Re: [CAD_CAM_EDM_DRO] Re: Treadmill motors as Servos

Hi John,

> http://www.usdigital.com/products/rotary-kit-encoders.shtml
>
> Is there any advantage to using these over the others?
>

If they do one that fits the shaft on your motors it will save a bit of
hassle. Otherwise it doesn't make a lot of difference. Depending on
gearing you probably want somewhere between 200 - 400 CPR. Increasing
the CPR increases the positioning accuracy but reduces your maximum
speed. Ideally you want to be using close to the maximum available pulse
rate when moving at rapid speed. Remember you effectively get 4 steps
per encoder line so a 200 CPR encoder is 800 steps/rev.

> What about the gearing reduction, How did you do it?
> Timing belts?
>

5mm pitch, 15mm wide HTD timing belts. I used them because the spacing
between the pulleys worked out right with the reduction ratio I wanted.
Theoretically HTD have slightly more backlash than trapezoidal
'classical' timing belts but it is so small that it makes no real
difference.

> I don't want to push my luck with the questions, though, I'm trying
> to do it in the open for anyone else who may be follwing along.
>

No problem. :-)

Les