You might encounter this error when wiring VISA resource references or VI Server references. VI Server references include Application references, untyped VI references, strictly typed VI references, and LabVIEW Object references.
If you are wiring VISA refnums, this error means that you have wired two VISA sessions together whose classes do not match, or that the function to which you have wired the VISA session does not accept sessions of the given class.
To correct this error, change the VISA class of the signal input or output terminals to match. You can change the VISA session class of any front panel control or indicator by right-clicking it and selecting Select VISA Class from the shortcut menu. If both ends of the signal are connected to functions, you have to break the wire and choose a different function for either input or output.
If you are wiring a VI Server refnum, this error means that you have connected two different types of VI Server references together, or you have wired a VI Server reference to a function that does not accept the server class of the reference.
For example, in the following illustration, an application reference has been wired to a Call By Reference Node. However, Call By Reference Nodes accept only strictly typed VI references.
To correct this error, right-click the input reference and select Select VI Server Class from the shortcut menu. For this example, select Strictly Typed VIs from the shortcut menu to use any previously selected connector patterns or select Browse to select a connector pattern from a saved VI. When you resolve the class conflict, the wire appears solid.