I've been having an issue where the circuit outputs two simultaneous signals on the oscilloscope, one that is the correct reading, and one that stays at 0 volts.
Here is a basic circuit schematic. The 100 ohm resister should mean the gain on the instrumentation amplifier is 501.
Here is an example oscilloscope output. The top bar, despite some noise, gives the correct output. The bottom bar stays at 0 volts.
The load cell is a strain-based wheatstone bridge, Omega Engineering LC302-25.
Why is this happening, and is it something I can fix?