OK, it appears you got the idea.
Just couple things:
Serial Port Read.vi is blocking the current task until all bytes arrives (if you are using only while loops then the microcontroller does nothing for 31/1920 = 16 ms). You can use Timed Loops, or check for available bytes before reading.
Checksum should be checked for each packet (e.g. inside CF case).
Also you should think about:
-what's happening if 3DM doesn't respond?
-how to handle errors (for example, a single bit error might result into a NAck from 3DM, so all the incoming stream will be different)
-etc.
