LabVIEW and G Graphical Programming Language By: Ramtin Raji Kermani

What is LabVIEW? LabVIEW (Laboratory of Virtual Instrument Engineering Workbench) is a development environment based on graphical programming.

What is LabVIEW? LabVIEW relies on graphical symbols rather than textual language to describe programming actions The principle of dataflow, in which functions execute only after receiving the necessary data, governs execution in a straightforward manner.

LabVIEW features Product of National Instruments (NI) Software for Virtual Instrumentation Data Acquisition (DAQ) Graphical Programming Data Storage and Analysis for wide Range of applications

LabVIEW features LabVIEW programs are called: Virtual Instruments (VIs) because their appearence and operation imitate actual instruments. However, they are analogous to main programs, functions and subroutines from popular language like C, Fortran, Pascal, …

Virtual Instruments 1- The front panel: an interactive user interface of a VI, so named because it can simulates the front panel of a physical instrument. 2- The block (or wiring) diagram: It is the VIs source code, constructed in LabVIEWs graphical programming language, G. It is the actual executable program. Subroutine in the block diagram of VI. 3- Icon/connector

VIs Front Panel User Interface (UI) Controls = Inputs Indicators = Outputs Block Diagram Graphical Code Data travels on wires from controls through functions to indicators Blocks execute by Dataflow

Front Panel

a A combination of controls and indicators. Controls = Inputs from the user = Source Terminals Indicators = Outputs to the user = Destinations

Block Diagram

Terminals When you place a control (or indicator) on the FRONT PANEL LabVIEW automatically creates a corresponding control (or indicator) terminal on the BLOCK DIAGRAM

Control or Indicator Terminal? Control terminals have thick borders Indicator terminals have thin borders

Nodes Node is just a fancy word for a program execution element – Nodes are analogous to statements, operators, functions and subroutines in standard programming language: The add and subtract functions represent one type of node. A structure is an other type of node. Structures can execute code repeatedly or conditionally, similar to loops and case statements in traditional programming languages. LabVIEW also has special nodes, called formula nodes, which are useful for evaluating mathematical formulas or expressions.

Control or Indicator Terminal?

Data Types Each wire has different style or color, depending on the data type that flows through the wire: Scalar1D array2D arrayColor Floating-point number orange Integer number blue Booleangreen Stringpink

Type Checking If you connect more than one source or no source at all to a wire, LabVIEW DISAGREES with what youre doing, and the wire will appear broken

ACTION ! Let get into Action …