So I am trying to create a VI to control several pieces of equipment for an automated test set, and I current have it split into two different tabs, one for running the test and one for exporting the data. On the tab to run the test I have a start button that is supposed to start the testing process, but the button does not seem to be responding to clicks (even a Boolean indicator won't respond). Any help is appreciated, and the VI in question is attached.
Follow the path of the notification reference wire.
Your loops are running in parallel, bu tin series. Your notification wire runs out of the lower loop and into the upper loop near the lower right corner. That means your upper loop won't start until the lower loop has finished.
Unfortunately, I don't have a 10-foot-wide monitor to allow me to look at your Block Diagram. Do you know about sub-VIs? This lets you "hide" large block diagrams inside a 32x32 pixel square, saving a lot of Block Diagram Real Estate. Good LabVIEW Style keeps everything in your VI within a single (laptop) screen, say 1280 x 1024 pixels.
It is the rare VI that requires Tab Panels, and they are usually ones where there is a real (or, more often, only "perceived") need for extra Controls or Indicators. You've shown an almost blank Front Panel -- you almost certainly do not need a Tab Control, and I was unable to study your impossibly-large Block Diagram sufficiently to figure out a compelling reason (from your code) for one.
It is generally a better idea to Start Simple and Make It More Complex when Necessary than to put all the Bells and Whistles in at the beginning, "just because I might need to tweak this parameter". I've seen some extremely messy and difficult-to-debug Block Diagrams arise this way.