On Sunday 07 March 2021 06:58:01 Gene Heskett wrote:

> On Sunday 07 March 2021 06:43:45 Gene Heskett wrote:
> > Greetings folks;
> >
> > Experimenting with various ways to see if I can find out why the
> > initial homing is so slow and loaded with windup effects, effects
> > that do not seem to affect the stepper driven axises.
> >
> > It takes at least 5 seconds for it to get up to search speed, and
> > another 5 seconds to get back to a stop after the home switch has
> > been found, coasting 20-25 degrees getting stopped, then it goes
> > into latch speed and takes another minute to get back to the switch
> > edge.  And theres a random offset being applied to the home position
> > in the linuxcnc dro that does not exist
> >
> > The randomness gets obviously worse if I crank up the thread speeds,
> > and causes a zero drift in the dro readings for repeatedly issuing
> > the g0a5;g0a-15 while attempting to optimize the servo settings.
> >
> > This machine's install is your latest respin of buster. Download,
> > burn and installed in late december IIRC.
> >
> > And rtapi shows up in an htop output, something that isolcpus
> > normally hides from htop.  That got me snooping.
> >
> > And there is no mention of isolcpus in /boot/grub/grub.cfg!
> >
> > From uname -a:
> > 4.19.0-14-rt-amd64 #1 SMP PREEMPT RT Debian 4.19.171-2 (2021-01-30)
> > x86_64 GNU/Linux
> >
> > Note the date!
> >
> > So, whats the current status of the isolcpus boot parameter?
> >
> > Also latency-test will not run, can't find the threads, fast or
> > slow.
>
> And on repeat test, it does run, runs well. But the one remaining
> atom's latency is horrible, 50+ u-s on both threads, the other 2 i5
> dells are in the 4 u-s region.  I have another dell i5 to replace it
> as soon as some 60 degree weather arrives.
>
> > So someting is fubared IMO, but what?

And, I just found that deleting position.txt while lcnc is stopped, or 
editing it to be all 0.0000000000 does not affect the dro on a rerun, 
and while once its homed, I can touch off xyz to effectively zero, I 
cannot touch off A, it has no effect.

Thanks for any clues to quadruple check.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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