The reason I want to use a V-F convertor for an amp-hour meter is
- very simple, can use the lowest cost PIC
- no need to come up with a fast sampling scheme (A/D convertor may not
keep up)
- more resolution, bigger dynamic range - just count the pulses
- overall should prove to be more accurate since the voltage coming from
the shunt will be continuously monitored.
- easier to deal with RF noise coming from a DC-AC inverter also connected to
the batteries.
- pretty foolproof

Plus I have found some V-F ic's with built in amplification, 0.1% linearity,
80dB dynamic range.

BTW, since I'm only going to see 0 to 50mV signal, does the OP291 have a
very low
input voltage offsett and thermal drift?

Dave

>Why do you want to use V-F convertor ? Use PIC with ADC! I suppose that 8
>bit its enough (to use C71/C74), or use PIC14000 with it "up_to_16_bit".
> Of course, you can use OP Amp to amplify your 50 mV to 5V ADC input.
> I reccomend Analog Device's OP291 - Micropower, Single Supply,
>Rail-to-Rail Input & Output.
>