On Mon, 2008-03-10 at 22:38 -0400, Stephen Wille Padnos wrote: > Kirk Wallace wrote: > > >On Sun, 2008-03-09 at 16:29 -0700, Curtis W. Moore wrote: > > > > > >>If I added pulses can it be done? My encoder is just a homebuilt opto > >>switch. Cutting out a new wheel with more slots/holes would be trivial. > >>Can EMC thread with just one train of pulses? Ie use just one pin of > >>the parallel port? > >> > >> > > > >Just in case, the parallel port is fairly limited in speed. I am > >guessing 20 to 30 kHz is maximum. If you make a disk, the number of > >slots per revolution will be limited to something like 30kHz/3k RPM = 10 > > > > > [snip] > Note the common thinko here: 3k RPM is not the same as 3k RPS. > > 3kRPM = 50 RPS, so if you assume 30 kcounts/sec, you have 30000 Hz / 50 > = 600 counts/rev to play with. > > - Steve
&*%$#& it, I've been doing this all day. Thanks for correcting me. Someone might have taken it as being correct. "Question everything" seems to be good advise. Plus, writing out your units in equations. I would think 50 slots per revolution would be plenty, making 200 quadrature counts per revolution, so with the correction, we go from being on the edge to being well within limits (10 kHz (?)). For Penance, I should build an encoder and test it. Let's see, a 3" disk is ~ 9" in circumference, 9"/50 = .180" slot width, piece of cake. Although, I seem to remember someone has a bright yellow lathe with a disk like this. -- Kirk Wallace (California, USA http://www.wallacecompany.com/machine_shop/ Hardinge HNC lathe, Bridgeport mill conversion, doing XY now, Zubal lathe conversion pending) ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
