I don't know - maybe over-thinking this a bit? I have 2 machines using gear tooth sensors. Both rigid tap perfectly without issues.
http://electronicsam.com/images/matsuura/sensors1.jpg On Thu, Mar 31, 2022 at 8:32 AM gene heskett <ghesk...@shentel.net> wrote: > On Thursday, 31 March 2022 07:57:53 EDT andrew beck wrote: > > For those interested I decided I really should start to use the forum > > so people can search later for stuff hopefully I help someone. > > > > I have started on the gear sensor style encoder. > > > > > > Hope it works. Let me know your thoughts > > > > https://forum.linuxcnc.org/show-your-stuff/45498-linuxcnc-machine-shop-> > fun-thread > > > > Regards > > > > Andrew > > > > On Sun, 27 Mar 2022, 22:21 Andy Pugh, <bodge...@gmail.com> wrote: > > > > On 27 Mar 2022, at 08:09, andrew beck <andrewbeck0...@gmail.com> > > > > wrote: > > > > > > > > And is bigger dia better for higher resolution? > > > > > > Probably not, as it will perhaps have more scope to oscillate at > > > 10,000 rpm. > > > > > > Don’t neglect the purely mechanical design of this fast-spinning > > > part. > > > > > > Have you considered optical sensors rather than inductive? > > > > > > What will be counting the pulses? > > > > > > LinuxCNC can lathe-thread with one sensor. > > > But rigid-tapping is different as it needs to accurately detect the > > > reversal point. So you need three channels for index and full > > > quadrature. > > And this is the problem with useing an ats-667 gear sensor. It switches > on the approach, so the switch point, in only watching one edge, will > have a different switch point depending on the direction. Some day, I've > got the fix that. Needs a circuit from the quad detectors direction > output, to dynamically switch the polarity of its pulse depending on > which direction the quad detector says its turning. Thats active > circuitry and needs to be MUCH faster than a hal thread. Probably in pure > hardware. Ideally for that, an edge detector watching and firing on both > edges with the first one "cocking" a trigger, and the second pulse then > gated to the index circuit. That way the pulse seen as an index would be > the one generated as the center of the trigger tooth is passing over the > center of the ats-667. The ats-667 stays in that state until the next > trigger is aproaching. So turning in one direction, its on 96% of the > time, but in the other direction its off 96% of the time. > > > > Work out what error you can accept in the reversal point detection > > > (as a fraction of thread pitch) and you can get a feel for how many > > > slots you need. > > > > > > > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > > 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, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > > > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
