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
