On Saturday 07 June 2014 22:11:52 andy pugh did opine And Gene did reply: > On 8 June 2014 03:05, a k <pccncmach...@gmail.com> wrote: > > change voltage from 0 to 5 change encoder velocity to 20% ( from 0.78 > > to 0.79) > > with this range of 20% how i can change feed from 0-150%? > > Something here isn't making sense. the THCAD ought to be linear. > > If you connect a voltmeter to the THCAD inputs, what do you see? > > I don't see how 20% and 0.78 - 0.79 are the same thing. That sounds > like 0.012%
If that is the voltage at the summing junction, its entirely believable. And in my experience feeding the summing junction direct, is a huge source of non-linearity in control. I have gained usable linearity by feeding the pwm to analog voltage into the motor controller thru a 100k ohm resistor. I of course do not have any experience with the THC card, so could be way off base. Just throwing it out to see if it sticks. ;-) 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> US V Castleman, SCOTUS, Mar 2014 is grounds for Impeaching SCOTUS ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. Written by three acclaimed leaders in the field, this first edition is now available. Download your free book today! http://p.sf.net/sfu/NeoTech _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
