In article ,
"Lynn Coffelt" wrote:

"Bruce in Alaska" wrote in message
...
In article ,
"Lynn Coffelt" wrote:


I would look at some Optical Isolators to fix this problem. They are
cheap, easy to use, and provide 1000V Isolation....


Bruce in alaska
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Y'know, that's a real good idea. In fact, I think (woohoo) I remember
some equipment data ports already had optical isolators included in their
design. Newer Northstar stuff? Well, newer than the $9,995.00 Northstar 6000
anyway.

Old Chief Lynn



a lot of the original NEMA stuff used OI's as input devices just so they
wouldn't have to deal with Ground Loops on the data Paths. It is very
easy to drive the LED side of an OI with a few milliamps at 3 volts from
a considerable run of wire. Since it is digital, you just need enough
to cause a transition in the OI's receiver to cause data to flow. It
also makes driving parallel receivers, easy, by just building the driver
side with enough power to drive multiple LED's in parallel.

Bruce in alaska
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add a 2 before @