Re: EMC and lead screw compensation

Wally replys:

Thanks for the reply Ray. 3 more questions.

1st do you or anyone else know what a reasonable measerment step
would be for the leadscrew compensation file. The easy awnser is the
smaller the step the better. But i have a feeling that at a certain
point you get diminishing returns.

2nd, is it ok to have different step sizes in the file. Example, you
measure every inch of the leadscrew and find a spot were it has
greater error than the rest of the screw. Can you enter in
measerments closer together in this region of the screw.


Ray wrote:

>
> Wally
>
> I haven't used lead screw compensation but it is there. It is done

by a

> lookup of a separate file it one exists for each axis. If you

write a

> comp file and put it in the correct place, it will be read. The

entry

> concerning it in the release notes says
>
> -----release notes-----
> 7. Added bidirectional lead screw compensation. Files of

compensation

> points look like this (these sample comp values are exaggerated):
>
> 0.000000 0.000000 -0.001279
> 0.100000 0.098742 0.051632
> 0.200000 0.171529 0.194216
> 0.300000 0.292485 0.291030
> 0.400000 0.439511 0.367981
> 0.500000 0.451323 0.493962
> 0.600000 0.618011 0.618044
> 0.700000 0.669925 0.735979
> 0.800000 0.798637 0.787879
> 0.900000 0.889286 0.927685
> 1.000000 1.007024 0.959853
> ...
>

Reference for 3rd question:

> where the first column is the commanded axis position, the second
> column is the measured position (like with a laser) in the forward
> direction, and the last column is the measured position in the

reverse

> direction.

3rd question, isn't forward and reverse direction relative. How can
we be sure we are putting the measured numbers in the correct
direction column.

>
>
> It looks to me like it would not only take care of rolled screw

error but

> might take care of some variable slop (backlash) as well.
>
> Ray
>
>