What kind of data acquisition card are you using? There should not be a problem with the wiring between the nodes you are working with, since Labview will automtically coerce the data type to the correct format. I suspect you have a DIMENSION conflict. Enable your context help, and then pause on the wire you are trying to connect. It should tell you exactly what the conflict is. Do you have an example of the VI you're working on?
Eric
Eric P. Nichols
P.O. Box 56235
North Pole, AK 99705