Gene, You've been so helpful in the past I thought I'd pass the attached round tuit on to you. John
> -----Original Message----- > From: Gene Heskett [mailto:[email protected]] > Sent: October-13-21 9:42 PM > To: [email protected] > Subject: Re: [Emc-users] Fwd: Fwd: Rogue Index Pulses > > On Wednesday 13 October 2021 21:09:54 Chris Albertson wrote: > > > You are right, but under all conditions, the resistor connecting the > > wire to ground through a diode has lower impedance than the same wire > > terminated at a transistor gate as was the case before. The proof is > > that it works now. > > > > The other thing was thinking is that it should be simple to use > > software to filter out a ghost pulse from an encoder. After all, we > > know that it can only happen once per revolution. We could look at > > the counter that racks A/B quadrature pulses and know it is is time > > for an index. Software could do this even with no configuration by > > spinning the shaft. In fact verifying that the index pulse always > > happens at the expected time is a great way to error-check that no > > counts were dropped or added. It would be a great self-dignostic. > > I think I have the bones of such in at least 2 of my .hal files already. > > In order to establish the "SCALE" for this or that, I put in a method to > measure 100 occurances of an index, and calculating that SCALE factor by > recording the encoder count at the 3rd index, then recordiing the count > at the 103rd index, and dividing that resultant difference by 100. I've > done that three times now on the G0704, once for the two gears of the > spindle, and then for the BS-1 as an A axis. That essentially same hal > circuit could be used to gate the index, allowing an index to enter only > if the difference says its due to occur. I used a different math in the > A case because the figure I wanted is exactly a degree, not a 360 degree > turn. > > This code works well in either case. I will use that same hal construct > to calibrate the A on my 6040 when I take the A axis currently on the > kitchen counter with my harmonic drive mounted on it, back to the 6040 > and re-install it. The OEM version was 100x faster than it needed to be, > and had virtually no holding power. I made the harmonic drive as a 30/1 > but practicality says I should redo it as a 20/1, its a bit slow because > the belt drive ratio is 21 to 83 in addition to the the 30/1 in the > drive. More teeth on the output pulley might find me a tight enough belt > to not need an idler as there virtually no place to put it that is now > rigid enough. The belt problem is that they are not made in arbitrary > sizes. So I should obtain the next longer belt, and expand the output > pulley tooth count until its tight enough w/o an idler as the shaft > separation is not adjustable. > > That project is waiting for me to find my round tuit and print a belt > tensioning idler bracket that does work. Or adjust as described above. > > 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 > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users
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