Thanks everyone for your help. I think I incorporated all suggestions. The program is working as expected. My only complaint is that the 2up.vi has a slight delay compared to the HHF11A.vi when comparing the indicators on screen with the physical device's LCD readout. Is there anything that could be done to help performance? I thought of separate parallel loops for each device, but I've read that has issues with synchronicity.
I don't think I can loop just the read and the indicators in the HHF11A.vi and get it to work as a subvi in 2up.vi. Is there any way I can run the initialization, clear, and open only once but keep as much of the "driver" workings seperate from a larger VI?
