Well, the scale originally only used 3V, so I figured why bump it to 5V if it isn't necessary? I put it to 5V just to see if it improved.
I knocked the Rg up to 88 ohms and it seemed to lower the no load voltage from 3.02V to 0.88V. I noticed the circuit is much more sensitive to interference as well. If i put my hand near the scale or IC it will change the Vo by lowering it (seems to be the case for both 22ohm and 88 ohm, but stronger at 88 ohm).
After the changes, there seems to be no improvement with the range. The Vo still drops to 0.07V (lowest it goes) at around 500g weight applied.
I wired up the INA125P just as the datasheet shows in the pic attached. I used the 2.5V ref pin 14 into 4 as shown.
Even with a simple INA128 I had the same results as this. Is it the load cell? It has the E+ E- S+ and S- outputs like any other.
