On Friday 19 September 2014 22:37:16 Jon Elson did opine
And Gene did reply:
> On 09/19/2014 04:22 PM, Gene Heskett wrote:
> > Hi have made a wee bit of progress with the spindle controls on the
> > lathe, but lower speed performance is still sorely lacking.
> > 
> > Current pid.s settings
> > Pgain 125
> > Igain .05
> > FF0   100
> > FF1    20
> > 
> > maxoutput is set 1% below the pwmgen scale to keep it from hitting
> > 100% duty cycle.
> 
> When you get into it a little further, you may have to give
> it as much at
> 5% headroom.  But, if you are now at a lower PWM frequency,
> then it
> needs less percentage, just to make sure it gets at least
> something like
> 1 us off time per cycle.
> 
> >    Since this is a parameter, I cannot put the gearchange
> > 
> > bewteen the pid and the pwmgen because the pwmgens scale and the
> > pid.maxoutput limits must be maintained.
> 
> Maybe you could put gearchange BEFORE pwmgen?

Sensibly, that would appear to be the ideal place to put it, but with the 
1% off cycle safety margin established by pid.s.maxoutput, I would lose 
the insurance of never driving it to 100% duty cycle. But a limit3 module 
after the gearchange could be used to re-establish that. Let the pid.s 
become unlimited and put the ceiling into the limit3.maxv.

I'll check that out tomorrow.

Thanks for making me think Jon.
 
> > I had to change  editors from gedit to geany because gedit was
> > snatching 10 to 15 character snippets of the file and inserting then
> > at several other places in the file, totally mucking with variable
> > names and such. At about 1 in 20 saves I'd guess.
> 
> NEVER seen anything like that.  I would run memtest86 and
> make sure
> the CPU and memory are functioning properly.

It has been run, for a day & a half, dead clean but not exactly recently.  
If geany ever does it, yup on the memtest86 session, instantly.  So far, 
geany has not had any such hiccups.

But I don't have to tell you what that faint thumping sound is. :)

Cheers Jon, 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)
Genes Web page <http://geneslinuxbox.net:6309/gene>
US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS

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