The function niScope_ConfigureVertical() in the NI-SCOPE instrument driver has an input for setting the vertical offset parameter of the scope. However, the NI 5911 hardware does not support this feature and will always return an error to you if you use a value other than zero. The error message returned as of NI-SCOPE 1.6 is:
Error occurred at: niScope Configure Vertical.vi
Error Description: (Hex 0xBFFA0010) Invalid value.
Elaboration: Vertical Offset is invalid.
This feature is supported by the NI 5102 and NI 5112 High Speed Digitizers.