Re: Encoders

One thing you might want to do is also to tie a 10K resistor from 5
volts to the signal lines -- the 5 volts might only be powering the
light source, and might not be biasing the signal. If this turns out
to be the case, you'll need a pullup to see the signal swing.

It's also possible that the encoder is designed to use a sense
resistor (looking like a "pull down" to ground) -- but if that's the
case, your meter should read +5/Ground signals okay.

Joseph

--- In CAD_CAM_EDM_DRO@y..., Jon Elson <elson@p...> wrote:
> Ian Wright wrote:
>
> > Thanks Jon,
> >
> > Am I right in thinking then, that the quadrature output is only
on 2 wires,
> > probably in this case the brown and the white and that the
voltage on them
> > will swing above and below some central point to indicate the
four states.
> > I'm having difficulty visualising exactly where I should be
monitoring the
> > signals. As all the reds are connected together (I can see this
as tracks on
> > the pc-board) and the blacks also appear to be electrically
connected, that
> > only leaves brown, white and green, each of which has one of the
reds
> > adjacent to it. So, if I put 5volts across the red and black, do
I monitor
> > the voltage between say, brown and black or brown and red, or
perhaps brown
> > and green?
>
> Yes, if red is +5, and black is gnd, then monitor with the - lead
of the meter
> to black, and the + lead to the white, brown or green.
>
> Jon