On Tue, 06 Oct 2009 10:25 +0100, "Andy Pugh" <a...@andypugh.fsnet.co.uk> wrote: > 2009/10/6 Jon Elson <el...@pico-systems.com>: > > > I think the basic problem is that the encoder count is by necessity > > granular, > > and a lower INPUT_SCALE "magnifies" that granularity. > > Is 'encoder.X.position-interpolated' inappropriate in this situation? >
Don't use position-interpolated as feedback for position control. Period. It even says that in the manual (I think). The problem is that as speed approaches zero, and reverses, the interpolator keeps guessing at the position until it sees the next encoder count. Those guesses will drive the PID loop nuts. The interpolated position output is intended mostly for threading, or any other application where some slave axis needs to track a master, and the master speed is more-or-less constant. There WILL be errors if/when the master speed changes abruptly or reverses, which a normal machine axis does all the time. Regards, John Kasunich -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ 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
