On Wednesday 21 July 2021 14:46:26 Chris Albertson wrote: > Could you solve the noise issue with a phase-locked loop? THis takes > advantage of the fact that the spindle has momentum and the > accelerating forces are limited. > > It is a common technique in electronics, you build a good, clean local > oscillator and then take your frequency measurement from that, rather > than from the noisy real-world data. But at the same time, you > compare the phase of the local oscillator with the real data and make > tiny adjustment to the local oscillator. > > What is really happening is that you only look at edges if they happen > near the expected time and weigh them, scoring to how near the > expected time so statistically almost all the noise is ignored. > > You can try averaging, but it does not work nearly as well and has a > long lag. > That I have tried, taking the sum of the last 4 edges, but the lag was showing and it was still too noisy to work well.
> On Wed, Jul 21, 2021 at 1:19 AM andy pugh <bodge...@gmail.com> wrote: > > On Wed, 21 Jul 2021 at 05:36, andrew beck <andrewbeck0...@gmail.com> > > > > wrote: > > > Andy what do you think is the max rpm that this will read reliably > > > do you think? > > > > It will handle a higher speed than a full quadrature setup as it > > only needs to see one edge. > > I have run it up to 16000 rpm (in the video) with a 50,000ns base > > thread. > > > > The problem with counter-mode is noise rejection, noise is seen as > > pulses and gets added to the position. (This isn't unique to the > > missing-tooth index, this is counter-mode in general) > > > > -- > > atp > > "A motorcycle is a bicycle with a pandemonium attachment and is > > designed for the especial use of mechanical geniuses, daredevils and > > lunatics." > > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > _______________________________________________ > > 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
