On Wednesday 22 September 2021 19:52:57 Leonardo Marsaglia wrote:

> > Not totally laid up, yet. But I'll be 87 very shortly, and the yard
> > work I was doing for about 3 hrs earlier will still be yelling at me
> > tomorrow. Getting old is not for the faint hearted, specially when
> > your ticker is running on a battery and already has rebuilt valves
> > just to keep it pumping at 30%. For me, thats good, and sure beats
> > the alternative.
>
> I hope I could be at least half active as your age as you are. Glad to
> know you're busy!
>
> Besides, he is not ready for me yet, I'm too much of a maverik. ;o)
>
> > Gabriel would send me down, I'd fix the stoker, install electricity
> > and airconditioning, start a brewery and open a bar...
>
> I started to get thirsty when you mentioned the brewery LOL.
>
> El mar, 21 sept 2021 a las 18:24, Gene Heskett
> (<[email protected]>)
>
> escribió:
> > On Tuesday 21 September 2021 16:53:44 Leonardo Marsaglia wrote:
> > > > There may be a miss-understanding of its purpose,or I'm useing
> > > > it off its purpose.
> > > >
> > > > I am feeding lincurve with the absolute z position as delivered
> > > > to the motion input from the stepgen. So it knows where on the
> > > > bed it is. That allowed me to setup a laser, useing a knife edge
> > > > in the tool holder,and measure the bed wear error, program that
> > > > into the lincurve module, who output is then applied to the
> > > > offset to correct this error in the x axis as it moves in the z
> > > > plain. So I can turn within a thou over 3 feet of z motion that
> > > > has 13 thou of bed wear right in front of the chuck.
> > > >
> > > > Thats how I use it, but the offset module doesn't care where
> > > > this offset signal comes from, so don't be afraid to let your
> > > > imagination out to play with only a common sense chaperon. ;o)
> > >
> > > Hello Gene!
> > >
> > > Well, from what I understand your application is similar to what a
> > > torch height control would do. That would have no problem because
> > > you're moving short distances in (I guess) a not so high speed.

One microstep at a time, maybe 200 back and forth over 48" of z travel.

> > > But, I don't know if you tried the sim configs of external
> > > offsets. There's one in particular that lets you modify the signal
> > > fed into the eoffset and also the speed and acceleration of that
> > > particular simulated joint. To sum up, you clearly see how the
> > > phase shifts whenever you increase the amplitude of the signal or
> > > decrease the speed/acceleration of the sim joint. I'm just
> > > thinking how to avoid that phase shifting because all the parts I
> > > need to machine have a register on them, so it would be nice to
> > > mantain that angle in phase no matter what the RPMs on the spindle
> > > are. I think that to attenuate the signal is more than enough to
> > > compensate for an out of range speed/accel and avoid problems.

Well since the pi3 is a bit short of power to do that, I set up a slower 
thread at 200hz to do all the lower priority stuff, like servicing the 
jog dials that substitute for the hand cranks that aren't there anymore 
when I want to run it like a normal lathe.

Its worked so well I have had no urge to remove it once a pi4 was doing 
it. 

My one still major squawk is that none of that stuff updates the active 
axis radio buttons so I wind up doing touch offs to the wrong axis. I'm 
gradually training myself to manually do the buttons first before 
clicking on a touch off but its still damned frustrating. There ought to 
be a way to make that automatic in hal.

> > > I was thinking about doing an active phase compensation in HAL to
> > > compensate for the signal lag whenever the rpms change, but I
> > > suspect there's a more practical solution...

Perhaps theres a usable clue in the math that Sam has used to carve 
multi-faceted holes? That stuff is genuinely thinking outside the box. 
With the backgear engaged and my new much faster 3 phase stepper 
servo's, non-round shapes can be done on that lathe. Interesting idea to 
explore for sure.
> > > Glad to hear you're doing well Gene :)
> >
> > Not totally laid up, yet. But I'll be 87 very shortly, and the yard
> > work I was doing for about 3 hrs earlier will still be yelling at me
> > tomorrow. Getting old is not for the faint hearted, specially when
> > your ticker is running on a battery and already has rebuilt valves
> > just to keep it pumping at 30%. For me, thats good, and sure beats
> > the alternative.
> >
> > Besides, he is not ready for me yet, I'm too much of a maverik. ;o)
> >
> > Gabriel would send me down, I'd fix the stoker, install electricity
> > and airconditioning, start a brewery and open a bar...
> >
> > 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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> > [email protected]
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>
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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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