Experimental Physics and
Industrial Control System

Emmanuel Mayssat <[email protected]> · Wed, 14 Nov 2007 09:16:32 -0800

On Wed, 2007-11-14 at 11:59 +0200, Heinrich du Toit wrote:
> Hi there
> 
> We have an Multi-sample ion source of negative ions by Ceium sputtering 
> for AMS application.
> So I was thinking maybe RS485 protocol.

If you were thinking about differential communication over copper wire,
this wouldn't work. If you look at the specs of anything that can be
configured as differential (ADC, DAC, serial,...), you will read that
ground potential + max differential voltage as to be within a range.
With your 250V offset, you probably don't meet that specification.

Opto-coupling may be the only solution.

--
E

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System