"If the control or indicator for which you want to get the index does not have a terminal on the block diagram, this property returns an error"
Your numerics inside of clusters, so they haven't terminals
The best option, as you now do, connect the wires directly to the clusters' terminal .
I'm not sure what I'm missing here. The VI won't run because of the error.
How will the control indexes be updated on the front panel if they are not wired up?
How do I tell the control index that the numeric's in the clusters are it's terminals, or can that be done?
Why are you trying to get indexes of numerics?
The DAQmx Read outputs are connected to the terminals of the clusters. The data is displayed. There is no need to record them also through indexes.
Remove everything that is painted yellow.
I ended up using a portion of the scribbled out code to control the BG colors of the indicators in the clusters on the front panel. Yes, control indexes were no longer needed because the data from the modules is going directly into the clusters.
Thanks for your help!