I/O Controls - LabVIEW VI Call Parameters

I/O Controls

Some of the LabVIEW I/O controls are represented as clusters with two elements, DeviceName and SessionNumber. You can specify either a device name or a session number. The session number will always be used if it is not zero. The session number can be used in other development environments, such as LabWindows/CVI, as long as they are in the same process. You can use the TestStand data type, LabVIEWIOControl, to create variables for I/O controls.

Note Do not modify the value of the SessionNumber property of the LabVIEWIOControl data type yourself. The value of the SessionNumber property refers to an internal session for the device the DeviceName property specifies. Always set the value of the SessionNumber property to 0 initially, and use TestStand to populate the value of the SessionNumber property at run time if the property is an output parameter. 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 you can then use the SessionNumber property in other VIs. If the value of the SessionNumber property is not 0 , LabVIEW ignores the DeviceName property.

The following I/O control references are represented this way:

  • VISA
  • IVI
  • FieldPoint
  • Motion
  • DAQmx Task Name
  • DAQmx Channel Name

See Also

LabVIEW Data Types in TestStand

Mapping Parameters