labview programming environment and basic operations
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LabVIEW
• Laboratory Virtual Instrument Engineering Workbench.
• Development environment for the G ‘Graphical’language.
• Produced by National Instruments for all major operating systems.
• You can do anything with LabView that you can with C++ or any other scientific programming language
LabVIEW
LabVIEW• Originally developed for communication
with laboratory devices.• Communication Through
»GPIB»Serial RS-232 & RS-485»USB»VXI»PXI»Plug in Data Acquisition
Virtual Instrument
• Virtual Instrument is an instrument has the all main properties of a real one, but it is being “only” a computer program
Virtual Instrument• Virtual instrumentation also combines hardware and software with
industry-standard computer technologies to create user-defined instrumentation solutions.
Virtual InstrumentLabVIEW VIs contain three main components: the front panel, the block diagram, and the icon/connector pane.
Front Panel• The front panel is the user interface for the VI. • It contains the Front Panel toolbar and the Controls palette. • You build the front panel with controls and indicators.
Front Panel
Front Panel
IndicatorsControls
Front Panel Toolbar
Errors in the VI
To run the VI For objects alignment
The VI is runningFor objects spacing
For continuous run
VI is running continuously
To abort execution
Pause execution, continue by another click
Text settings
To order objects which to front and back
Block DiagramThe block diagram provides the area for the graphical code.
Block Diagram
For each Control or Indicatorin the front panel corresponding terminal in the block diagram generated automatically
Block Diagram Toolbar
Block Diagram ToolbarHighlight: To high light execution and see how the data flow
Step Into: To see the execution step by step and it enters the SUBVI and Loops
Step Over: To see the execution step by step by pressing it, SUBVI and Loops Considered one step, it does not enter to it.
Step Out: To exit the loop or SUBVI in one step and navigate to next node
Icon/Connector pane• You can use a VI as a subVI. • A subVI is a VI that is used inside another VI. • To be used as a subVI, a VI must have an icon and a connector pane. • The connector pane is a set of terminals that corresponds to the controlsand indicators of that VI.
Saving a VI• To save a VI, select File>>Save.• When you have saved your VI, you can select File>>Save Asto access the Save As dialog box below.
LabVIEW Palettes•The Front panel contains:
The Controls Palette
•The Block Diagram panel contains:
The Functions Palette
1- Controls Palette• To open the control palette from the front
panel
• Or click the mouse right button
1- Controls PaletteThe Controls palette contains the controls and indicators you use to create the front panel.
Some Controls
Some Controls
2- Functions Palette• To open the Functions palette from the block
diagram window
• Or click the mouse right button
2- Functions PaletteThe Functions palette contains the VIs and functions you useto build and design your program.
Some Functions
Some Functions
Some Functions
Some Functions
Some Functions
Some Functions
Some Functions
Some Functions
Some Functions
3- Tools Palettes• To open the Tools palette from the block
diagram window or front panel
3- Tools PalettesThe Tools palette is available on the front panel and the block diagram to operate, edit and modify objects.
Tools palette
Dataflow Programming
• Block diagram executes dependent on the flow of data; block diagram does NOT execute left to right
• Node executes when data is available to ALL input terminals
• Nodes supply data to all output terminals when done
Creating VIs
• Example 1: Converting ºC to ºF°F = (1.8 * °C) + 32
Control
Indicator
Creating VIs• Example 2: Add and Subtract two numbers
ControlsIndicators
Creating VIs• Example 3: Slope of a Line
Creating SubVIs
• After you build a VI, create its icon and connector pane, then you can use it in another VI as a subVI .
• Step #1: Create the IconRight-click on the icon in the front panel
Creating SubVIs• Step #2: Create the Connector
Creating SubVIs• Step #3: Select the terminals pattern
according to the number of inputs and outputs
Creating SubVIs• Step #4: Assign Terminals
Creating SubVIs• Step #5: Save the file. Like “Slope.vi”• Step #6: Insert the VI into a Top Level VI
LabVIEW Context Help window:
• This windows gives the basic information about the object that is in the front panel or block diagram
• This window appears just when you point to the object.
Context Help window
Context Help window• To activate the Context Help window
Context Help window
• Context Help window contains:
Context Help window Terminals
1- Required Terminals:The terminals that must be connected and it appear in a Bold font
Context Help window Terminals
2- Recommended Terminals:The terminals that are better to be connected and it appear in a plain font, or it will take the default values.
Context Help window Terminals
3- Optional Terminals:The terminals that are optional to beconnected and it appear in a dim font, or it will take the default values.
Context Help Three Keys
1- Hide Optional Terminals and Full Path:
Context Help Three Keys
2- Lock Context Help:
Context Help Three Keys
3- Detailed help:
Assignment #1:
Write a VI that calculate the roots of a second order equation.
AX^2 + BX + C = 0
Assume that the roots are real.
Run the VI with A=1, B=5 and C=6