On 01/08/2014 10:49 AM, Peter Blodow wrote: > Dave, > thanks for answering so promptly. Haven't got out the scope so far, but > that mustl be one of the next things to do. What do you mean by > resetting the phase between A and B? Some of the oldest linear glass scales had adjustable offset between the A and B sensors. I worked on one that had the same grating for the scale and the read head, and they tilted the read head grating to get the quadrature effect. This caused the light and dark regions to sweep across the sensor at right angles to the motion. It used a form of the Moire effect.
Most scales made since the 1970's have the 90 degree quadrature offset built into the glass pattern of the read head, and no adjustment is possible, other than angular alignment between scale and head. Jon ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
