Do Nested Loops in LabVIEW™ Execute in Parallel?

Issue Details

I have a For Loop nested in a While Loop (or a similar nested loop combination) that performs an operation, such as acquiring data or calculating a value, in the outer loop and a different operation in the inner loop.

When I run the VI, the code executes, but the operation in the outer loop executes only after the inner loop finishes all its iterations. How can I make both loops execute simultaneously? Is it expected behavior that the outer loop waits for the inner loop to complete?

Solution

This behavior is expected in LabVIEW. When a loop is nested inside another loop, the inner loop must complete its execution before the outer loop can proceed to its next iteration.

To execute both operations in parallel:

1. Remove the loop that must run independently from the nested structure.
2. Place the loops side by side on the block diagram instead of nesting them.
3. Implement a communication mechanism between the loops if data must be shared, such as queues, notifiers, or local variables, depending on the application requirements.

As a result, both loops can execute in parallel according to LabVIEW dataflow principles.

Additional Information

LabVIEW executes nested loops sequentially with respect to loop hierarchy. The outer loop cannot advance to its next iteration until the inner loop completes execution.