Yet another situation where more is less.. ;-) In a more perfect world I guess it might be best if everyone was running 1024 ppr encoders on their spindles and threading at 1000+ rpm and using a hardware interface.
Ironically if you want to thread on a really large lathe and need to run at 60 RPM to do so, the position interpolated functionality would really be required. Don't laugh at the 60 rpm, I am helping a guy on a big lathe CNC lathe that can run much slower, I think 9 rpm is the lower limit on the spindle. Crazy slow. :-) Dave Andy Pugh wrote: > 2009/10/23 Jon Elson <el...@pico-systems.com>: > > >>> Which is an interesting point. It seems that a hardware quadrature >>> counter is likely to be counterproductive if you have a low-count >>> encoder. >>> >>> >> I'm not sure it is COUNTER-productive, but if the spindle encoder >> resolution times >> the maximum spindle speed doesn't exceed the ability of the software >> encoder counter, >> than it doesn't GAIN anything. >> > > Perhaps I should have elaborated further. What I was saying is that if > the hardware encoder and driver does not offer an interpolated > position every servo cycle and the encoder pulse rate is low enough to > have multiple servo threads per encoder count, then EMC will see a > stationary spindle with the hardware encoder. This might cause the > problems we are seeing. > > In that situation the software encoder, which does offer > position-interpolated, is paradoxically superior. > > ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
