Functions Overview

Functions are the essential operating elements of LabVIEW. Function icons on the Functions palette have pale yellow backgrounds and black foregrounds. Functions do not have front panels or block diagrams but do have connector panes. You cannot open or edit a function.

The Functions palette also includes the VIs that ship with LabVIEW. Use built-in VIs as subVIs in an application to reduce development time.

Adding Terminals to Functions

You can change the number of terminals for some functions. For example, to build an array with 10 elements, you must add 10 terminals to the Build Array function.

You can add terminals to functions by using the Positioning tool to drag the top or bottom borders of the function up or down, respectively. You also can use the Positioning tool to remove terminals from functions, but you cannot remove a terminal that is already wired. You must first delete the existing wire to remove the terminal.

You also can add or remove terminals by right-clicking one of the terminals of the function and selecting Add Input, Add Output, Remove Input, or Remove Output from the shortcut menu. Depending on the function, you can add terminals for inputs, outputs, or refnum controls. The Add Input and Add Output shortcut menu items add a terminal immediately after the terminal you right-clicked. The Remove Input and Remove Output shortcut menu items remove the terminal you right-clicked. If you use the shortcut menu items to remove a wired terminal, LabVIEW removes the terminal and disconnects the wire.

Built-in Categories

LabVIEW organizes the VIs and functions on the Functions palette using categories. When you install LabVIEW, built-in categories appear on the Functions palette. Some of the built-in categories do not contain objects by default. After you install certain modules, toolkits, and drivers, objects appear in the built-in categories that are empty by default.

LabVIEW also includes categories that are not built in. Categories that are not built in appear only after you install certain modules, toolkits, and drivers.

Click the Customize button on the Functions palette and select Change Visible Palettes from the shortcut menu to display all built-in categories on the Functions palette. You also can click the Change Visible Palettes link at the bottom of a pinned Functions palette to display the built-in categories. The following built-in categories are available on the Functions palette.

• Programming�Use the Programming VIs and functions as the basic building blocks for a VI.
• Measurement I/O�Use the Measurement I/O VIs and functions to interface with data acquisition devices. This palette displays the VIs and functions for the hardware drivers you install. Most common National Instruments hardware drivers ship with LabVIEW.
• Instrument I/O�Use the Instrument I/O VIs and functions to interface with GPIB, serial, modular, PXI, and other types of instruments. This palette displays installed instrument drivers such as GPIB, Serial, and so on.
• Vision and Motion�Use the Vision and Motion VIs and functions to interface with any of the NI Vision and Motion products. This palette displays the VIs and functions for the NI products you install, such as NI Vision, NI-Motion, and so on.
• Mathematics�Use the Mathematics VIs to perform many different kinds of mathematical analysis. You also can interface real-world measurements to the mathematical algorithms in order to obtain practical solutions.
• Signal Processing�Use the Signal Processing VIs to perform signal generation, digital filtering, data windowing, and spectrum analysis.
• Data Communication�Use the Data Communication VIs and functions to exchange data between applications.
• Connectivity�Use the Connectivity VIs and functions to work with .NET objects, ActiveX-enabled applications, input devices, register addresses, source control, and Windows registry keys.
• Control & Simulation�Use the Control & Simulation VIs and functions to design, analyze, simulate, and deploy dynamic system models. This palette contains VIs and functions for NI Control Design and Simulation products such as the Control Design and Simulation Module.
• Express�Use the Express VIs and functions to build common measurement tasks.
• Addons�Use the Addons category to locate palettes of some modules or toolkits that you have installed in LabVIEW.
• Favorites�Use the Favorites category to group together items on the Functions palette that you access frequently. You can add items to the Favorites category.
• User Libraries�Use the User Libraries category to add VIs to the Functions palette. By default, the User Libraries category does not contain any objects.