On Mon, 23 Aug 1999 19:57:35 +1200, you wrote:

>+AD4- I've been struggling with a way to do a low cost isolated A/D
> +ADwAJA-2/
>+AD4- channel) for a PIC 16C877.  I need a total of 4 isolated inputs at
>500V
>+AD4- of isolation with 8bits of resolution.  I've looked at a lot of
>+AD4- different possibilities, so far, a voltage to frequency converter
>coupled
>+AD4- through an optocoupler seems to be the most cost effective solution.
>
Does each input need isolating from the other ? If not how about a
12C671 on the hot side sending async serial data through an
optoisolator ?