You can build the front panel with controls and indicators, which are the interactive input and output terminals of the VI, respectively. Controls are knobs, push buttons,dials and other input devices. Indicators are graphs, LEDs and other displays. Controls simulate instrument input devices and supply data to the block diagram of the VI. Indicators simulate instrument output devices and display data the block diagram acquires or generates.
Every control or indicator has a data type associated with it. They are numeric data type, Boolean data type and string data type as shown in Figure 2.11. The numeric data type shown in Figure 2.11(a) can be of various types such as integer or real. The two most commonly used numeric objects are the numeric control and the numeric indicator. The Boolean data type represents data that only has two parts, such as TRUE and FALSE or ON and OFF as in Figure 2.11(b). Use Boolean controls and indicators to enter and display Boolean (True or False) values. Boolean objects simulate switches, push buttons, and LEDs. Figure 2.11(c) shows the string data type which is a sequence of ASCII characters. Use string controls to receive text from the user such as a password or user name and indicators to display text to the user.
To keep an object proportional to its original size as you resize it, press the key while you drag the resizing handles or circles. To resize an object as you place it on the front panel, press the key while you click to place the object and drag the resizing handles or circles.