My first try at machine control used linear scales. They worked but I had 0.0025 backlash in X and Y and the control got considerably smoother when I put a good incremental encoder (10K counts/rev and a pitch of 4) on the ball screw. The tuning was also much easier. IIRC Stuart is using the linear scale to drive I of the pid to force final position. This would seem to be the ideal configuration.
Years ago a Boeing engineer stated that machine resolution should be 5X better than the tolerance(s) you are trying to attain. Just my tuppence. Dave On Sun, 2011-09-04 at 21:41 -0500, Jon Elson wrote: > Jan de Kruyf wrote: > > 20 or 25um with a multiplierbox to make 1um has been pretty much > > standard for many years. > > > First, you need analog scales to use an interpolator. Digital-output > scales can't be interpolated. > Then, in many cases, the interpolators cost several times what the basic > scale costs. Finally, the > interpolator has to have fast response, any delay in reporting counts > will cause erratic servo > loop response. > > Jon > > ------------------------------------------------------------------------------ > Special Offer -- Download ArcSight Logger for FREE! > Finally, a world-class log management solution at an even better > price-free! And you'll get a free "Love Thy Logs" t-shirt when you > download Logger. Secure your free ArcSight Logger TODAY! > http://p.sf.net/sfu/arcsisghtdev2dev > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Malware Security Report: Protecting Your Business, Customers, and the Bottom Line. Protect your business and customers by understanding the threat from malware and how it can impact your online business. http://www.accelacomm.com/jaw/sfnl/114/51427462/ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
