VI Interop (G Dataflow)

Node Behavior When the Connector Pane of the Source VI Changes

If you make changes to the connector pane of the source VI after setting the path for the VI Interop node, you must clear the VI Path and reconfigure the VI Interop node to call the updated VI. Otherwise, the VI Interop node does not register the changes to the specified VI.

Automatic LabVIEW Version Selection

When you specify a path to a VI, this node automatically sets the LabVIEW version to the version in which the VI is saved if that version is available. Otherwise, the node automatically sets the LabVIEW version to the nearest LabVIEW version available on the local computer.

You can manually select a different available version of LabVIEW if you do not want to use the version that this node selects. However, this node may be unable to call the VI if you select a version that is older than the version in which the VI is saved.

Calling a VI in a Stand-Alone Application

To call a VI that is part of a stand-alone application, select VI Server application on the Item tab. You can connect to an application located on the same machine as LabVIEW NXG or on any machine whose name or IP address is known.

The stand-alone application must meet the following requirements:

• It must be an executable file.
• It must be built in LabVIEW 8.0 or later.
• It must include the VI you want to run.
• It must have a VI Server connection enabled.

Security Considerations Associated with VI Server

The VI Interop node uses VI server capabilities in the background to connect to a stand-alone application residing on the local machine or a remote machine. Opening a VI Server connection opens TCP/IP ports, which makes the system on which LabVIEW is installed vulnerable to local or network processes. For stand-alone applications, consider limiting the list of IP addresses which can interact with your application and restricting VI Server to invoking only the VIs which you want to make available to LabVIEW NXG.

Node Behavior When Calling a VI That Contains Type Definitions

If the VI you call contains instances of a type definition, this node neither recognizes the type definition nor converts the type definition to a G Type. If the VI uses a type definition as an input or output, this node uses the same data type as the type definition. However, this node does not connect type-defined inputs or outputs to G Types. You can use the Code Conversion Utility to create a G Type document that replicates type definitions in your project.

Unsupported LabVIEW Features and Behaviors

The VI Interop node fails to execute and generates an error when attempting to call a VI under the following conditions:

• The VI contains a channel input or output.
• The VI contains a reference input or output.
• The VI contains a class input or output.
• The VI contains a variant input or output and you wire a variant containing unsupported data to that input or output.
• The VI is an FPGA VI.
• The VI is part of an LLB or packed library.
• The LabVIEW version set on the VI Interop node is open when this node executes for the first time.

Calling Code from Previous Versions of LabVIEW

With the VI Interop node, you can use functionalities from previous versions of LabVIEW that do not currently exist in LabVIEW NXG.

If you cannot replicate the functionality using LabVIEW NXG features, consider moving the functionality into a subVI in the original version of LabVIEW and use the VI Interop node to call the subVI from your LabVIEW NXG application.

Note  

Opening more than one version of LabVIEW using multiple VI Interop nodes in one project can slow down the run-time performance in the development environment.

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported

Web Server: Not supported in VIs that run in a web application