Do I need the the shield

[Natalie]

Hi all,

I have an SCXI-1303 terminal block plugged in to an SCXI-1102 module
that I'm wiring up for just straight voltage inputs, I'm using
shielded pair wiring for each channel, my question is do I need to
connect the shield to the Earth Ground Solder Lug from each of the
cables?

If this is the case do I also connect the other end of the shield to
the instrument I am measuring, or just one or the other?

Thanks for your input

Natalie

[Ben]

"Noise Reduction Techniques in Electronic Systems" by Ott is an excellent reference to answer this question.

Without getting into an extended answer let me suggest you try each configuration (with everything running) and see where do you get the best results.

The complete answer involves the length of the wire, the environment, grounding, expected signal characteristics....

Ben

[David Huff]

natwilkie@hotmail.com (Natalie) wrote in message news:...
> Hi all,
>
> I have an SCXI-1303 terminal block plugged in to an SCXI-1102 module
> that I'm wiring up for just straight voltage inputs, I'm using
> shielded pair wiring for each channel, my question is do I need to
> connect the shield to the Earth Ground Solder Lug from each of the
> cables?
>
> If this is the case do I also connect the other end of the shield to
> the instrument I am measuring, or just one or the other?
>
> Thanks for your input
>
> Natalie

You should connect the shield to the ground in the terminal block, but
not to the ground on the instrument, because connecting both grounds
to the shield might cause a ground loop.
Check out t
he following weblink at NI, it has a great introduction to
proper and improper wiring techniques.
<>
note that the entire link is enclosed in brackets<>

[Natalie]

Thank you to Ben & David for your inputs, most helpful.

Natalie




dhlabview@yahoo.com (David Huff) wrote in message news:...
> natwilkie@hotmail.com (Natalie) wrote in message news:...
> > Hi all,
> >
> > I have an SCXI-1303 terminal block plugged in to an SCXI-1102 module
> > that I'm wiring up for just straight voltage inputs, I'm using
> > shielded pair wiring for each channel, my question is do I need to
> > connect the shield to the Earth Ground Solder Lug from each of the
> > cables?
> >
> > If this is the case do I also connect the other end of the shield to
> > the instrument I am measuring, or just one or the other?
> >
> > Thanks for your input
>
>
> > Natalie
>
> You should connect the shield to the ground in the terminal block, but
> not to the ground on the instrument, because connecting both grounds
> to the shield might cause a ground loop.
> Check out the following weblink at NI, it has a great introduction to
> proper and improper wiring techniques.
> <>
> note that the entire link is enclosed in brackets<>