> Yes, this confuses me, too. It may be that some other parameter is > actually causing it, and the I term either helps or doesn't help to > suppress the error.
With everything at 0 but P and D I get fairly low error. As I increase 'I' the error during cruise rises. If I is fairly low you can see the error increasing during cruise as the I term builds up. > error. One thing that can cause increasing error is when the servo runs > out of voltage. Nope. Flat out it will move at around 8m/min. I'm testing at around 3m/min. > A very slight increase in commanded speed will cause an extreme error, > and a slight reduction in commanded velocity will allow it to run longer > before error develops. That makes sense but it doesn't explain what I am seeing at cruise. If you are using this with some intelligent > drive, rather than a raw power amp, then the tuning parameters in the > smart drive can greatly complicate things. (I'm guessing with a P of > 1200, that is not a smart drive, though.) It is a plain PWM amp. The 5i20 generates the PWM. > I'm imagining a very-wrong FF2 setting that causes a large error at > the acceleration portion of the move. I'm currently testing with no FF1 or FF2. Any amount of FF1 increases the following error. I haven't tried FF2. > During acceleration, "I" > would wind up to push this toward zero. That is what I would expect. In practice I appear to be getting exactly the opposite. > Once you > have no appreciable error you can add plenty of I and it won't work > against you. But it WILL work against slowly changing conditions like > putting something heavy on the table or taking a heavy cut. I thought I was supposed to compensate to compensate for slowly changing or steady state loads. Thanks, Les ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/blackberry _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
