Convert existing Labview program's comm protocol

[Justin_S]

I have an existing LabView program which communicates with an NI RS-485 serial card, but would like to change the communication protocol so the program communicates with a USB interface.  I'm expecting to use a RS-485 to USB converter module outside the PC so the device I'm communicating with doesn't need to change, but have greater portability since a laptop and not all PCs have a RS-485 PCI card.  I'm just trying to get an initial feel for the level of effort involved in accomplishing this task.  Any feedback would be appreciate.  Primarily of interest is knowing whether or not I would need to modify the LabView source code to accomplish this task, or can it be accomplished by some other means (i.e. changing some global settings on my PC).

[Dennis_Knutson]

Depending on how you wrote the program, there's the chance that you won't have to change a thing. Assuming you are using the VISA Read/Write functions, it should not matter whether the RS-485 is an internal card or a USB converter. The only thing that would change would be the com port name. If you have hard coded the VISA Resource Name with an alias like Com1, you can go into MAX and make the alias of the USB converter the same.