Hi,

I'm working on a new project that will be using 4 load cells to
measure the weight of a piece of machinery during operation.

I've seen weighing platforms that use a load cell on each mounting
foot - presumably they just average the four readings to get the
total weight eg. (A+B+C+D)/4 ?

Can I minimise the electronics by putting the outputs of the four
strain gauge bridges in parallel (maybe with some series resistors)
and then just use one bridge amplifier and one ADC input on my
micro? (Rather than 4 x bridge amps, 4 x ADC's)

Would this affect linearity much?  My dynamic range of weight is
very small, I'm looking to measure 0-20kg change (product) on top
of a constant 500kg or so (the machinery itself), and 0.1 or 0.2kg
resolution would be fine enough.

Also, what are your favourite bridge amplifier's for a job like this?

Hope these are simple questions to answer for people with
experience here, and interesting for the rest of us!

Thanks in advance, Brent.

Brent Brown
Electronic Design Solutions
16 English Street
Hamilton, New Zealand
Ph/fax: +64 7 849 0069
Mobile: 025 334 069
eMail:  brent.brown@clear.net.nz