6- Hou r Hands -O n

Introduction to LabVIEW

Co ur se Goals

• Become comfortable with the LabVIEW environment and data flow execution

• Ability to use LabVIEW to solve problems• LabVIEW Concepts

– Acquiring, saving and loading data– Find and use math and complex analysis functions– Work with data types, such as arrays and clusters– Displaying and printing results

Th e Vir tual I nstru menta t ion Ap pro ach

La bVI EW Grap hical De velop ment S yst em

• Graphical Programming Environment• Compile code for multiple OS and devices• Useful in a broad range of applications

Virtua l Inst rumen tat ion App li ca t io ns• Des ign

– Signal and Image Processing– Embedded System Programming

• (PC, DSP, FPGA, Microcontroller)– Simulation and Prototyping– And more…

• Control– Automatic Controls and Dynamic Systems– Mechatronics and Robotics– And more…

• Meas urem ents– Circuits and Electronics– Measurements and Instrumentation– And more…

Design Prototype Deploy

A single graphical development platf orm

The NI Approach – Integrated Hardware Platforms

Hig h-S peedDig itiz ers

Hig h -Reso lu tio nDig itiz e rs a nd DMM s

Mu lti functio n Da ta Acq u isi t ion

Dyn amicS igna l A cqu is itio n

Dig ita l I/ OIn stru me n tContro l

Counter/T ime rs

Mach ineV isio n

Mo tio n Con tro l

D istr ib u te d I/O a ndEmb edded Con tro l

Lapto p P C PDADeskto p P CPXI Mo dula r In stru me n ta ti on

S igna l C ond itio n in gand Sw itch in g

Un it Under T est

Sect io n I – La bVI EW En vir onme ntA. Getting Data into your Computer

• Data Acquisition Devices– NI-DAQ– Simulated Data Acquisition– Sound Card

B. LabVIEW Environment• Front Panel / Block Diagram• Toolbar /Tools Palette

C. Components of a LabVIEW Application• Creating a VI• Data Flow Execution

D. Additional Help• Finding Functions• Tips for Working in LabVIEW

A. Sett in g Up Yo ur Ha rd wa re

• Data Acquisition Device (DAQ)– Actual USB, PCI, or PXI Device– Configured in MAX

• Simulated Data Acquisition Device (DAQ)– Software simulated at the driver level– Configured in MAX

• Sound Card– Built into most computers

Track ATrack A

Track BTrack B

Track CTrack C

Do No t De lete– Notes on hardware setup

What type of device s hould I us e?

xxx—Trigg er ing

x

AC/DC

2–4

16–80

—

14–18 bit

250 K–1. 2 Ms/ s

NI PC I DAQ

somexxPor ta ble

20kS/s–2 GS/ s10–200 KS/s

8–44 KS/sAI Band widt h

x

AC/DC

0

2

12–24 bi t

Instruments*

x

AC/DC

1–2

8–16

12–16 bit

NI USB DAQ

—Ca li brated

ACAC or D C

2AO Ch annels

2AI Ch annels

12–16 bi tAccur ac y

Sound Card*

* T he abo ve tab le may no t be rep resen tative of al l de v ice varia t ions that exist i n ea ch c ategory

What is MA X?• MAX stands for Measurement & Automation Explorer.

• MAX configures and organizes all your National Instruments DAQ, PCI/PXI instruments, GPIB, IMAQ, IVI, Motion, VISA, and VXI devices.

• Used for configuring and testing devices.

Icon Found onIcon Found on

Windows DesktopWindows Desktop

Ex ercis e 1 – Se tting Up Your Device• Use Measurement and Automation Explorer (MAX) to:

– Configure and test your Data Acquisition (DAQ) device

Track ATrack A

Do No t De leteEx ercis e Inst ruct ions

Ex ercis e 1 – Se tting Up Your Device• Use Measurement and Automation Explorer (MAX) to:

– Configure and test your Simulated Data Acquisition (DAQ) device

Track BTrack B

Do No t De leteEx ercis e Inst ruct ions

Ex ercis e 1 – Se tting Up Your Device•Use Windows to:

–Verify your Sound Card

Track CTrack C

Un-Mute Microphone

Sta rt »Al l P ro grams »N ation al In st ruments LabVIE W

Sta rtu p Scr een:

Start from a Blank VI :

New»Blan k VI

Start from an Example:

Ex am ples»F ind Ex amples …

»

or

Open and Run LabVIEW

Each VI has 2 Windows

Fr ont P anel• User Interface (UI)

– Controls = Inputs– Indicators = Outputs

Block D iagram• Graphical Code

– Data travels on wires from controls through functions to indicators

– Blocks execute by Dataflow

LabVIEW Programs Are Called Virtual Instruments (VIs)

Con trols Pale t te(Con trols & Indicator s)

(Place items on the Front Panel Window)

Indicator:Numeric Slide

Control:Numeric

Cu sto mize Pa lett e

Vi ew

Fun ction s (a nd Structure s) Pa lett e

(Place items on the Block Diagram Window)

Structure:While Loop

• Recommended: Automatic Selection Tool• Tools to operate and modify both front panel and

block diagram objects

Operating Tool

Positioning/Resizing Tool

Labeling Tool

Wiring Tool

Tools Palette

Automatic Selection Tool

Automatically chooses among the following tools:

Run Button

Continuous Run Button

Abort Execution

Execution Highlighting Button

Additional Buttons on the Diagram Toolbar

Status Toolbar

Retain Wire Values Button

Step Function Buttons

Do Not DeleteExercis e Instr uc t ions

Block Diagram Window

Front Panel Window

Demonstration 1: Creating a VI

InputTerminals

OutputTerminal

BooleanControl

GraphIndicator

• Block diagram execution– 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

Da taf low Pro gr amming

Debugging Techniques• Finding Errors

• Execution Highlighting

• Probes

Click on broken Run button.Window showing error appears.

Click on Execution Highlighting button; data flow is animated using bubbles. Values are displayed on wires.

Right-click on wire to display probe and it shows data as it flows through wire segment.

You can also select Probe tool from Tools palette and click on wire.

Exercis e 2 – Acquiring a S ignal wit h DA QTrack A&BTrack A&B

This exercise should take 15 minutes.

• Use a LabVIEW template to:– Acquire a signal from your DAQ

device

Do No t De leteEx ercis e Inst ruct ions

Do No t De leteEx ercis e Inst ruct ions

Do No t De leteEx ercis e Inst ruct ions

Exercis e 2 – Acquiring a S ignal wit h th e S ound Card

Track CTrack C

• Use LabVIEW to:– Acquire a signal from your sound card

This exercise should take 15 minutes.

Co ntext Help Wi ndo w• Help»Sh ow Con text Help , press the <Ctrl+H> keys

• Hover cursor over object to update windowAdd i t ional He lp

– Right-Click on the VI icon and choose Help, or

– Choose “De tai le d Help.” on the context help window

Tips f or W or kin g in La bVI EW

• Keystroke Shortcuts– <Ctrl+H> – Activate/Deactivate Context Help Window– <Ctrl+B> – Remove Broken Wires From Block Diagram– <Ctrl+E> – Toggle Between Front Panel and Block

Diagram

– <Ctrl+Z> – Undo (Also in Edit Menu)

• Tools»Options… – Set Preferences in LabVIEW• VI Properties–Configure VI Appearance, Documentation, etc.

Blank Page – Do no t D elete

Sect io n I I – E le men ts of Typical Pro gra msA. Loops

• While Loop• For Loop

B. Functions and SubVIs• Types of Functions• Creating Custom Functions (SubVI)• Functions Palette & Searching

C. Decision Making and File IO• Case Structure• Select (simple If statement)• File I/O

Lo ops

•While Loops– i terminal counts iteration– Always runs at least once– Runs until stop condition is

met

• For Loops– i terminal counts iterations– Run according to input N of

count terminal

While LoopWhile Loop

For LoopFor Loop

Drawing a Loop

1. Select the structure

2. Enclose code to be repeated

3. Drop or drag additional nodes and then wire

3 Types of Fu nct io ns ( f rom t he Fu nct ions Palett e)Express VIs: interactive VIs with configurable dialog page (b lue b or de r)

Standard VIs: modularized VIs customized by wiring (cus tomizable)

Functions: fundamental operating elements of LabVIEW; no front panel or block diagram (ye l lo w)

What Type s of Fu nctions are Availab le?• Inpu t and O ut pu t

– Signal and Data Simulation– Acquire and Generate Real Signals with DAQ– Instrument I/O Assistant (Serial & GPIB)– ActiveX for communication with other programs

• Ana lys is – Signal Processing– Statistics– Advanced Math and Formulas– Continuous Time Solver

• Sto ra ge– File I/O

Express Functions Palette

Sea rc hing for Con trols, VI s, a nd Fun ction s• Palettes are filled with hundreds

of VIs• Press the search button to index the

all VIs for text searching• Click and drag an item from the

search window to the block diagram • Double-click an item to open the

owning palette

Ex ercis e 2.1 – An alys is Track A,B,&CTrack A,B,&C

• Use LabVIEW Express VIs to:– Simulate a signal and display its amplitude and frequency

This exercise should take 15 minutes.

Do No t De leteEx ercis e Inst ruct ions

Ex ercis e 2.2 – An alys is Track A&BTrack A&B

• Use LabVIEW Express VIs to:– Acquire a signal and display its amplitude and frequency

This exercise should take 15 minutes.

Ex ercis e 2.2 – An alys is Track CTrack C

• Use LabVIEW Express VIs to:– Acquire a signal and display its amplitude and frequency

This exercise should take 15 minutes.

Ho w Do I Make De ci sion s in La bVIEW ?1. Case Structures

7. Select(a) (b)

(c )

File I /O

• File I/O – Allows recording or reading data in a file. • LabVIEW creates or uses the following file formats:

– Binary: underlying file format of all other file formats– ASCII: regular text files– LVM: LabVIEW measurement data file– TDM: created for National Instruments products

Hi gh Le vel File I/O Fu nct io ns

• Easy to use• High Level of abstraction

Writing to LVM fileWriting to LVM file Reading from LVM fileReading from LVM file

Exercis e 3.3 – Deci sion M ak ing and S av ing Dat a• Use a case structure to:

– Make a VI that saves data when a condition is met

This exercise should take 15 minutes.

Track A,B,CTrack A,B,C

File I/ O Pro gr amming Mo del – U nd er t he hood

Ope n/Cre at e/

Re plac e F i le

Rea d and/ or

Wr i te t o File

Cl ose File

Che ck forEr ro rs

Spr ead sheet Form at tin g

• Spreadsheet files are ASCII files with a certain formatting– Usually tabs between columns and end of line constants

between rows– LabVIEW includes VIs that perform this formatting or a string

can be concatenated

Do No t De leteEx ercis e Inst ruct ions

Do No t De leteEx ercis e Inst ruct ions

Sect io n I II – Pre senting your Re sul tsA. Displaying Data on the Front Panel

• Controls and Indicators• Graphs and Charts• Loop Timing

B. Signal Processing• MathScript• Arrays• Clusters• Waveforms

What Types of Con trols and In di cat ors are Available?• Numer ic Dat a

– Number input and display– Analog Sliders, Dials, and Gauges

• Boolean Da ta– Buttons and LEDs

• Array & Mat ri x Da ta– Numeric Display– Chart– Graph– XY Graph– Intensity Graph– 3D graph: point, surface, and model

• Dec or at ions– Tab Control– Arrows

• Other– Strings and text boxes– Picture/Image Display– ActiveX Controls

Express Controls Palette

Cha rts – A dd 1 d ata point at a t im e wit h historyWaveform chart – special numeric indicator that can display a history of values

• Chart updates with each individual point it receives

Functions»Express»Graph Indicators»Chart

Graph s – Dis play ma ny data poin ts at onc eWaveform graph – special numeric indicator that displays an array of data

• Graph updates after all points have been collected• May be used in a loop if VI collects buffers of data

Functions»Express»Graph Indicators»Graph

• Loops can accumulate arrays at their boundaries with auto-indexing

• For Loops auto-index by default

• While Loops output only the final value by default

• Right-click tunnel and enable/disable auto-indexing

Build ing Arr ay s with Lo op s (Auto-Inde xin g)

Wire becomes thicker

Wire remains the same size

Aut o-Indexing Dis abl ed

Auto-I ndexing Enabl ed

Only one value (last iteration) is passed out of the loop

1D Array

0 1 2 3 4 5

5

Cr ea t in g an Arr ay (St ep 1 of 2)From the Controls»Modern»Array, Matrix, and Cluster subpalette, select the Array icon.

Drop it on the Front Panel.

Cr ea te an Arra y (Step 2 o f 2)1. Place an Array Shell.

2. Insert datatype into the shell (i.e. Numeric Control).

Ho w Do I Time a Lo op ?1. Loop Time Delay

• Configure the Time Delay Express VI for seconds to wait each iteration of the loop (works on For and While loops).

2. Timed Loops• Configure special timed While loop for desired dt.

Timed LoopTime Delay

Co ntro l & I ndicator Pro pe rt ies• Properties are characteristics or qualities about an object• Properties can be found by right clicking on a Control or Indicator

• Properties Include:– Size– Color– Plot Style– Plot color

• Features include:– Cursors– Scaling

Ex ercis e 3.1 – Ma nua l An alys is Track A,B,&CTrack A,B,&C

• Use the cursor legend on a graph to:– Verify your frequency and amplitude measurements

This exercise should take 15 minutes.

Textual Math in La bVIE W• Integrate existing scripts with LabVIEW for faster development• Interactive, easy-to-use, hands-on learning environment• Develop algorithms, explore mathematical concepts, and

analyze results using a single environment• Freedom to choose the most effective syntax, whether

graphical or textual within one VI

Su pp or ted M ath Too ls :MathScript script node MathSoft softwareMathematica software MATLAB® softwareMaple software Xmath software

MATLAB ® is a registered trademark of The MathWorks, Inc.

Math w it h the Math Scrip t N ode• Implement equations and algorithms textually• Input and Output variables created at the border• Generally compatible with popular m-file script language• Terminate statements with a semicolon to disable immediate

output

Prototype your equations in the interactive Mat hS cript W indo w.

(F unc t ions»P rogram ming »Structures »Mat hSc ri pt)

The Inter act ive MathScrip t W in dow• Rapidly develop and test algorithms

(LabV IEW»Tools »Math Scr ipt Window )

Out putWind ow

Va ria bleWo rk spac

e

View/ Mod ifyVar iable

Co nte ntsUser

Commandsm-f il e Sc ri pt

• Share Scripts and Variables with the Node

• View /Modify Variable content in 1D, 2D, and 3D

Ex ercis e 3.2 – Using MathScrip tUse the MathScript Node and Interactive Window to process the acquired signal (logarithmic decay) in the MathScript and save the script.

Track A,B,&CTrack A,B,&C

This exercise should take 25 minutes.

Do No t De lete

Exercise Instructions

Do No t De lete

Exercise Instructions

Re vi ew of Da ta Type s Fou nd in L abVIE W

Exerc is e 3.3 – A ppl y What Yo u Hav e LearnedTrack A,B,&CTrack A,B,&C

This exercise should take 20 minutes.

Sect io n I V – A ddition al Lab VI EW Top ic s

A. Additional Data types• Cluster

B. Data Flow Constructs• Shift Register

C. SubVIs

D. State Machines

E. Local Variables

F. Producer/Consumer

Int rod uct io n t o Clusters

• Data structure that groups data together

• Data may be of different types

• Analogous to struct in C

• Elements must be either all controls or all indicators

• Thought of as wires bundled into a cable

• Order is important

Cr ea t in g a Clu ster• Select a Cl ust er shell.

Contro ls »M odern»Arra y, Matr ix & Cluste r

2. Place objects inside the shell.

Cl us te r F unct ions• In the Cluster & Variant subpalette of the

Programming palette• Can also be accessed by right-clicking the cluster

terminal

Bundle

(Terminal labels reflect data type)

Bundle By Name

Using A rra ys and Clust ers wit h G ra phs

The Waveform Datatype contains 3 pieces of data:• t0 = Start Time• dt = Time between Samples• Y = Array of Y magnitudes

Two ways to create a Waveform Cluster:

Build Waveform (absolute t ime) Cluster (relat iv e ti me)

Shift Register – Access Previous Loop Data• Available at left or right border of loop structures• Right-click the border and select Ad d Sh if t Re gis ter • Right terminal stores data on completion of iteration• Left terminal provides stored data at beginning of next iteration

Before Loop

BeginsFirst

IterationSecondIteration

LastIteration

Val ue 3Ini t ia lVa lu e

Mod ula rity in La bVI EW – Sub VI s

Convert repeated functions and VIs with a single VI

Crea te Su bVI• Enclose area to be converted into a subVI.

• Select Edit» Create S ubVI from the Edit Menu.

LabVIEW Functions and SubVIs operate like Functions in other languages

Fu nct ion Ps eudo Co defunction average (in1, in2,

out){out = (in1 + in2)/2.0;}

Su bV I Bl ock Dia gr am

Ca l li ng Pr og ra m P se udo Co de

main{average (in1, in2, pointavg)}

Ca l li ng VI Bl ock Diag ra m

Ic on and Con nector Pan e

• Use this connector pane layout as a standard

• Top terminals are usually reserved for references, such as a file reference• Bottom terminals are

usually reserved for error clusters

Ic on and Con nector Pan e – Cr ea te Ic on

• Create custom icons by right-clicking the icon in the upper right corner of the front panel or block diagram and selecting Ed it Ic on or by double-clicking the icon

• You also can drag a graphic from anywhere in your file system and drop it on the icon

• Refer to the Icon Art Glossary at ni.com for standard graphics to use in a VI icon

Do No t De leteEx ercis e Inst ruct ions

Do No t De leteEx ercis e Inst ruct ions

St ate Ma chine s

• While Loop• Case Structure• Shift Register

St ate Ma chine s Tra nsit io ns

• Several programming techniques exist for transitioning from state to state in LabVIEW using State Machines

• Default transition implies that after one state, another state always follows

• Transitions between two potential states can be handled by a Select Function

Co mmun ic at in g betw ee n l oop s•Communicating between loops using data flow is not possible

•The left loop will execute completely before the right loop

•Variables are needed when communication with wires does not give the desired behavior

Local Variables• Local Variables allow data to be passed between parallel loops.• A single control or indicator can be read or written to from more than one location in the program

– Local Variables break the dataflow paradigm and should be used sparingly

Crea ting a Local Variable - Walk Throu gh

In this example we will see how Local Variables allow us to share data between parallel loops. We will create a program that toggles two separate LEDs using one switch. It also stops two loops with one button.

Create the block diagram and front panel as seen to the right.

Cr ea t in g Loca l Var iab les

Right-click on the Stop Button in the Front Panel and change the Mechanical Action to “Switch When Released” since Local Variables cannot store Latched data.

Producer/Con sum er Design Pat tern

V. La rg e Pr og ram D evelop ment

A. Navigation Window

B. LabVIEW Project

C. Shared Variable

• Shows the current region of view compared to entire Front Panel or Block Diagram

• Great for large programs

La bVI EW Naviga t io n W in dow

* Organize and reduce program visual size with subVIs

La bVI EW Pr oject

• Group and organize VIs• Hardware and I/O management• Manage VIs for multiple targets• Build libraries and executables• Manage large LabVIEW applications• Enable version tracking and management

(Lab VI EW» Pr ojec t»Ne w)

Sha red Va riab les

• Shared Variables are used to send data between VIs. • Variable Types:

– Single Process: share the data among VIs on the local computer.– Network-published: communicate between VIs, remote

computers, and hardware through the Shared Variable Engine.

• Shared Variable must exist within a project library.• Shared Variable must be deployed to be available to other projects

and remote computers.

Do No t De lete Ex ercis e Inst ruct ions

Do No t De leteEx ercis e Inst ruct ions

Sect io n V I - I nstru men t Co ntro l

A. Overview of Instrument Control

B. GPIB

C. Serial

D. Instrument I/O Assistant

E. VISA

F. Instrument Drivers and IDNET

Wha t Types of I ns trum ents Can Be Con trolled?

• GPIB• Serial• Modular Instruments• PXI Modular Instruments• Image Acquisition• Motion Control• USB• Ethernet• Parallel Port• CAN

GPI B

• General Purpose Interface Bus (GPIB)• GPIB is usually used in stand alone bench top instruments to control measurements and communicate data

• Digital 8-bit parallel communication interface• IEEE 488.1 and 488.2 define standards for GPIB

Ser ial

• Serial communication transmits one bit at a time over a transmission line

• Usually does not require external hardware• Four parameters: baud rate, data bits, parity bit, stop bits

Inst rumen t I/ O As sist ant

• LabVIEW Express VI used to communicate with message-based instruments

• Communicate with an instrument that uses a serial, Ethernet, or GPIB interface

• Use the Instrument I/O Assistant when an instrument driver is not available

Do Not DeleteExercis e Instr uc t ions

Do Not Delete Exercis e Instr uc t ions

VI SA

• Virtual Instrumentation Software Architecture (VISA)• High-level API that calls low-level drivers• Can control VXI, GPIB, serial, or computer-based instruments

• Makes appropriate driver calls depending on the instrument used.

Inst rumen t D rivers

• Plug and Play drivers are a set of VIs that control a programmable instrument

• VIs correspond to instrument operation: configuring, triggering, and reading measurements

• Help getting started since programming protocol for each instrument is already known

IDN ET

• Instrument Driver Network (IDNET)• Instrument Driver Finder within LabVIEW

To ols » In str um ent ation » Find In str um en t Dr ivers

He lp » Find I nst ru men t Driv ers

• Can be found online at www.ni.com/idnet

Add itio nal R es our ces• NI Academic Web & Student Corner

– http://www.ni.com/academic

• Connexions: Full LabVIEW Training Course– www.cnx.rice.edu

– Or search for “LabVIEW basics”

• LabVIEW Certification– LabVIEW Fundamentals Exam (free on www.ni.com/academic)

– Certified LabVIEW Associate Developer Exam (industry recognized certification )

• Get your own copy of LabVIEW Student Edition– www.ni.com/academic By Robert H Bishop.

Published by Prentice Hall. Updat ed f or

LabVIEW 8

Th e LabVIEW Ce rtif ic at io n Pro gra m

Ce rtifie d L ab VIEW De velop er

Certifie d L abVIEW Asso ciat e De velo pe r

Certified LabVI EW Ar ch itec t

Architect• Mastery of LabVIEW • Expert in large application development• Skilled in leading project teams

Developer• Advanced LabVIEW knowledge

and application development experience

• Project management skills

Associate Developer• Proficiency in navigating

LabVIEW environment• Some application development experience

Fundam ental s Ex am•Pre-Certification Skills Test Fr ee O n-L ine Fu ndamen tals Fr ee O n-L ine Fu ndamen tals

Exa mExa m

Elect roni cs Wor kbench an d Multis im

• World’s most popular software for learning electronics

• 180,000 industrial and academic users• Products include:

– Multisim: Simulation and Capture– Multi-MCU: Microcontroller Simulation– MultiVHDL: VHDL Simulation

– Ultiboard: PCB Layout

– Electronics CBT: Computer-based training

• Low cost student editions available• www.electronicsworkbench.com

Multisim Integ rated wit h Lab VIEW1. Create Schematic 2. Virtual Breadboard 3. Simulate

4. PCB Layout 5. Test 6. Compare

You r Next Step …

Take the free LabVIEW Fundamentals Exam at ni.com/academic

Your first step to become LabVIEW Certified!

Do No t De leteEx ercis e 1.2 So luti ons

Do No t De leteEx ercis e 2.1 So luti ons

Do No t De leteEx ercis e 2.2 So luti ons

Do No t De leteEx ercis e 3.3 So luti ons

Do No t De leteEx ercis e 2.4 So luti ons

Do No t De leteEx ercis e 3.1 & 3.2 Solution s

Do No t De leteEx ercis e 3.3 So luti ons

Do No t De leteEx ercis e 4.1 So luti ons

Do No t De leteEx ercis e 4.2 So luti ons

Do No t De leteEx ercis e 5.1 So luti ons

Do No t De leteEx ercis e 6.1 So luti ons