Offset (V)
Specifies the location of the center of the range that you specify with Range (V). Express the value with respect to ground. For example, to acquire a sine wave that spans from -5.0 to 5.0 volts, set the value to 0. For a sine wave that spans from 0.0 to 10.0 volts, set the value to 5.0 and set Range (V) to 10.0.
Refer to the NI High-Speed Digitizers Help for a list of vertical offsets supported by the digitizer.