5 msec is not bad. In the olden days we ran on a 20msec position loop. So it will be inertia mismatch. I also battled my but off last year with a Deckel.
My solution for encoder noise is an RS485 connection and if it is still bad a computer screen cable ferrite (or similar) around all 8 cores of the encoder cable simultaneously. Cheers J. Sent from my ASUS MeMO Pad Gene Heskett <[email protected]> wrote: >On Tuesday 01 September 2015 15:35:38 Jan de Kruyf wrote: > >> Gene your filter theory might well be right. Because you add a >> measurable delay in the loop. >> >True, but best case is only 5 milliseconds, thats much faster than any >inertial effects. > >> The other thing I found is that the load inertia of a spindle is often >> badly matched to the motor inertia. This causes a real head ache >> setting up the pid. > >Yes, I'd have to assume that the motors armature is a much larger factor >in the rotating mass than the spindle itself unless a huge multiple edge >fly cutter was mounted. The geardown, even in high back gear, is at >least 3/1. > >> Feed forward of the signal might help in both cases, since then the >> feedback amplification needed is much less. > >pncconf set FF0 and FF1 to 1.0, which surprised me too. In my other >tuning I have quite often used 100 as FF0, meaning 100% of the input >command is sent to the output as a base. Pgain then is the major error >corrector, but here its doing almost all of it. FF1 is 1.0 IIRC. FF0 is >normally used herre to put the error so its straddling zero. 1.0 won't >do it. > >> Cant help you with all the variables you refer to. >> >> cheers, >> >> j. >> >Thanks Jan. > >[...] > >Cheers, Gene Heskett >-- >"There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." >-Ed Howdershelt (Author) >Genes Web page <http://geneslinuxbox.net:6309/gene> > >------------------------------------------------------------------------------ >_______________________________________________ >Emc-users mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
