System Exec.vi Standard Input and Standard Output. Helps

[MQI]

Hi, I'm using the system exec.vi to call out an executable VI that has one input and one output.  How do I map the executable VI input and output to the system exec.vi standard input and standard output so that I can save the data log.  Thanks

BC

[DuffmanSays]

Hello BC,

I want to be sure that I understand you correctly: you have created a LabVIEW application and you are calling it from a command line through the system exec VI. You would like to pass it arguments and receive an output from this VI in the command shell?

If this is the case, I would suggest you take a look at this forum thread that discusses this type of application. Essentially, there is an application-class property node named "Command line arguments." This allows you to easily input data to your executable. As you will see in the linked forum post, the output can be a bit more tricky. Essentially you will be making calls to Windows DLLs to output the text of your choice. Please post back if this is what you were looking for or if we can help further! Thanks,

Mike D.
National Instruments
Applications Engineer

[MQI]

Hi, Mike.  Thank you for your response.  Yes, I build an executable VI just to try out the system exec.vi function.  The actual work I am doing right now is to call the Blue Soleil software (IVT) for pairing usb bluetooth dongle (DBT-120 from D-link) with a bluetooth enabled modem (BT56R from Billionton).  I can use the system exec.vi to open it, but that all I can do for now.  I like to automate sending the command to and then retrieve data output from Labview.  Thanks for your help.

BC

[DuffmanSays]

BC,

It was my pleasure to be of assistance. The system exec VI essentially behaves exactly like the command line. You might want to try calling the Blue Soleil software directly from the command line to see what options you have for parameters and returns. Please post back if we can help. Thanks,

Mike D.

[MQI]

Hi, Mike.  I can call the Blue Soleil software to open, but not sure how to insert the command into the standard input and have it return data at the standard output from Labview.  Do you have any example about the System Exec.vi.  That will help since I never use it before.

BC

[Dennis_Knutson]

I have no idea what Blue Soleil is but what an exe programs accept as inputs and how it outputs results is dependent on how the program was written. Do you happen to know that the program accepts command line arguments? If so, have you tried it from the window? Has the vendor provided any kind of information? A lot of windows programs do not support standard input and standard output. Many windows programs have an ActiveX automation interface.

[MQI]

  Hi, Mark.  Thanks for your response.  This is the website http://www.ivtcorporation.com that has the software.  It does provide some window API functions.  If I can' t use the system exec, then I will have to try window API method. 

BC