On Friday 24 November 2017 11:04:16 Peter C. Wallace wrote: > Why dont you just make an index mark/pointer on the headstock and > chuck This should be hand settable to less than a degree of chuck > motion then just note the motor encoder count when the chuck is > aligned with the mark and then rotate the motor until the chuck has > turned say 20 turns. This should give you the ratio to within 1/7200 > which should be better than needed. if thats not enough, just do more > turns, you could get to PPM accuracy is less time than it takes to > futz with doing this is hal > > Peter Wallace > Mesa Electronics > Ok Peter, now I am running out of patience. The %$#@&^%ing opto's on this bob are about 3 damned decades too slow to work with this encoder. Just to get it to run under its own power, I had to reverse the a/b channels, and take the decimal point out of the existing scale settings for the old shop-made encoder, so now I can see that the motor is at least under pid control, up to about a spindle rpm of about 100 revs. Above that, the opto's fail, I think to turn off. And the spindle takes off from lack of feedback. This encoders high level isn't enough to turn the led in the opto's off quickly, about 4.4 volts so its still sinking some current. Goes down to a hundred millivolts for a zero.
So I'm off in search of a bob that will work. If Leonardo was still making the latest C1G, that would be ideal, but that fell out of his catalog a couple years ago. Besides, its waaaaay too big physically. Or, tear it down, remove this bob, and rip out the encoder channel opto pair. I've already done that to the pwm controlling the spindle, getting rid of 99.9% of the non-linearity. Do you have anything that small? Maybe like Leonardo's (cnc4pc) C10s but with better connectors? > ---------------------------------------------------------------------- >-------- 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 > 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) 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
