How can a Labview VI be run as a background task through an ActiveX call ? (without keeping ActiveX busy)

Question

I would like to execute a Labview VI through ActiveX in Matlab.

I use the following commands:

e=actxserver(\'LabVIEW.Application\');
vipath=\'C:\\DATA\\L         


        

Answer 1

You can either:

• Launch LabVIEW.exe as a process, specifying VI as argument (search help for this). There is for sure a way to tell Matlab to not wait for end of process execution
• Run the VI dynamically, using VI server, inside a launcher VI, and have Matlab call the launcher VI. The latter will return immediately after calling your VI, and Matlab will not wait for your main VI to end.

Answer 2

I finally found the answer (thanks to smercurio_fc on the NI forum):

To run the VI in the background (without waiting until done):
vi.Run(1);

To run it and wait until its execution is complete:
vi.Run(0);
or
vi.Run;

In the background execution mode with vi.Run(1), execution can be interrupted with vi.Abort. During execution, input and output values can be changed with vi.SetControlValue and vi.GetControlValue.
For instance, to get the value of a numerical control 'z' during execution:
vi.GetControlValue('z')