On Monday 10 June 2013 10:05:54 dave did opine: > On Sun, 2013-06-09 at 22:05 -0400, Kent A. Reed wrote: > > On 6/9/2013 9:08 PM, Jon Elson wrote: > > > Gene Heskett wrote: > > >> Looking at its voltage output, with the motor disabled so there is > > >> no feedback,off = 0.125 volts > > >> click fwd button= 0.382 diff = 0.257 > > >> click + button = 0.942 diff = 0.560 > > >> click + again = 1.584 diff = 0.642 > > >> click + again = 2.302 diff = 0.718 > > >> click + again = 3.094 diff = 0.792 > > >> click + again = 3.970 diff = 0.876 > > >> click + again = 4.940 diff = 0.970 > > >> click + again = 6.04 diff = 1.100 > > >> click + again = 7.33 diff = 1.29 > > >> click + again = 8.88 diff = 1.55 > > >> click + again = 9.90 diff = 1.02 > > > > > > URK! It isn't even monotonic! That is harder to fix with a > > > piecewise-linear > > > interpolation. (Some simplistic codes won't handle that.) > > > > Ummm, I expect you mean the differences aren't monotonic, Jon. > > > > Actually, plotting Gene's data as a set of twelve points X, V where X > > is the number of clicks, I get a pretty decent graph --- looks like a > > parabolic curve opening upward, with a bit of a burble in the next to > > last point (or last two depending on how you look at data). > > > > Trying a second-order curve fit (using the free tool simfit, but > > there's lots of other tools) got me a decent looking result with a > > plot of residuals that also gives the impression that the last two > > points are questionable compared to the rest. > > > > I don't chose simply to post the results because I don't believe any > > single experimental run is sufficient. Repeat this experiment three or > > more times, Gene, so we can begin to get an idea of the quality of the > > data and then we can talk. > > > > Regards, > > Kent > > Except for the last point that looks like it should fit as a 2nd order > polynomial. Since we can to a considerable amount of calculation between > servo cycles calculating a simple polynomial should be simple and fast. > > Dave
The last data point is smunched because thats all the C41 can output after I had changed a 2.7k resistor out for a 12k resistor in an effort to get the no pulses voltage low enough to reset the zero speed at power on safety of the controller I'm using. I expect I can paste another 12k across that one and still satisfy that logic since with the 2.7k I had there originally, the off voltage was only .257 volts. With the 12k, its .125 volts when off. But this is a separate thread and I should have changed the subject line when I started discussing a PFM control method. My bad,middle of the night musings & what ifs. :) Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! My views <http://www.armchairpatriot.com/What%20Has%20America%20Become.shtml> You need tender loving care once a week - so that I can slap you into shape. -- Ellyn Mustard A pen in the hand of this president is far more dangerous than 200 million guns in the hands of law-abiding citizens. ------------------------------------------------------------------------------ How ServiceNow helps IT people transform IT departments: 1. A cloud service to automate IT design, transition and operations 2. Dashboards that offer high-level views of enterprise services 3. A single system of record for all IT processes http://p.sf.net/sfu/servicenow-d2d-j _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
