If can be any comfort for you. You are not the first doing this kind of mistake;). Then I am working with with a unknown/new instrument. I have made it a habit to always make my test program so close up to data sheet a possible. If it specify bytes I send bytes, and if they are documented in hex I use that format. Later then I know the protocol basics I can change the format. I have wasted some hours by dumb errors. Like be 100 percent sure a string is set to hex display then it is not sigh!
Besideswhich, myopinionisthatExpressVIsCarthagemustbedestroyeddeleted (Sorry no Labview "brag list" so far)