Stephen Wille Padnos wrote: > EMC can do PID just fine. It's steppers that can't. Steve makes many good points, which have been gone over ad infinitum here over the past N years.
The only comment I want to throw out is that some users actually ARE using encoders with stepper motors. It won't really correct for lost steps except in some very special cases, where these errors ought to be fixed by other means. But, in a stepper system where lost steps are a rare event usually caused by a chip in the leadscrew or a real crash into a fixture, it can save you from ruined workpieces or hours of checking parts with a micrometer. I want to agree with Steve that a linear scale doesn't magically solve backlash except maybe in positioning-only applications. Backlash is a much more fundamental problem, meaning that the machine table is not constrained by the leadscrew, and no attempt to gloss over it with software will make that lack of constraint disappear. It will bite you when you get into more advanced machining. Jon ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
