Labview programming environment

Graphical environment

Functions palette

The Functions palette (see [link] ) provides various function VIs or blocks to build a system. View this palette by right-clicking on an open area of a block diagram. Note that this palette can be displayed only in a block diagram.

Controls palette

The Controls palette (see [link] ) features front panel controls and indicators. View this palette by right-clicking on an open area of a front panel. Note that this palette can be displayed only in a front panel.

Tools palette

The Tools palette offers various mouse cursor operation modes for building or debugging a VI. The Tools palette and the frequently used tools are shown in [link] .

Each tool is used for a specific task. For example, use the wiring tool to wire objects in a block diagram. If one enables the automatic tool selection mode by clicking on the Au tomatic T ool S election button, LabVIEW selects the best matching tool based on a current cursor position.

Building a front panel

In general, one constructs a VI by going back and forth between a front panel and block diagram, placing inputs/outputs on the front panel and building blocks on the block diagram.

Controls

Controls make up the inputs to a VI. Controls grouped in the Numeric Controls palette (Controls → Express → Num Ctrls) are used for numerical inputs, controls grouped in the Buttons&Switches palette (Controls → Express → Buttons) are used for Boolean inputs, and controls grouped in the Text Controls palette (Controls → Express → Text Ctrls) are used for text and enumeration inputs. These control options are displayed in [link] .

Indicators

Indicators make up the outputs of a VI. Indicators grouped in the Numeric Indicators palette (Controls → Express → Numeric Inds) are used for numerical outputs, indicators grouped in the LEDs palette (Controls → Express → LEDs) are used for Boolean outputs, indicators grouped in the Text Indicators palette (Controls → Express → Text Inds) are used for text outputs, and indicators grouped in the Graph Indicators palette (Controls → Express → Graph Indicators) are used for graphical outputs. These indicator options are displayed in [link] .

Align, distribute and resize objects

The menu items on the front panel toolbar (see [link] ) provide options to align and orderly distribute objects on the front panel. Normally, after one places controls and indicators on a front panel, these options can be used to tidy up their appearance.

Building a block diagram

Express vi and function

Express VIs denote higher-level VIs configured to incorporate lower-level VIs or functions. These VIs are displayed as expandable nodes with a blue background. Placing an Express VI in a block diagram opens a configuration dialog window to adjust the Express VI parameters. As a result, Express VIs demand less wiring. The configuration window can be opened by double-clicking on its Express VI.

Basic operations such as addition or subtraction are represented by functions. [link] shows three examples corresponding to three block diagram objects (VI, Express VI and function).