Remarks
Use the [SENSe:]VOLTage[:DC]:NULL:VALue command to set the null
value.
The CONFigure[:VOLTage][:DC] and MEASure[:VOLTage][:DC]?
commands turn off the null state.
A Factory Reset (*RST command) or an Instrument Preset
(SYSTem:PRESet command) returns the null state to off.
