USB COM Port re-detection

[BHeadley]

I am currently using LabVIEW 7.1.1 to test a series of UUTs.  The UUTs contain a FTDI FT232R chip to convert a USB bus into a serial COM port.  I am using VISA mapping to connect to the COM port, along with a modified version of the FTDI driver to 'lock' the COM port locations on the test PC (preventing Windows XP from adding a new COM port for each new UUT tested).  So far, this part works fine.

After each test, I need to disconnect the first UUT then connect the next UUT.  The resource is found and mapped into the appropriate COM port location.  Unfortunately, when I re-run the test, the error message "-1073807194: VISA:  (Hex 0xBFFF00A6) The connection for the given session has been lost.".  The only way I have been able to continue testing is to exit and restart LabVIEW.  This test needs to be made fully automatic for production line purposes.

Is there a way in LabVIEW to re-acquire the VISA resources without having to exit and restart?  I recall a similiar problem with VXI chassis and running RESMAN to re-connect, but I don't know of such an animal for local PC resources.

Any help would be appreciated.  Thanks!

Bruce C. Headley

Balboa Instruments Inc

[Stephanie B]

Hi Bruce,

I would take a look at this KnowledgeBase which tells you how to do that programmatically and has sample code to do it too. You could have a button click event structure that when you click it, the program rescans and finds the resources. Let me know if you need any more information/detail! Thanks!

Stephanie