Re: [CAD_CAM_EDM_DRO] Re: Encoders / Slides

Dave Fisher wrote:

>Hi All,
>
>We have a machine already fitted with 3 x 10 micron resolution glass slides
>that work with the DRO. We would like to convert this mill to CNC and wonder
>if we can utilise the slides instead of having to buy 3 rotary ?. The slide outputs
>seem to be 5 Volt TTL.
>

>I'm not sure what you mean by 3 x 10 micron resolution. If the glass
>

scale has stripes on a 12 uM pitch, that would give .000118" per quadrature
count. That is probably good for CNC motion control. I don't know where
the x 10 fits in here. The problem is any backlash between the drive motor
and the encoder will cause servo hunting. If you use good anti-backlash
ballscrews, it should work. it would be good to make sure you use a
servo amp with good controls for loop compensation, as there are a
number of places for resonances to develop in such a system.

Jon