I'm reading from a variable-voltage load cell. The change in voltage is around 4 mV. It has four wires: Excitation ground, Excitation positive, Signal negative, and Signal positive. When applying 10 volts across Excitation ground and positive, the voltage across the Signal negative and positive is around 4.3VDC. I would like to use the Signal negative pin as an analog reference, then measure the voltage to Signal positive. On the documents (https://static.industruino.com/downloads/manuals/Industruino_INDIO1286_&_INDIO32u4_product_manual_December2016.pdf), I see AREF on the ribbon cable, but it doesn't appear to be available on the board. How do I use a "custom" analog reference?
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