On Friday 24 February 2017 00:08:42 Chris Albertson wrote: > I don't think it works this way. It does not power down. But it > does work exactly as per the specification. There are 100 detented > divisions per revolution. The A and B phase of course only change > when there is movement. > > In theory you can get 400 steps per rev but the wheel has detents so > there is no good way to move it to a place between the marks. > > This is OK because we get to define what "one revolution" means. It > one rev is 0.01 inches them each mark is 0.0001 Will can define it to > be inches or metric. The division are as fine or course as you like. > If you are building a user interface with this wheel I think what's > needed is a selector that defines what one revolution means. It will > also need a "zero" button and and axis selector > > My plan is to place a small micro controller inside the pendent with > the wheel and an LCD screen and some other controls. The uP will do > the translation.
Whereas I have i/o to throw away, so my LCD screen will be pyvcp tallys on the axis screen & hal modules doing the math. My dials will be mounted on the apron. Z lower left, X lower right. And my saddle will grow another piece of 3/8" OD SS pipe from the cable chain at the rear to the apron top for a piece of cat5 jumper cable I have yet to acquire. With 72 total I/O I can do some of that in hal. All predicated on me finding enough round tuits of course. I have a Dr's appointment this afternoon, a decent excuse to stop someplace and get some stranded "jumper" cat5 for the cable chain. I'll get one of the elderly girls across the street to come in and sit with Dee while I'm gone. > On Thu, Feb 23, 2017 at 6:31 PM, Gene Heskett <ghesk...@shentel.net> wrote: > > But I think its something we may be able to outwit in the hal file. > > > > They appear to have a power save shutdown, and a power up lag. > > > > And seem to have timings independent from each other. This is going > > to cause, unless we scale the encoder down by 4, one edge received > > occurs just as you start to turn it by hand, and again some > > milliseconds later after YOU have stopped turning the dial. When you > > stop moving it, it goes back to zero volts a few milliseconds later. > > > > This is looking at the A/B terminals, I have not yet checked the > > -A/-B terminals for their behavior. It may be that this problem may > > disappear if differential receivers with lots of histerisys(sp?, > > when do we get a spell checker that knows these technical words?) > > would just ignore this. > > > > But be aware its there guys if you feed it straight into the encoder > > module as is. You have effectively only those positions at rest > > corresponding to A,B=0. None of the other three combo's are > > available to you in the detent at rest condition. So you will move > > in a modulo4 at the start, and end of a move, always ending up in > > the 0/0 position when the wheel is at rest. > > > > I just checked the - terminals, it is not powering down, at rest > > they are both at the 5 volt rail. I was hopeing that we might have a > > true fine tune by using a straight edge went by=one motor microstep, > > but thats not going to happen, best we can do is one micro-step per > > detent felt. > > > > Now we know why such a precision looking and seemingly well built > > wheel was only a 20 dollar bill. ;-) You can only use 1/4 of its > > real resolution. > > > > Now I need to find some cat5 intended for jumpers, eg stranded wire > > for use in the cable chain to the saddle. But the last jumper I > > bought was made from flat cable. It works ok, but..., 8 wires isn't > > enough for everything either, I still need independent home > > switches, so thats 10. Sigh. When does it end and you can switch to > > use it mode? > > > > I did measure how far I can move the crossfeed in w/o exposing the > > ball screw, 3.35". Thats enough to put the tool tip on centerline, > > and work on something 6.7" in diameter w/o throwing swarf into the > > slot. Said another way, stuff will need to be zeroed and an air cut > > made to check if its still covered at the smallest diameter of the > > job. If not, move the toolpost mount, rezero, and cut some more > > air. > > > > 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 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
