Andy Pugh wrote: > [snip] >> Would my 4 magnet set-up through a second pickup provide that, if a >> timing pulse is required , or is that too coarse? >> > More pulses is better, but a few inaccurately-times pulses is probably > worse than 1PPR for introducing errors to the spindle velocity > calculation. > Note that you need a separate index if you have more than one pulse per revolution on phase-A. You can have more or less any number of counts per rev for the encoder/counter (just set the scale correctly), but there must be exactly one index per spindle revolution.
As for timing, I think you'd end up with a little bit of a sawtooth from the interpolated-position output. Skewed sensors basically make the timing roughly alternate between "a little long" and "a little short". During the "a little long" gap, the output will decay towards zero. When the next pulse comes in, the output won't change too much, and will continue to decay a bit through the "a little short" period. Then, when the early pulse comes in, that looks like a sudden increase in speed, so the output will immediately pop up to a higher value. It will always average out over a full cycle, unless your magnets are moving :) - Steve ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
