You should show your VI, preferably a snippet (https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000x2PkCAI&l=en-US ), so people can have a look. Usually these drivers come with some simple example VIs, did you try one of these? These examples show you how to use the driver VIs, like the Open and Close functions. It is not clear without more info what you mean about "channel list".
What is the interface/protocol you use? RS232? RS485? GPIB? Ethernet?...
