On Saturday 09 January 2021 20:57:24 Jon Elson wrote: > On 01/09/2021 06:39 PM, Gene Heskett wrote: > > Yes so idb drives it closer by overdriving it an "amount" so that > > the friction locked point is closer to the desired point without > > going over. The trick is to null the error without changing the sign > > of the error. If the sign changes, then it oscillates, hard. So you > > can narrow the friction caused deadband by a small amount of > > overdrive, but you also cannot change the sign of the error. > > Yes, that's the tricky part. Any time you introduce a > discontinuity into the transfer function, > it makes things unstable at that point. > > Jon
Thinking along a different line, I am running the pwmgen at 4khz, mainly because my ears have a "carhart notch" at least 120 db deep so theres not a chance in hell I'd ever hear it. What would happen if I dropped the pwmgen frequency to 400 hz. that same percentage of a pulse coming into the controller would have 10x the length of time to actually move the motor, which may drive it closer to a null than tickling it with a 1% pulse 4k times a second. The trouble with that is that both pwmgens run at the same frequency, and Jon's servo, driving the spindle, may trip its current limits with the longer pulses. Jon? Can you opine on that? Is there a minimum frequency for those toroids? Thanks. > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
