What is the Difference Between the DAQmx Export Signal VI and the DAQmx Connect/Disconnect Terminals VIs?

Updated May 22, 2023

Reported In

Software

  • LabVIEW

Driver

  • NI-DAQmx

Issue Details

What is the difference between the DAQmx Export Signal VI (ExportSignal in the DAQmx API) and the DAQmx Connect/Disconnect Terminals VIs (ConnectTerms/DisconnectTerms in the DAQmx API)?

Solution

The DAQmx Export Signal VI uses task-based routing. With task-based routing, the connection is committed when the task is committed, and the route will stay reserved until the task is cleared. Refer to the LabVIEW help for the DAQmx Export Signal VI to find a list of the valid control signal values. 

The DAQmx Connect/Disconnect Terminals VIs use immediate routing. The immediate routing connections are committed immediately when the code reaches the DAQmx Connect Terminals VI. Because this connection is not contained within a task, it will stay connected through opening and closing of tasks. You must explicitly disconnect the route using the DAQmx Disconnect Terminals VI to remove the route. The DAQmx Connect/Disconnect Terminals VIs can establish a more permanent route between two terminals, providing more flexibility for routing options than the DAQmx Export Signal VI.

For more information on task-based routing and immediate routing, consult the Signal Routing section under Key NI-DAQmx Concepts in the NI-DAQmx LabVIEW help .