Oh, you are planning to MAKE the encoder? You can always salvage one off an old printer or copy machine. I've found encoder wheels with thousands of divisions and the optical sensor to read them. Also you can find good plastic gears and you can make a geared encoder that runs faster then the hand wheel or even use the gear teeth and two gear tooth sensors as the encoder.
On Wed, Mar 1, 2017 at 8:57 AM, Roland Jollivet <roland.jolli...@gmail.com> wrote: > I thought that if 100 detents and 1tick/detent was all that was needed, > then it would be simple to make. 400 ticks/rev is still do-able, but > anything above that means a purchased encoder, and then the incentive is > lost. > > I think the detent is invaluable where any overshoot will crash the tool. > > > > > On 1 March 2017 at 18:31, Chris Albertson <albertson.ch...@gmail.com> > wrote: > > > I think when you design one of these you have freedom to define the > > mechanical detents per revolution and the number of encoder "ticks" per > > revolution independently. You are arguing for these numbers to always > be > > the same. But why? Why not 10 ticks per detent? I think with a jog > > wheel the higher the ratio the better. Four is better than one. On > the > > one to one case it is likely the machine (milling table) will jump in > steps > > as fast as the motors can move then stop at each detent. In the 10 to > one > > case the table would move only as fast as you turn the dial between > > detents. > > > > I'm wondering why there are detents. I don't see much reason for having > > "clicks" in the wheel. My preference would be to design the wheel > using > > "damping grease" so I'd have a wheel then turns smoothly with bit of > > friction that stays put when you release it. And to have the encoder be > as > > fine as possible, Maybe even optical with 4096 "ticks" per revolution so > it > > would have an analog feel. In this case that ratio would be 4096/0 or > > infinity ticks per detent. MUCH higher then four or ten. > > > > > > > > On Wed, Mar 1, 2017 at 4:42 AM, Roland Jollivet < > roland.jolli...@gmail.com > > > > > wrote: > > > > > I had always assumed that machine MPG's generated one state change per > > > click, but following Gene's discussion, I pulled out my 1988 Fanuc MPG, > > and > > > saw that it was also 4-states per click. Obviously, one 'pulse'/detent > > > > > > Does anyone know the rationale behind this? > > > I assumed one always wants one step per click, so why not use a 25ppr > > > encoder and use every change? > > > Used as currently is, it would have to be a software /4 to be useful. > You > > > could also do a /2 or /1, but no-one ever wants a x2 or x4 on their MPG > > > It's always x10, x100 or whatever, so the count/detent would always > have > > to > > > be n/4 x 1 .. or.. n/4 x10 in software. > > > > > > Alternatively, if I was going to make my own MPG, surely I would just > > make > > > a 25ppr encoder and make it 1 detent/change? > > > It's far easier for me to make, so surely it would have been for Fanuc > > too? > > > > > > What am I missing? > > > > > > Regards > > > Roland > > > ------------------------------------------------------------ > > > ------------------ > > > 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 > > > > > > > > > > > -- > > > > Chris Albertson > > Redondo Beach, California > > ------------------------------------------------------------ > > ------------------ > > 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 > > > ------------------------------------------------------------ > ------------------ > 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 > -- Chris Albertson Redondo Beach, California ------------------------------------------------------------------------------ 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
