What is LabVIEW?
LabVIEW is a graphical programming language that uses icons instead of text lines to create applications. Unlike text-based programming languages, where instructions determine program execution, LabVIEW uses data flow programming, where the data flow determines execution.
In LabVIEW, you build a user interface using a set of tools and objects. The user interface is known as the front panel. Next, you add code using graphical representations of functions to control the objects on the front panel. The block diagram contains this code. In some way, the block diagram resembles a flow chart.
What is the use of virtual instrumentation?
You can use virtual instrumentation to create a complete and customized system for test, measurement, and industrial automation by combining different hardware and software components. If the system changes, you often can reuse the virtual instrument components without purchasing additional hardware or software
Using LabVIEW, you can
- create test and measurement
- Data acquisition
- Instrument control
- Data register
- Measurement analysis
- Report generation applications.
How computers control instruments?
Computers control the instruments by sending commands to the instruments through a bus, such as GPIB, PXI or RS-232. For example, you can send a command to the instrument to measure a signal and then send another command to send the resulting data about the bus to the computer.
LabVIEW programs are called virtual instruments (VIs). VIs contain three main components the front panel, the block diagram, and the icon and connector panel.The following examples shows a front panel.
You can build the front panel with controls and indicators, which are the interactive input and output terminals of the VI, respectively. The controls are knobs, buttons, dials and other input devices. The indicators are graphics, LEDs and other screens. The controls simulate instrument input devices and supply data to the VI block diagram. The indicators simulate the output devices of the instrument and show data that the block diagram acquires or generates
After building the front panel, add code using graphical representations of functions to control the objects on the front panel. Objects in the block diagram include terminals, subVIs, functions, constants, structures, and cables, which transfer data among other objects in the block diagram.
The following example shows a block diagram and its corresponding front panel
The following example shows a block diagram and its corresponding front panel. After you build a front panel and block diagram, build the icon and the connector pane so you can use it in another VI. AVI within another VI is called a subVI . A subVI corresponds to a subroutine in text-based programming languages.