RogerN wrote:
"Jim Stewart" wrote in message ...

RogerN wrote:
Just thought I'd share this in case anyone wants to mess with Arduino
scales
and the AD7730 chip, I can paste my Arduino code that will help get you
started. I couldn't find any functional code with my searches so I
started
with a program that wasn't working and got it going with major
modifications.

The AD7730 is an amazing chip. I used them for
a downhole tool years ago, to measure temperature
and pressure. A little pricy but worth all of
it if you're just doing a few devices.

As I get more familiar with this chip I hope I can get it to work well for
me. It seems to work pretty good now but I'm using internal calibrations
for zero and full scale when I power the chip up, this doesn't seem to give
the same readings twice so I have to recalibrate my scale every time I use
it. I'm planning to try it with power up defaults and see if it works
without running through the calibration routines every time it's reset. My
future plan is to use an LCD display and some buttons so the AD7730 can be
configured using a menu and the buttons. The chip does keep the parts down,
I have the AD7730, a few capacitors, and the clock crystal on the
breadboard.

We always did a recalibrate after a reset. Never
found a way around it. Another gotcha is changing
channels. Be aware that after changing channels,
you have to do several (the number escapes me now)
conversions to flush the delta-sigma pipeline before
you get an accurate reading on the new channel.

Keep us updated on your progress.