Thanks for the replies!
This application has been running for the last 18 hours now without issue, so it is confusing.
Currently I am using a "cheap" USB to RS232 converter for development. I wonder if that has to do with the port getting stuck like a comment mentioned above.
Does anyone have a recommendation on a reliable USB to RS232 converter?
To answer a comment above, what I meant by the port freeze/stuck is that it will not respond anymore. It doesn't seem to be timing out since I'm not seeing lags in the program. When write commands are sent nothing seems to be processing, and I won't be getting a feedback either. When I exit the application, it will process through a VISA Clear and VISA Close vi, and they both error out. I will have to unplug the USB adapter and re-plug it in to get the port to reset.
Also does anyone know of a program that can monitor a serial port and possibly diagnose when the port gets stuck?