Re: stepper backslash trouble...

[Ray <rehenry-at-up.net>]

On Sun, 06 Aug 2000, Rafael wrote:
> Hello emc-users,
> 
> I am using emc (rev. 06/07/00, rtlinux 2.2 with kernel 2.2.14) with
> stepper motors. When having backslash correction, the steppers perform
> it well in + direction, but in the - one emc claims an "axis following
> error" and goes to "estop reset". Am I missing something or is this a
> bug?

Hello Rafael

I am not able to reproduce your backlash problem on my controller here
but I can think of two possibilities.  There may be much better advice
from others on the list.

1 - There is a problem with steppermod.o in the release that you are
using.  It resets the values of several of the ini file axis variables
when you exit EMC or when an axis error occurs.   

Possible Solutions -
- Use freqmod.  It does not have this problem.  
- Recompile using the latest emcstepmot.c from sourceforge.

2 - Your ini file definitions of error, ferror, and min ferror may be wrong
for the amount of backlash you have asked for.  

While I couldn't reproduce the problem here, and don't normally use
backlash compensation, I was able to cause an axis error with large
backlash values (0.05 to 0.10) when I tried to home an axis.

If you could describe your setup in more detail or send a copy of your ini
file to me off list I'd be happy to try it here.

Ray
U.P. Michigan USA