RE: [CAD_CAM_EDM_DRO] Spindle Encoder resolution

Jon Elson wrote:

> Now, with a spindle encoder
> of 200 cycles/rev, that gives 800 (real, not pseudo) counts/revolution.

My only reason for the pseudo is that I understand the encoder output edges, since they come from 2
sensors and different detection directions, are not necessarily as uniform as one edge from one
sensor. So the accuracy of the encoder may be worse when this is tried (but then again, might not be
significantly worse).

> What I'm trying to point out here is that the resolution of the Z axis
> (stepper or servo/encoder) will be dominant most of the time, not the
> spindle encoder.

AHaa (if that's how to spell it). I now realise why the 400 may be sufficient. Thanks for the
insight I missed. By the time your argument starts to fail the tool is cutting significantly
sideways and other problems would seem to occur.

One situation where is might still be a problem is if the tool is a grinding wheel or milling
cutter, the spindle speed IS very slow, and sideways motion would be used, in for instance, cutting
a fast return mechanism spiral onto a rod. Even then, I suppose the spindle encoder could be on the
Z, and the controlled motor drive on the spindle.

Thanks again, Dennis