VISA serial interface works only in design mode

[RavensFan]

Yes, the VISA Resource control.  The one that outputs a purple wire.

For the INI, I save it as a string such as "COM3".  You can wire a string into a local variable of the VISA control and it will coerce the name into the purple reference data type automatically.

Here's an example.  Though in this case I used Variant to Data to do convert to the correct data type.  It also shows how I triggered the event case to automatically open the com port.  Those error wires lead to the loop that includes the event structure.