2010 Lab View Course Students

8/6/2019 2010 Lab View Course Students

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Getting started First Steps Programming Examples and Tasks

Labview Introduction in 3 hours

Volkmar Zabel

Maik BrehmDaniel Arnold

Institute of Structural Mechanics

Bauhaus University Weimar

Weimar, Germany

2010

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Outline

1 Getting started

2 First Steps

3 Introduction to LabVIEW Programming

4 Examples and Tasks



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Start LabVIEWstart from terminal with:

user@computer > /parrot/apps/natinst/LabVIEW-2009/labview



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Virtual instruments (VIs)LabVIEW programs are called virtual instruments (VIs),

containing 2 Windows: Front Panel and Block DiagramFront Panel = Front End

User Interface

Controls = inputsIndicators = outputs

Block Diagram = Back End

Graphical code

Data flow trough wiresfrom controls over functions toindicators

Blocks executes by data flowZabel/Brehm/Arnold 2010 4 / 47 ,


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Controls Palette

Controls Palette

Use the Controls palette to place controls and indicators on the frontpanel. You can display the Controls palette by right-clicking an open areaon the front panel.



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Functions Palette

Functions Palette

The Functions palette is available only on the block diagram. You candisplay the Functions palette by right-clicking an open area on the blockdiagram.


G i d Fi S P i E l d T k


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Status Toolbar

Status Toolbar Buttons

Run button Run the VI once.Countinuous Run button Run the VI until you abort it.

Abort button Stop the VI immediately.

Additional Buttons on the Diagram ToolbarExecution highlight button

Retain wire value button

Step function button


G tti t t d Fi t St P i E l d T k


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Data Types

LabVIEW uses many common data types

Boolean, numeric, strings, clusters, . . .

The color and symbol of each terminal indicate the data type of thecontrol or indicator. Control terminals have a thicker border than indicatorterminals. Also, arrows appear on front panel terminals to indicate whetherthe terminal is a control or an indicator. An arrow appears on the right ifthe terminal is a control and on the left if the terminal is an indicator.




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Data Flow

LabVIEW Data Flow

Block diagram execution

Dependend on the flow of dataBlock diagram does NOT executefrom left to right

Node executes when ALL input data areavailable

Nodes supply to all output terminalswhen done




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Debugging TechniquesFinding Errors

Click on the broken arrow button, LabVIEW will show an error list.

Execution Highlight

Click on Execution Highlight button;

Data flow will be visualized with bubbles and values.

Probe Values

Toggle On/Off Probe values.

Right-click on the wire of interest

context menu

Probe will display a probe window.Breakpoint

Set pauses at different locations on the diagram.Click on wires or objects with the Breakpoint tool to set breakpoints.




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Help

Show Context Help

Displays basic information about LabVIEWobjects. Objects with context help informationinclude VIs, functions, constants, structures,palettes, properties, methods, events, anddialog box components.

Open context help window

Ctrl + HHelp menu Show Context Help

Hover over nodes to update help window

Get detailed help

Click on Detailed help in Context Help

Right-click on the node, then choose HelpZabel/Brehm/Arnold 2010 11 / 47 ,



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Loops

WhileLoop

Run at least once (Do-While-Loop)

loop counter

loop stop conditionLoop runs until its input is True

ForLoop

loop counter

Run loop until number of iterations.




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g p g g p

Creating Loops

PaletteChoose the Structures partfrom Functions Palette

Drawing the loopEnclose code to be repeated.

Drag-and-Drop Nodes into

pre-defined structure.




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g p g g p

Sequences

Parallel Execution

All encapsulated codefragments areexecuted in parallel.

Sequence Execution

For sequentialcomutation create aSequence structure.




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Have fun using LabVIEW

Whish you a successful start using




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Example 1: Generate and save signals

Working directory:

cd /2010 LabviewCourse/example1

Task

Simulation of one time signal with variable properties

4096 Samples per second; 8192 samples per block

Save the time history as *.lvm file

Main VIs to use

Block Diagram Right Click Express Input Simulate SignalBlock Diagram Right Click Express Output Write Meas.File

Block Diagram Right Click Express Arith & Comp Comparison Comparison




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Example 1: Generate and save signalsSimulate signal Configuration




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Example 1: Generate and save signals

Front Panel proposal




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Example 1: Generate and save signalsBlock Diagram proposal




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Example 1: Generate and save signalsHead of .lvm file




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Example 2: Read and process data

Working directory:

cd /2010 LabviewCourse/example2

Task

Read and visualize a signal from an .lvm file

Calculate the averaged Power Spectrum of the signal

Main VIs to use

Block Diagram Right Click Express Input Read Meas. FileBlock Diagram Right Click Express Signal Analysis Spectral




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Example 2: Read and process dataRead file configuration




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Example 2: Read and process dataSpectral configuration




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Example 2: Read and process dataFront Panel proposal




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Example 2: Read and process data

Block Diagram proposal




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Task 1: Generate and save signals

Working directory:cd /2010 LabviewCourse/task1

Task: Add second signal

Based on Example 1 add a second signal with 4096 Samples persecond and 8192 samples per block

Save both signal as *.lvm file

Load the signals similar to Example 2 and calculate the Power

Spectrum

Main VIs to use

Same as in Example 1 and Example 2




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Structural system

System

k1

m1 k4

k2

k5

k6

m2

m3

k3

Measurement ofrandom signal at DOF 1

acceleration at all DOFs




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Task 3-1: Identify natural frequencies

Working directory:

cd /2010 LabviewCourse/task3 1

File information

data is in file Measured data.lvmColumns: | time | acce dof 1 - 3 | force dof 1 - 3 |No header information; Comma delimiter

block size for average: 8192

Task

Identify the natural frequencies of the structure




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Task 3-1: Identify natural frequenciesRead file configuration




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Example 3-2: Read and visualize transfer functions

Working directory:

cd /2010 LabviewCourse/example3 2

File information

data is in file H matrix rea.lvm

Columns: | H11 | H12 | H13 | H21 | H22 | H23 | H31 | H32 | H33 |No header information; Comma delimiter

Additional feature

Tab Control




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Example 3-2: Read and visualize transfer functionsRead file configuration




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Task 3-2: Add imaginary part

Working directory:


File information

data is in file H matrix ima.lvm

Columns: | H11 | H12 | H13 | H21 | H22 | H23 | H31 | H32 | H33 |No header information; Comma delimiter

Additional feature

Tab Control




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3 2


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E l 3 3


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Example 3-3:Calculate and visualize transfer functions

Task

Calculate the complex transfer function (Accelerance) based onmass-normalized eigenvectors [], eigenvalues

{

}and modal

damping ratios {}

Formula

[Hxf()] =

2 [][D()][]T (1)

(D())ll

=l 2

2ll

2l 2l2 + 4 + 4l22l

(2)



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Working directory:

cd /2010 LabviewCourse/example3 3Additional feature

Simple mathematical matrix and scalar operations

For-loop



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E l 3 3


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Task 3 3: Add imaginar part (Homework)


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Task 3-3: Add imaginary part (Homework)

Working directory:


Task

Add imaginary part of transfer function using Example 3-3

Additional feature

Use boolean switch



Task 3 3: Add imaginary part


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Task 3 3: Add imaginary part


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Documents

2010 Lab View Course Students