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VISA resources have a variety of properties, or attributes, with values you can read or set. You can use the Property Node to read or set the values of VISA properties.

After you place a Property Node on the block diagram, wire a VISA Session to the reference input of the Property Node. After you wire a session to the reference input of the Property Node, LabVIEW sets the VISA Class to the class associated with that session.

To optionally change the VISA class, right-click the Property Node and select Select Class»VISA»I/O Session from the shortcut menu. The default is Instr class, which encompasses all VISA properties for instruments. The other classes limit the properties displayed in the shortcut menu to those related to the selected class. In general, choosing a more specific instrument class is optional. Notice that for some classes, for example, Backplane and BoardInterface, properties and methods do not appear in the Instr class because there is no logical overlap. Therefore, for classes such as these, choosing the appropriate class is mandatory.

There are two basic types of VISA properties: global properties and local properties. Global properties are specific to a resource, and local properties are specific to a session. A global property has the same value for all the sessions that are open to a specific resource. A local property can have a different value for each session to a specific resource.