All I can say is just "wow". I'm amazed that Dennis was able to figure out what you were doing wrong even before you posted your VIs. I never would have thought the newest of newbies would ever make such a mistake. I can only recommend you take some tutorials on LabVIEW.
You can use your VI #1. I guess you just never took a class or tutorial that showed you how to create a constant and wire it to a subVI to change the inputs into a subVI. If you right click on the connector to the bottom side of the Create Channel, the one call Excitation source, then choose Create Constant, now you will have a constant that you can change from the default of external to internal.
