ADLINK PCI-9810 - Manual (Page 55)

Operation Theory 43
The formula showing the relationship of the A/D data and the
analog value is:
Voltage = AD_data x (1/K) x (Gain)
Where Gain and K are constants.
For analog input range -1 V to 1 V, Gain=1
For analog input range -5 V to 5 V, Gain=5.
For PCI-9812, K=2047x16=32752
For PCI-9810, K=511x64=32704.