On Mon, Nov 29, 2010 at 3:32 PM, Kirk Wallace <kwall...@wallacecompany.com> wrote: > On Mon, 2010-11-29 at 14:43 -0500, Colin Kingsbury wrote: >> It's not magic and won't make the machine "more precise," but it would make >> it >> more fault-tolerant and that seems significant. > > Maybe not tolerant, but it's nice to get a warning when a step or two > are missed and otherwise is not obvious.
I think it would be better than a warning---let's say you set an excessive feedrate; the tool will still cut some material on a failed step, so repeating it might finally bring the tool into the desired position. If an encoder provides a reliable feedback, it could result in a machine that misses steps but maintains precise position control. Of course there are situations when repeating the failed step sequence isn't going to improve anything (e.g. resonance). Even then, early indication of a following error lets the machine change the move parameters before the part is ruined. The main difficulty is conceptual: stepper motor systems were always based on number of steps being the control variable. With encoders in the mix, do we keep steps as the main control variable and use encoders as a cross-check and/or a failure detector, or do we switch to encoders as a primary feedback source, or do we switch between them depending on some criteria?? ------------------------------------------------------------------------------ Increase Visibility of Your 3D Game App & Earn a Chance To Win $500! Tap into the largest installed PC base & get more eyes on your game by optimizing for Intel(R) Graphics Technology. Get started today with the Intel(R) Software Partner Program. Five $500 cash prizes are up for grabs. http://p.sf.net/sfu/intelisp-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
