On Sunday 04 April 2021 14:35:46 Jon Elson wrote: > On 04/03/2021 11:39 PM, Sam Sokolik wrote: > > Initially I would just try 'and-ing' the 2 in hal or classic ladder > > and run strait to the home input. (Not using the home to index) > > If the prox sensor is of very short duration in linear > motion, then the AND will just pop on for a moment, and > likely go past it on the initial home search. That will > likely confuse the homing sequence. But, you can try it. > > Jon > If that is the case, its missing a very narrow index, and your switches or index is a ground pulse, I have made that super dependable for my probing operations by adding a .05 uf cap to ground across the probe contact. That way, when probing and the probe contact wire is rotating in the spindle, the wire is effectively made into a perfectly round cyclinder, if it touches the work at any point in its rotation, the capacitor will be discharged and will stay at a logic low long anough to be detected by the 1 kilohertz servo thread. I run probes at an initial search of 2 or 3 ipm, when contact has occured, I back away 10 to 20 thou and come back at .1 ipm, and thats the one I record. I can find the middle of a hole with a repeat tolerance of .0002" or less. My ball screws have more backlash than that.
This same idea of a capacitor could very easily be applied to the index signal, by inserting a diode between the encoders index so that it can discharge the cap, but the active pullup in the encoder can't recharge it fast enough that its missed by the 1 kilohertz servo thread. > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers 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-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
