On Tuesday 07 November 2017 04:48:56 andy pugh wrote: > On 7 November 2017 at 05:37, Gene Heskett <[email protected]> wrote: > > pid.N.command-deriv float in > > The derivative of the desired (commanded) value for > > the control loop. If no signal is connected then the derivative > > will be estimated numerically. > > > > What for instance, would/should be connected here, and what would be > > the desired result of such a connection? And in this context, what > > is a derivative? > > "Derivative" means "rate of change". > On a position servo loop you would connect the high-quality velocity > output from an encoder counter or resolver here, or the analogue input > value from tachometers. > In your case this would be spindle accelleration, and you don't have > any source of the signal that is a higher quality than the PID can > calculate for itself, so leave it unconnected. > > > pid.N.error float out > > The difference between command and feedback. > > > > This, on my G0704 seems to be a constant zero at any gain setting of > > the halscope. What is this trying to tell me? > > It is telling you that the pid.N.command and pid.N.feedback are > exactly equal, which probably means that you have wired the PID up > wrong.
They are not equal, not even close, measured at those pins on the pid with the halscope. Ergo there should be an error at the pid's error output pin even if its only a few microvolts. Its a flat, noiseless line on the scope. Even when the spindles rotation is being reversed. And frustration is rampant, so I've forgotten to thank the responders, so thank you all who have taken the time to respond. 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
