Re: High stepper rate troubles

[John Weismiller <johnweis-at-home.com>]

Hello,

I tried changing the PERIOD, but this did not help.  I tried both
increasing and decreasing the value.  I tried 0.000008, 0.000048 and even
0.00048.  I think that the default value should be okay, as the system is
a Celeron 433.

I also tried freqmod but all I could get is axis following errors.  I
changed the P to 60 and default and max accel. in the [TRAJ] section to
1.5 as recommended in one of the posts on this list.  It would slowly get
to about 0.0012 and then give the error.  I also noticed the mbuff
problems when using freqmod.o.

When using steppermod.o, everything works fine if I set the INPUT_SCALE
for each axis to 20000.  It's only when I change it to 40000 that it
causes the computer to crash.

I have been reading through the source code, and I noticed that the
period of the stepper motor task seems to linked to both the input scale
and the max velocity.  Is this correct?  I tried changing the
MAX_VELOCITY, but that did not help.  Can anybody tell if I am on the
right track?

Thanks,
John.

On Thu, 23 Nov 2000, Lawrence Glaister wrote:

> 
> you probably need to increase the PERIOD variable from 0.000016 to something
> like 0.000048, and I would try using freqmod instead of steppermod.o. ( I am
> running the latest cvs release on redhat 6.2 with 2.2.14 kernel patched with
> rtlinux_2_2a). I'm not sure if the older versions of emc
> have the freqmod.o module. The above period works with my P133. I can get
> away with 0.000032 but there is very jerky gui interaction at that rate.
> 0.000016 definitely locks me up when the motor controller module loads.