Hello - I'm hoping someone could help point us in the right direction on this issue. We are using the INA12UA as an amplifier for a load cell bridge measurement circuit with two different load cells. We've gotten the circuit to perform well with one load cell, but are having issues getting the expected output with the other type.
The amplifier is being powered with 5V, which is also the excitation voltage for the load cell bridge. In one configuration, we are using a 20mV/V load cell and use an Rg = 1K for a gain of approximately 64. This configuration seems to work well. However, using the 1mV/V load cell with an Rg=60.4, the output of the amplifier doesn't seem to change regardless of the load on the load cell which will generate a differential voltage between 500µV and 5mV. It hovers right around 60mV.
My guess is that the amplifier offset voltage drowns out any signal the 1mV/V load cell, and this 60mV is the gain being applied to the offset voltage, but we don't have enough experience with this type of circuit to be sure of that. If that's the case, is there anything we can do to read this 1mV/V load cell? Would a different amplifier be required? Would there be an amplifier that could handle signals in the range previously mentioned and still be able to drive an output in the 3.3V/5V range?
