>> 4-20mA loop but all are now configured for a 1-5mA loop

I've used several versions of this circuit

http://www.piclist.com/techref/microchip/aout.htm

including for remote PT100 temperature sensors

Load at the PIC A/D pin is eg 250 ohms @ 0-20mA to convert
back to a 0-5V signal for digitising

Joe
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