
Without changing the offsets, run this program. Make sure the probe tool is installed. When complete, there will be a file in the config directory called probe_points.txt