I know that it is possible to convert a string to a VISA resource (see image below). However, in a program where you will have many sub-VI's that talk to the same resource, it is possible to pass only the string, and do the conversion inside the sub-VI's, or does the resource type include extra information (reference ID etc) and one has to pass the VISA resource all the time to the subVI's? I just want to add that I always perform a VISA open at the start of a program and a VISA close at the end even though it might not be needed in the newer versions of LabVIEW. Thanks!

I would not directly use the VISA resource name, instead use the opened VISA reference as shown below (I would not care about the coercion dot here)

You can pass the VISA resource as a string to the subVIs and convert it internally. As far as I have used VISA resources, they are forgiving if you use string and haven't come across a functional limitation of using string instead of a VISA resource data type. The advantage of using the VISA resource type is you can directly wire them to property nodes and access additional information from the VISA manager. Initializing VISA resources once and closing at the very end is the correct way to implement.

LabVIEW

VISA resource vs. string

Solved!

Excellent point. I have inherited code that stores a VISA resource as a string and feeds that to VISA Open with a coercion dot. After VISA Close, VI Session Monitor shows no sessions open. But a VISA Control for that resource still shows it as open.