On Thu, 5 Mar 2020, Gene Heskett wrote:
Date: Thu, 5 Mar 2020 10:42:19 -0500
From: Gene Heskett <[email protected]>
Reply-To: EMC developers <[email protected]>
To: [email protected]
Subject: Re: [Emc-developers] 2.7.15 PID Fix
On Thursday 05 March 2020 09:25:01 Peter C. Wallace wrote:
On Wed, 4 Mar 2020, Gene Heskett wrote:
Date: Wed, 4 Mar 2020 22:12:47 -0500
From: Gene Heskett <[email protected]>
Reply-To: EMC developers <[email protected]>
To: [email protected]
Subject: Re: [Emc-developers] 2.7.15 PID Fix
On Wednesday 04 March 2020 12:52:09 andy pugh wrote:
On Wed, 4 Mar 2020 at 17:26, Peter C. Wallace <[email protected]>
wrote:
It was first added to 2.8 and them merged into 2.7 before the
2.7.15 release AFAIK
I think that they were added in 2010:
https://github.com/LinuxCNC/linuxcnc/commit/44586b831e1ef5e82600319
0ab 317cda76b6e8e3#diff-912d11dfa52738be509f63e4ff1922a4 (And that
commit also includes documentation of the pins)
Sort of. But it does provide some hints as to how to utilize it to
improve control, If you have encoder feedback on axis axis then you
could feed the feedback.deriv pin with the velocity of that axis's
encoder. But from reading that, I fail to deduct a source for
cmd.deriv. I am envisioning a differential, for instance between
current command and previous command or maybe a sum2 with one input
set for a gain of -1 and an rc lag from the command input to the
other input giving a differential output according to the charge
across the cap. Since we don't have a cap in hal components, we'ed
have to use a low pass. But I quickly run out of imagination as to
the rc time constant to synthesize.
just discussing the howto's would I think be educational for those
of us who never got the transcendental stuff in school 70+ years
ago.
Help?
Thanks
Normally you would just connect the joint velocity pin to the PID
command derivative
Ok, but thats the signal I disconnected around 2 years back to get rid of
an instant following error for a movement of 1/10 the MIN_ERROR. So
hooking it back back up now does what to my FF# settings?
It requres somewhat different tuning because of differening delays
in the TPs idea of velocity and velocity calculated in PID via DP/DT
Changing anything now is likely a waste of time
Cheers, Gene Heskett
--
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-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law
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Peter Wallace
Mesa Electronics
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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>
_______________________________________________
Emc-developers mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-developers
Peter Wallace
Mesa Electronics
(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination.
_______________________________________________
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