Analog to digital conversion
The AD7798 is a differential ADC.
It has a negative input and a positive input. When configured for bipolar operation:


When the voltage between in+ and in- is positive (in+ > in-) at full
scale the output will be all one.
When the voltage between in+ and in- is 0 (in+ == in-) the output
will be 1000...0000.
And When the voltage between in+ and in- is negative (in+ &lt; in-) at
full scale the output will be all zero.