Gene, I think you are misreading the data sheet. The 115K baud is for setting up the unit. Ie. Pulses per rev. Once that's done the serial isn't used anymore. I had two US Digital opticals on my DC servo's and they were crap. I switched to CUI units and all my problems went away.
One has to assume the data sheet is correct when they say 8000 RPM with 2048 PPR. The 115k Baud has nothing to do with that. In either case, I'll likely set this encoder up for 200 PPR so that even with micro-stepping I really still don't care for higher resolution since I have a 25:1 planetary drive after the motor. Assume I run the motor at 600 RPM max speed. That's 10 RPS or 2000 pulses per rev or 20,000 with 10:1 micro-stepping. But wait... 600 RPM divided by 25 is 24 RPM or 0.4 RPS so 2.5 seconds to turn one revolution. I'm thinking that if it takes 1 turn to release a TTS holder that's still 2.5 seconds. Faster than me with a couple of wrenches. And 25 seconds for 10 turns to release an R8 holder. Also faster than me mucking with the nut. Unless I would use an electric drill to spin it loose. But then think of the process. 1. Pick up two wrenches and loosen draw bar. 2. Put down wrenches. 3. Pick up portable drill and spin draw bar. Now maybe impact drill could do both. 4. Once 10 turns are complete catch R8 tool. Twenty five seconds for it to be done automatically is actually not so bad. John > -----Original Message----- > From: gene heskett [mailto:ghesk...@shentel.net] > Sent: July 29, 2023 10:37 PM > To: emc-users@lists.sourceforge.net > Subject: Re: [Emc-users] Drilling holes in the back of a stepper motor > > On 7/30/23 00:12, John Dammeyer wrote: > > Hi Gene, > > Best answered with the data sheet. > > https://www.cuidevices.com/product/resource/amt11.pdf > > > A Capacitative device. Not a hall effect. The capacitative may be faster > than a hall. The reason I'm anti hall is the time lag in the hall world > due to the time it takes to do the A/D conversions, which in turn means > the hall encoded setup moves in jerks depending on the speed of that > conversion. The 42C series of small motors, seen as ideal for a 3d > printer, are a disaster because they don't move step by step but jerk by > jerk, frequency of jerk determined to the speed of the A/D. Optical can > determine where the motor is and which direction its turning from any > edge of either A or B signals. At sufficient microstep divisors they can > move quite pretty smoothly. I'd assume this time lag in less for the > capacitative, but at the same time there is the Nyquist effect but the > capacitative conversion is simpler, but the serial output still enforces > a lag in the data stream. Only optical, which at higher and fixed > resolutions is instant. The question remains then "is capacitative fast > enough". And that IDK. The 115 kilobaud output says no to me. That > alone would make me go shopping for a ABI encoder. > > But I'm known to be picky. That's an optical $22 Omron 1000 ppr on the > back shaft of the 1 hp in my g0704. With the gear ratio being > switchable, and that encoder rated for 6k revs, but I watch spindle revs > in the tach display. Top spindle is 3k revs. So times a hair over 7100, > its seeing motor revs of nearly 21k revs at full song and not missing a > beat for about 5 years now. Scale for high gear is a hair over 7100 per > spindle rev. I don't use the index, that is generated by a screw glued > to the spindle going by an ATS-667 hall effect. That has its own > direction problem I'm not smart enough to fix. Someday... > > > Not cheap in Canadian $. > > https://www.digikey.ca/en/products/detail/cui-devices/AMT113Q- > V/4835229 > > > > John > > > > > >> -----Original Message----- > >> From: gene heskett [mailto:ghesk...@shentel.net] > >> Sent: July 29, 2023 9:02 PM > >> To: emc-users@lists.sourceforge.net > >> Subject: Re: [Emc-users] Drilling holes in the back of a stepper motor > >> > >> On 7/29/23 22:36, John Dammeyer wrote: > >>> Here's my solution. Drilled and milled 0.065" aluminum. Two counter > > sunk > >>> holes in the back. The modified flat head screws epoxied in serving as > >>> threaded studs. Then followed standard CUI installation and alignment > >>> instructions. > >>> > >>> Now to interface to it and write software to capture the motion and > >> position > >>> John > >>> > >> Just one question John, is that encoder optical, or hall effect? > >> Optical is real time, hall effect is not. > >>> > >>>> -----Original Message----- > >>>> From: Curtis Dutton [mailto:curtd...@gmail.com] > >>>> Sent: June 26, 2023 6:28 PM > >>>> To: Enhanced Machine Controller (EMC) > >>>> Subject: Re: [Emc-users] Drilling holes in the back of a stepper motor > >>>> > >>>> On a past life before I started using servos I had attached encoders to > > my > >>>> steppers to stop the machine when steps were missed. I used us digital > >>>> encoders that came with adhesive backed mounts from the factory. > They > >>>> worked swimmingly. I still have one in the "spare parts" room. The > >> encoder > >>>> is still securely attached over 10 years later. "double sided tape" > >>>> essentially woked very well. > >>>> > >>>> On Mon, Jun 26, 2023, 3:11 PM Todd Zuercher > >> <to...@pgrahamdunn.com> > >>>> wrote: > >>>> > >>>>> I was just about to suggest gluing the thing on. You beat me to it. > >>>>> > >>>>> Todd Zuercher > >>>>> P. Graham Dunn Inc. > >>>>> 630 Henry Street > >>>>> Dalton, Ohio 44618 > >>>>> Phone: (330)828-2105ext. 2031 > >>>>> > >>>>> -----Original Message----- > >>>>> From: Roland Jollivet <roland.jolli...@gmail.com> > >>>>> Sent: Monday, June 26, 2023 1:17 PM > >>>>> To: Enhanced Machine Controller (EMC) <emc- > >>>> us...@lists.sourceforge.net> > >>>>> Subject: [Emc-users] Drilling holes in the back of a stepper motor > >>>>> > >>>>> [EXTERNAL EMAIL] Be sure links are safe. > >>>>> > >>>>> You have such a large flat surface area there. Design an encoder > mount > >>>>> plate of similar size where the end result is also has a flat surface. > >>>>> > >>>>> Rough and clean the back of the motor up, then use a decent > >> polyurethane > >>>>> adhesive to bond it on. During the setup you could use a jig to keep > > it > >>>>> concentric with the shaft. > >>>>> Design it in such a way that you can still replace the encoder if need > >>> be. > >>>>> > >>>>> Roland > >>>>> > >>>>> > >>>>> > >>>>> > >>>>> On Sun, 25 Jun 2023 at 05:31, John Dammeyer > >> <jo...@autoartisans.com> > >>>>> wrote: > >>>>> > >>>>>> I want to add an encoder onto the back of this stepper motor. I can > >>>>>> install either a US Digital or a CUI since both mounting flanges can > >>>>>> extend out near the edges of the back mounting plate. > >>>>>> > >>>>>> > >>>>>> > >>>>>> Is there any reason I can't clamp the motor in a vice and pop in two > >>>>> holes > >>>>>> and tap them with a bottom tap at the spacing of the mounting > flange? > >>>>>> > >>>>>> John > >>>>>> > >>>>>> > >>>>>> > >>>>>> _______________________________________________ > >>>>>> 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 > >>>>> > >>>>> > >>>>> _______________________________________________ > >>>>> 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 > >>>> > >>>> > >>>> _______________________________________________ > >>>> 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 > >> Genes Web page <http://geneslinuxbox.net:6309/> > >> > >> > >> > >> _______________________________________________ > >> 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 > Genes Web page <http://geneslinuxbox.net:6309/> > > > > _______________________________________________ > 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
