Re: [CAD_CAM_EDM_DRO] Servo amplifier boards.

johndroc@... wrote:

> Jon,
>
> Thanks, for the info. I found out the crash problem the hard way!
> The
> X-Axis is now "stuck" (and the amplifier doesn't like it much at all),
> so
> I'll probably have to reverse the signal wires and let it "drift" the
> other
> way for a while. What does differential input mean? There is a
> selector on
> the amp for diff. input; does that mean it's not a standard ground?
> I'll get
> this thing fingered out yet...!

Differential input means that the input value is the difference between
two floating
signals, rather than between one signal and a common ground. The servo
amps
looked like a perfect place to use differential inputs, as the high
currents are bound
to cause voltage shifts on the ground reference. If you can select the
servo amp
for differential, then use the 'signal' wire as you are doing now, and
bring a ground
wire from the STG card to the '- signal' input on the amp (however it
might be
labeled).

Jon