I've learned to use the spinny knob on the BP Discovery 308 but at first missed the detent...
JT On 3/1/2017 10:57 AM, Roland Jollivet 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 ------------------------------------------------------------------------------ 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
