Stephen Wille Padnos wrote: >> >> > Nothing has been removed, you would just use the stepgen in velocity > mode, with a PID driving it (making FF1=1 should give you the equivalent > of open-loop mode, plus or minus a step here and there). > > I have to retract my previous erroneous statement, after some more reading, Stephen is right (of course!) By running stepgen in velocity mode and using PID, you convert your stepper system into a true servo system. > > The real problem is that screw mapping is meant for systems that have > the screw between the feedback device and the table, but this machine > isn't like that since the scale is actually on the table. You can't > drive the PID very well with only scale feedback since it's too loosely > coupled to the motors, but that's irrelevant since you can't really use > steppers like servos anyway. > > An excellent point, the "screw error compensation" would not be correcting error on the LEADSCREW, it would be compensating for errors in the linear encoder, which may not be necessary at all.
Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
