Re: [CAD_CAM_EDM_DRO] Ball/Lead Screw mapping

Kim Lux wrote:

>Where/how does EMC do this ? I haven't seen it anywhere in the code or
>setup ?
>
>

Yup, another big hole in the documentation. I must admit I don't
know how to do it, as I don't have home switches on my machine
yet.

Well, I have been assured by Fred Proctor and I believe Matt Shaver
that they have tested the machine error compensation and it works
exactly as it should. Now that I look for this feature, i can't find a
shred of evidence for it, either. I was under the impression that you
entered the correction points as specific numbers in the variable
table file.

I did find a file in .../emc/src/emctask/alter.c that applies a phoney
compensation on each axes' scale, which does almost what machine
error comp does, only in a linear fashion, like a temperature correction
factor.

If you look at the end of file .../emc/src/emcmot/usrmotintf.c, you
will find the function :

int usrmotLoadComp(int axis, const char * file)

which handles reading in the table and setting up the axis to be
compensated. I guess you call that internal documentation. The
routine has error messages that explain what it wants, somewhat.
Obviously, this needs to be documented better and put into the
main docs on linuxcnc.org

Jon