Hello,
Currently there is no support for GPIB under VB .NET. You can however use Measurement Studio. The following link answers your question:
http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=313&HOID=506500000008000000556E0000&UCATEGORY_0=_26_%24_13_&UCATEGORY_S=0
Hope this helps.
Anu Saha
Anu Saha
Academic Product Marketing Engineer
National Instruments