Greg Bernard wrote: > Has anyone had experience with capacitive encoders? I found these while > browsing CNC4PC: > http://www.cnc4pc.com/Store/osc/product_info.php?cPath=64_78&products_id=363 > They seem to be very affordable. > > Yes, they look real good until you put them in a servo loop. They have a lag in responding to acceleration. You can look back in the archives and see some discussion of this. What I found is they can lag as much as 3-5 ms in responding to acceleration, and then produce velocities that greatly exceed the actual velocity so the position can catch up. Therefore, servo tuning can be difficult. I put one of these encoders on the same motor shaft as an old HP optical encoder and compared them in EMC2 and Halscope.
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