Passing I/O Parameters Between LabVIEW VIs in TestStand

Updated Dec 1, 2023



  • TestStand
  • LabVIEW


  • IVI Compliance Package
  • NI-FieldPoint
  • NI-Motion
  • NI-DAQmx

I am trying to pass an I/O control and indicator from LabVIEW to TestStand. What type of variable would I use for this?

Use a LabVIEWIOControl variable type in TestStand for LabVIEW I/O controls such as VISA Resource Name, IVI Logical Name, FieldPoint IO Point, Motion Resource, DAQmx Task Name and DAQmx Channel Name.

To insert this variable:

  1. Go to the Variables pane and under the Locals section, right-click and select Insert Local»Types»LabVIEW»LabVIEWIOControl (replace Locals with Parameters if needed).
  2. Leave the SessionNumber set to 0, and enter the name of the device in the DeviceName property.
  3. Pass the created LabVIEWIOControl variable to the input I/O parameter of your LabVIEW VI.

Additional Information

LabVIEW I/O controls are represented as clusters with two elements, DeviceName and SessionNumber.

In a VI that takes an I/O reference as an input, use the DeviceName property to pass the name of the device and set the SessionNumber property to 0. The output I/O parameter, which you use if you plan to use the device in another VI, populates the SessionNumber property and allows you to use the SessionNumber property in other VIs. If the value of the SessionNumber property is not 0, LabVIEW ignores the DeviceName property.