Hardware calibration is set at the factory and should never
need adjustment. The software should always be able to calibrate
to yield peak performance.
There are two potentiometers on the board. The potentiometer
closest to the power input connector is the common-mode rejection
adjustment. The other adjusts the reference voltage. Changing the
reference voltage has the effect of changing the gain.
If you wish to reset the common-mode adjustment, first
connect the + and - input pins of a channel to a ground on the
analog input connector. Zero the channel by using the offset
command. Now remove the connection to ground and connect both
input pins to the 5-volt reference on pin 8 of the analog input
connector. Adjust the common-mode potentiometer for a reading of
zero. Repeat for best results.
The A/D gain is set by connecting a known voltage to an analog
channel. Do a system calibration, then adjust the gain
potentiometer to obtain the desired reading. Repeat for best
results.
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