I was thinking along the lines of using another PIC (like maybe 12C671)
powered from the motor supply making the motor measurements, but
electrically isolated from everything else, then sending a bit stream
through an optocoupler to the PIC with the EEPROM.  It's cheap (<$2 in 25's
from Digikey), tiny (8-pin), and has an 8-bit A/D.

> -----Original Message-----
> From: Andy Kunz [SMTP:support@MONTANADESIGN.COM]
> Sent: Thursday, October 28, 1999 12:15 PM
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      Re: [PIC] Measuring Analog Voltages w/o Sharing Grounds
>
> >If that isn't the case, pretty much everything I said is meaningless
> drivel
> >and just ignore it...
>
> But you said what I wanted to hear - don't take it all back!!!
>
> I think Dwayne interpreted me more correctly.  I'm looking to keep these
> other systems isolated from the Power system.  Not just because of noise,
> but because it's possible that they are connected inadvertently and I
> don't
> need to let magic smoke out of somebody else's equipment, let alone mine,
> by picking up "ground" in different places.
>
> What I need is some way to measure the Power parameters without being
> electrically connected, in a way of thinking.  I would opto-isolate if
> necessary, etc, but that gets into other problems (like real estate).
>
> Andy
>
> ==================================================================
>  Eternity is only a heartbeat away - are you ready?  Ask me how!
> ------------------------------------------------------------------
> andy@rc-hydros.com      http://www.rc-hydros.com     - Race Boats
> andy@montanadesign.com  http://www.montanadesign.com - Electronics
> ==================================================================