I'm trying to find a way to convert a bipolar signal from a load cell (Futek) to an input for a differential ADC on a TIVA microcontroller(TI TM4C123GH6PM). The load cell's amplifier outputs a bipolar (-2.67 V to 2.67 V) for a 500 lb range in tension and compression.
This setup uses decoupling capacitors (0.47 μF) to eliminate high frequency noise within the system. The noise is extremely low and I get very accurate readings, but the problem is that the GNDs of the microcontroller and float without reference to each other. I tried to do it this way so that microcontroller would never see a negative voltage, but treat the amplifier GND as a data input.
The problem is that now because I've dereferenced the GNDs of the two systems, there is no way to make sure that the two GNDs don't float away. I recognize that there needs to be another way to use a bipolar signal for a differential input, can someone help me?