Re: doubling resolution strategy # 2

--- In CAD_CAM_EDM_DRO@y..., Doug Fortune <pentam@h...> wrote:
<snip>
>
> --- Use two encoders instead of one! ---
>
> This works for both linear encoders and rotary encoders giving out
> quadrature signals.

Hey that's a pretty cool idea!

I'm thinking this equates to a sort of 'microstepping' - only it
involves the feedback half instead of the drive half of the system.
Much like microstepping - I bet your final relation between actual
position and sensed position will form some sort of mostliy
straigt yet slightly wavy line - with exact agreement between the two
measurements only at certain periodic locations...

In the world of electronics - if you try to construct a 16 bit analog
to digital converter using two 8-bit converters - you run into
troubles involving the absolute precision of the two units. The
'noise' or error within the 8-bit units limits how far you can push
this trick. I suspect a similar effect would come into play when
using two encoders?

Let us know how it works out!

-Bill