Nodes are connected to one another using wires, e.g., two controls and an indicator can be wired to the addition function so that the indicator displays the sum of the two controls. Collectively controls, indicators, structures, and functions are referred to as nodes. The structures and functions are found on the Functions palette and can be placed on the back panel. The back panel also contains structures and functions which perform operations on controls and supply data to indicators. All of the objects placed on the front panel will appear on the back panel as terminals. The back panel, which is a block diagram, contains the graphical source code. Indicators are outputs: they indicate, or display, the results based on the inputs given to the VI. Controls are inputs: they allow a user to supply information to the VI. The front panel is built using controls and indicators. The last is used to represent the VI in the block diagrams of other, calling VIs. Each VI has three components: a block diagram, a front panel, and a connector pane. LabVIEW programs-subroutines are termed virtual instruments (VIs). LabVIEW integrates the creation of user interfaces (termed front panels) into the development cycle.
