Memory Considerations when Using Local Variables

When you create subVIs, you create a connector pane that describes how to pass data to and from the subVI. The connector pane does not make copies of data buffers from calling VIs.

Local variables make copies of data buffers. When you read from a local variable, you create a new buffer for the data from its associated control.

If you use local variables to transfer large amounts of data from one place on the block diagram to another, you generally use more memory and, consequently, have slower execution speed than if you transfer data using a wire.