On Wednesday 04 March 2020 12:52:09 andy pugh wrote: > On Wed, 4 Mar 2020 at 17:26, Peter C. Wallace <p...@mesanet.com> 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/44586b831e1ef5e826003190ab >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 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 Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
