Introduction To Labview 8 In 6 Hours

Introduction to LabVIEW

6- Hou r Hands -O n

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 tion 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 tio ns • Des ign – Signal and Image Processing – Embedded System Programming

A single graphical development

platf orm

• (PC, DSP, FPGA, Microcontroller)

– Simulation and Prototyping Design – And more… • Control – Automatic Controls and Dynamic Systems – Mechatronics and Robotics – And more… • Meas urem ents – Circuits and Electronics – Measurements and Instrumentation – And more…

Prototype

Deploy

The NI Approach – Integrated Hardware Platforms

P XI Mo d ula r In stru me n ta ti o n

Hig h-S pe edHig h -R eso lu tio n Mu lti functio n Dyn a mic In stru me n t Dig itiz ers Dig itiz e rs a nd DMM sDa ta Acq u isi tio nS ig nal A cq uis itio n Co ntro l

S ig nal C o nd itio nin g a nd Sw itch in g

Un it Und er T est

Dig ita l I/ O

Deskto p P C

Cou nter/ T ime rs

M ach in e V isio n

La pto p P C

Mo tio n Con tro l

Distr ib u te d I/O a nd E mb e dd ed Con tro l

P DA

Sect io n I – La bVI EW En vir onme nt A. 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)

Track A

– 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

Track C

– Built into most computers

Track B

Do No t De lete – Notes on hardware setup

What type of device s Sound Card*

hould I us e? NI PC I DAQ

12–16 bi t

NI USB DAQ 10–200 KS/s bit 12–16

Por ta ble

x

x

—

some

AI Ch annels AO Ch annels AC or D C

2

8–16

16–80

2

2

1–2

2–4

0

AC

AC/DC

AC/DC

AC/DC

Trigg er ing

—

x

x

x

Ca li brated

—

x

x

x

AI Band widt h Accur ac y

8–44 KS/s

250 K–1. 2 Ms/ sbit 14–18

abo ve tab le may no t be rep resen tative of all de vice varia tions that exist

Instruments* 20kS/s–2 GS/

i n ea ch c ategory

12–24 bi t

s

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 on Windows Desktop

Ex ercis e 1 – Se tting Up Your Device

Track A

• Use Measurement and Automation Explorer (MAX) to: – Configure and test your Data Acquisition (DAQ) device

Do No t De lete Ex ercis e Inst ruct ions

Ex ercis e 1 – Se tting Up Your Device

Track B

• Use Measurement and Automation Explorer (MAX) to: – Configure and test your Simulated Data Acquisition (DAQ) device

Do No t De lete Ex ercis e Inst ruct ions

Ex ercis e 1 – Se tting Up Your Device • Use Windows to: – Verify your Sound Card

Un-Mute Microphone

Track C

Open and Run LabVIEW 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 or Start from an Example:

Ex am ples»F ind Ex amples …

LabVIEW Programs Are Called Virtual Instruments (VIs) 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

Con trols Pale tte (Place items on the Front Panel Window) (Con trols & Indicator s) Control: Numeric

Cu sto miz e Pa lett e Vi ew

Indicator: Numeric Slide

Fun ction s (a nd Structure s) Pa lett e (Place items on the Block Diagram Window)

Structure: While Loop

Tools Palette • Recommended: Automatic Selection Tool • Tools to operate and modify both front panel and block diagram objects Automatic Selection Tool Automatically chooses among the following tools: Operating Tool Positioning/Resizing Tool Labeling Tool Wiring Tool

Status Toolbar Run Button Continuous Run Button Abort Execution

Additional Buttons on the Diagram Toolbar Execution Highlighting Button Retain Wire Values Button Step Function Buttons

Do Not Delete Exercis e Instr uc tions

Demonstration 1: Creating a VI Front Panel Window

Graph Indicator Block Diagram Window

Output Terminal

Boolean Control Input Terminals

Da taf low Pro gr amming • 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

Debugging Techniques • Finding Errors Click on broken Run button. Window showing error appears.

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

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

This exercise should take 15 minutes.

Track A&B

a S ignal wit h DA Q

Do No t De lete Ex ercis e Inst ruct ions

Do No t De lete Ex ercis e Inst ruct ions

Do No t De lete Ex ercis e Inst ruct ions

Exercis e 2 – Acquiring Card

a S ignal wit h th e S ound

• Use LabVIEW to:

– Acquire a signal from your sound card

This exercise should take 15 minutes.

Track C

Co ntext Help Wi ndo w • Help»Sh ow Con text Help , press the keys • Hover cursor over object to update window Add itional He lp – Right-Click on the VI icon and choose Help, or – Choose “De taile d Help.” on the context help window

Tips f or W or kin g in La bVI EW • Keystroke Shortcuts – – Activate/Deactivate Context Help Window – – Remove Broken Wires From Block Diagram – – Toggle Between Front Panel and Block Diagram – – 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 ms A. 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 Loop

• 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

For Loop

Drawing a Loop 2. Enclose code to be repeated 1. Select the structure

3. Drop or drag additional nodes and then wire

3 Types of

Fu nct io ns

(from 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 llo 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 lysis – – – –

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,&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 lete Ex ercis e Inst ruct ions

Ex ercis e 2.2 – An alys is

Track 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 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)

(c )

(b)

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 file

Reading from LVM file

Track A,B,C

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.

File I/ O Pro gr amming Mo del – U nd er t he hood Ope n/ Cre at e/ Re plac e F ile

Rea d and/ or Wr ite t o File

Cl ose File

Che ck for Er 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 lete Ex ercis e Inst ruct ions

Do No t De lete Ex ercis e Inst ruct ions

Sect io n I II – Pre senting your A. Displaying Data on the Front Panel • Controls and Indicators • Graphs and Charts • Loop Timing

B. Signal Processing • • • •

MathScript Arrays Clusters Waveforms

Re sul ts

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 history Waveform 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 e Waveform 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

Build ing Arr ay s with Lo op s (AutoInde xin g) Auto-I ndexing Enabl ed

• 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 autoindexing

Wire becomes thicker

1D Array 012345

Aut o-Indexing Dis

abl ed

Wire remains the same size

5

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

Cr ea tin 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.

Time Delay

Timed Loop

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,&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 Mathematica software Maple software

MathSoft software MATLAB® 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

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

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

The Inter act ive MathScrip

t W in dow

• Rapidly develop and test algorithms • Share Scripts and Variables with the Node • View /Modify Variable content in 1D, 2D, and 3D Out put Wind ow

m-f il e Sc ri pt

User Commands

(LabV IEW » Tools Window )

Va ria ble Wo rk spac e View/ Mod ify Var iable Co nte nts

» Math Scr ipt

Ex ercis e 3.2 – Using MathScrip

t

Track A,B,&C

Use the MathScript Node and Interactive Window to process the acquired signal (logarithmic decay) in the MathScript and save the script.

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

Track A,B,&C

Exerc is e 3.3 – A ppl y What Yo u Hav e Learned 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 •

C. D. E. F.

Shift Register

SubVIs State Machines Local Variables 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 tin g a Clu ster •

Select a Cl ust er shell.

2. Place objects inside the shell.

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

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

(Terminal labels reflect data type) Bundle

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

time)

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 ift Re gis ter • Right terminal stores data on completion of iteration • Left terminal provides stored data at beginning of next iteration

Initial Va lu e

Before Loop Begins

Val ue 3

First Iteration

Second Iteration

Last Iteration

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 de function average (in1, in2, out) { out = (in1 + in2)/2.0; }

Su bV I Bl ock Dia gr am

Ca lli ng Pr og ra m P se udo Co de main { average (in1, in2, pointavg) }

Ca lli 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 doubleclicking 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 lete Ex ercis e Inst ruct ions

Do No t De lete Ex 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 atin 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 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.

gh

Cr ea tin 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

La bVI EW Naviga tio n W in dow

• Shows the current region of view compared to entire Front Panel or Block Diagram • Great for large programs

* 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 lete Ex ercis e Inst ruct ions

Sect io n V I - I nstru men t Co ntro l A. B. C. D. E. F.

Overview of Instrument Control GPIB Serial Instrument I/O Assistant VISA 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 Delete Exercis e Instr uc tions

Do Not Delete Exercis e Instr uc tions

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 )

or f • Get your own copy of LabVIEW Student Edition d te 8 a d – www.ni.com/academic Up VIEW By Robert H Bishop. Lab

Published by Prentice Hall.

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Do No t De lete Ex ercis e 1.2 So luti ons

Do No t De lete Ex ercis e 2.1 So luti ons

Do No t De lete Ex ercis e 2.2 So luti ons

Do No t De lete Ex ercis e 3.3 So luti ons

Do No t De lete Ex ercis e 2.4 So luti ons

Do No t De lete Ex ercis e 3.1 & 3.2 Solution

s

Do No t De lete Ex ercis e 3.3 So luti ons

Do No t De lete Ex ercis e 4.1 So luti ons

Do No t De lete Ex ercis e 4.2 So luti ons

Do No t De lete Ex ercis e 5.1 So luti ons

Do No t De lete Ex ercis e 6.1 So luti ons