Steve Blackmore wrote: > On Thu, 01 Oct 2009 00:46:54 -0400, you wrote: > > > >> Steve should set up halscope as others have instructed. Capture >> position, velocity, and position-interpolated. Trigger on a falling >> edge of index-enable, so that the scope will take data at the beginning >> of a threading pass. Sample at the servo rate. You should be able to >> get 4000 samples, which is 4 seconds at the usual servo rate of 1mS. >> > > Here you go, three different shots taken during a G33 pass at 200 rpm, > 1.5mm pitch thread. > > http://imagebin.ca/view/db4r1Dnh.html > > http://imagebin.ca/view/XY9gDJ.html > > http://imagebin.ca/view/lUA3lv.html > The fuzzy band of encoder.0.velocity doesn't look unusal, but those big spikes are a cause for concern. Some of them are at least 3 times the width of the band. I can't tell where the zero is for that trace, so I don't know what the actual values are. I do notice (with some surprise) that these spikes don't seem to have a visible effect on the position reading.
In screenshot3, you can see the individual quantization of the velocity, and there, the spikes look quite anomalous. The big spike to the right looks to be at least 10 quanta high, probably more. That just shouldn't happen with a properly functioning encoder and regular sampling. A variation of +/- 2 encoder counts is required by the nature of sampling, and add another one or two for the vagaries of optical encoders. Any more than that says something is wrong. Jon ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
