I'm designing a circuit to take two load cells as inputs, and make their sum. I'd like to know your opinion about the design.
Each cell is connected to one instrumentation amplifier (INA122P).
The supply will be a car battery, so I think there shouldn't be a lot of disturbance. Please consider that the output will be connected to an ADC, but the cable will be long, so I don't know if I have to take into account some more issues.
It's not written, but the regolator is the 7805, so everything will work at 5 V. For the summing part I found the AD8271 that seems interesting.
Any idea/correction/suggestion? It's one of my first designs and I don't know if I miss something important..
thank you all for your comments. Here is my updated schematic with your suggestions:
1.by connecting one output to the Vref of the second amplifier, I loose the adjustments (calibration) that I could do on the second load cell, don't I?
should I take into account some filtering for the supply or it's ok as it is?
why the ina122 is not a good amplifier? I could use it with the same configuration?