Dave Celsnak wrote:
.....
> Not sure what a load cell is....
.....

A load cell is a piece of steel with strain gauges in wheatstone-bridge
configuration in it, normally used for weighting purposes....

As the steel (and the strain gauges glued on it) deforms, the resistance
values of the bridge change, and there develops an output voltage between
two of the legs of the bridge, normally a very small voltage (in the order
of some mV), not so easy to measure and process in an industrial
environment with lots of noise, induction on cables, sometimes very high
temperature fluctuations, and the like. Also the input voltage to the
bridge must be held very constant, or there must be some means to measure
that voltage too and compensate (software !!!) for fluctuations in it I
think.......

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).

Albert Smulders
InSAD - Encarnacion, Paraguay
insad@itacom.com.py