On Wed, Oct 08, 2008 at 12:20:02PM -0500, Stuart Stevenson wrote: > John, > There are two pictures on www.mpm1.com:8080/cinci > one is the positive capture - the one that jumps - > positive-jumps.png > > one is both the positive and negative capture - > pos-neg.png > the positive on the left and the negative on the right > I moved the axis .0001 positive and then .0001 negative
It looks to me like the compensation is applied over .1 seconds with a velocity peaking at .05 inches/sec and acceleration of 0.5 inches/sec^2 (but someone should check my reading of the scope picture). In the ini it says the maxvel is 2.5 and maxaccel is 2.0, so I don't see anything obviously wrong at first glance. A jog or G0 move of .005 length seems like it would give you this same profile but at a higher acceleration. I wonder if maybe you just tuned the pid on longer moves and so these short moves when the screw is loose (not moving any table mass) might be badly handled by your tuning. By definition a backlash takeup move and ONLY the backlash takeup moves happen with the screw loose. (If anyone knows about screws loose, it's me, but that's another story.) ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
