Tom wrote: > Question: > If I tune the PID for the lowest following error while making the buzzing > sound > (sawtooth trace) go away, (and set MIN_FERROR & FERROR accordingly), but then > if I am not happy with the accuracy of my cuts at normal feedrates (20-70 > ipm), > will I then need to change to higher count encoders? (Currently Renco 500 > line > / 2000 ppr) > What is your count resolution (in the ini file, that is INPUT_SCALE)? Just guessing an encoder directly mounted on a 5 TPI leadscrew, that is 5 * 2000 = 10,000 counts/inch or 0.0001" per count. That is definitely on the low side. I am using 20,000 counts/inch on the X and Y of my Bridgeport, and it works, but doesn't give the tightest control. But, these were the encoders I could afford at the time (1000 cycle/rev, 4000 counts/rev).
If you are not using FF1 and FF2, you should really explore them, they can help IMMENSELY. If you are, then increased encoder resolution should help. I know that I can tune my minimill, with the 128,000 counts/inch, to insanely small following error. Far less than the real errors (backlash, screw pitch errors, etc.) Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
