>That's why I asked for practical schematics, specially of the input
>amplifier stage (I'm very bad at analog electronics.....), I couldn't find
>anything up to now (although I have some broken down PCB's (lightning !!!),
>so perhaps I'll do some "reverse engineering" on them to get an idea).

I like the circuit descriptions in the *excellent* Linear Technology
Application Handbooks.  The one that's most applicable is App Note #43,
"Bridge Circuits: Marrying Gain and Balance".  It's a Jim Williams app
note--'nuff said.  (I'm really fond of the common-mode surpression circuit;
it works well with a single ended ADC.)

For the digital side of things, I've been reading the Crystal Semiconductor
Industrial Data Acquisition book.  A lot of it is geared toward their
converters, but there are some good suggestions about tempco, trimming, AC
excitation, etc.

The LT notes are on their web site (www.linear-tech.com, I think).  Don't
know about the Crystal site.

If you find any other good reference material on load cells, be sure and
let me know!


later,
newell