unterhaus, I hooked up the oscope to the glass scale and was able to count the transitions on the A and B outputs when I move the Z axis. I did this several times but the results didn't seem to make sense. For instance, I'd move the Z axis appr 0.01102 inches and I'd get 28 transitions. A real head scratcher! Then for kicks and gigles I changed the CNC controls output to metric and... for 28 transitions the Z axis moved .28mm Ahhh that looks right.
So correct me if I'm wrong here. This glass scale looks to be a metric one. Would the resolution be 0.0001 or 0.0002 or 0.00005? or something else?
So that means for every inch of movement, the scales produce 2540 pulses (transitions on both A and B channels in quadrature) (this sounds very close to your original example). So if my ball screw is 5tpi (5 turns per inch) then I need a rotary encoder which will provide 2540/5=508 ppr(pulses per revolution)? I found one at
http://www.renco.com/106022.htm.
Does this sound right? Thanks, Michael