Richard J Kinch wrote: No, not sure of the concept there.
Refer:
linuxcnc.org/docs/devel/html/motion/external-offsets.html
And axis.L.eoffset-counts
linuxcnc.org/docs/devel/html/man/man9/motion.9.html
These are 2.9 docs but it also applies to 2.8
This is very cool and how we manage torch height control on plasma machines.
Think of eoffsets acting as a MPG so it has a scaled count
To play, you need apportion a percentage of your velocity and acceleration in your axis set up in your ini file (eg limiting your max values)
So you introduce a scaled count to the eoffset-count pin that represents your deviation from the actual true axis reading, Linuxcnc will offset the axis accordingly. There are some sims to illustrate this provided in 2.8 and 2.9
So for a simple example to see this in action on a live machine, imagine that you had a non-square axis. We actually did this for a user on the forum. Say we are out of square by 10 cm per metre (10%) along the Y axis in relation to X.
If you multiplied axis.Y.pos−cmd x 0.1 and your scaling factor and send that to the eoffset-count pin for Axis X, you should see the axis move diagonally as you jogged along that axis to compensate for your supposedly crooked axis..
So in your application, if you had reduced the error to a formula or a lookup table, you could easily adjust for the error independent of any Gcode. You may need to write a small component.
Think about how you could apply it. It will work.
EDIT, my maths might be a bit sloppy there but I'll leave you to think about it.
