Your main vi just calls the subvi. The main serves no purpose. Just make the subvi the main vi. Get rid of all those local variables, none of them are needed. By putting the array indicator inside the loop, you will see an update every loop iteration.
If you have to call this from a main, then do this. In the main, create an identical indicator. Create a reference to that indicator. In the subvi, create a similar reference type. Pass the main reference to the subvi reference. In the subvi, create a value property node for the reference. Inside the loop, write the output to the value node. Everytime the loop executes, the value node will be updated and the main will display it because it is passed by reference. What happens is that because of the reference, the main indicator is sharing the same memory space as the subvi value node. So a change in one is seen in the other.
Another way to get the info from the subvi to main is to open a reference to the subvi in the main block diagram. Use property nodes to get the subvi front panel controls. Search by lablel to get the indicator you are wanting to display. Use a value property node to obtain the value and update your main indicator. I have attached an example.
