----- Original Message ----- From: "Jon Elson" <el...@pico-systems.com> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Friday, April 23, 2010 11:23 AM Subject: Re: [Emc-users] Bridgeport spindle encoder
> Andy Pugh wrote: >> As for speed signal noise, my speed signal is fairly random, (it is a >> home-made encoder ring with slot-sensors) but using the right PID >> values seems to filter that effect adequately. >> > Well, I guess I will have to try this out. >> I have just thought of another way of doing the same thing that might >> work, you could potentially make a "gasket with mounting tabs" with >> the sensors on the (folded down) tabs and the remainder clamped >> between the castings over the full mating surface. I guess that would >> depend on how critical the casting separation is, ie whether there is >> a bearing in the top cover or something else that "cares". > The direct drive clutch is between these two parts, so spreading them > apart very much would possibly make the clutch not engage at all. > > Jon > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users I use speed feedback on my lathe, filtered it using existing Hal functions. On threading my counter gets reset (spindle encoder) and would be an enormous negative speed, I limited the rate of change of speed to be realistic, I don't allow it to go from 800rpm forward to millions of rpm reverse in a millisecond. Instead of inputs for belt position and back gear, could you use a single index input on the motor and use the gear teeth that are counted between motor revolutions to calculate the ratio between the motor and spindle? Would their be a way to make the path hold up until the spindle was at 80% command speed? I've heard of EDM feeding based on voltage, thought maybe feed rate could be based on spindle rpm. Roger Neal ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
