Supress DLL Popups

[maluigario]

Thanks to everyone for their posts.  There was a lot of helpful and insightful material in here.  While the original question of being able to suppress popups came around as a "No" (and I have marked the most relevant answer as such to that original question), the thing that solved my specific problem here was to wire the VISA Resource handle into a pair of "VI Open" and "VI Close" blocks to verify that the device is connected and able to communicate:

If there is no error, then I know that a "Power_Supply" connected that LabVIEW can successfully communicate with.  Then I can just check for the other type of power supply first (the one that doesn't throw an unblockable popup), and save the Sorenson for last.  This should eliminate the chances that the popup appears while also being comprehensive in detecting which type is connected.

[rolfk]

If VISA Open alone will determine if there is a device or not also depends on the bus that is used. I believe this is a somewhat safe assumption for TCP/IP and GPIB devices only. For serial devices it means only that the local port could be accessed but not that there is a remote device connected. IT may be necessary to send a command like *IDN? to the device and try to read its response to determine that a device is actually connected for real.