LabVIEW Graphical Programming

LabVIEW Graphical Programming

Authors: Gary Johnson and Richard Jennings

Published: July 2006

eISBN: 9780071501538 0071501533 | ISBN: 9780071451468

Contents

Preface

Acknowledgments

Chapter 1 Roots

LabVIEW and Automation

Virtual instruments: LabVIEW's foundation

Why use LabVIEW?

The Origin of LabVIEW

Introduction

A vision emerges

All the world's an instrument

A hard-core UNIX guy won over by the Macintosh

Putting it all together with pictures

Favoring the underdog platform for system design

Ramping up development

Stretching the limits of tools and machine

Facing reality on estimated development times

Shipping the first version

Apple catches up with the potential offered by LabVIEW

LabVIEW 2: A first-rate instrument control product becomes a world-class programming system

The port to Windows and Sun

LabVIEW 3

LabVIEW 4

LabVIEW branches to BridgeVIEW

LabVIEW 5

The LabVIEW RT branch

LabVIEW 6

LabVIEW 7

LabVIEW 8

Crystal Ball Department

LabVIEW influences other software products

LabVIEW Handles Big Jobs

Chapter 2 Getting Started

About the Diagrams in This Book

Sequencing and Data Flow

LabVIEW under the Hood

The parts of a VI

How VIs are compiled

Multitasking, multithreaded LabVIEW

The LabVIEW Environment

Front panel

Controls

Property nodes

Block diagram

SubVIs

Icons

Polymorphic VIs

Data

Clusters

Typedefs

Arrays

Debugging

See what the subVIs are up to

Peeking at data

One step at a time

Execution highlighting

Setting breakpoints

Suspend when called

Calling Other Code

CINs

Dynamic link libraries

Programming by Plagiarizing

Bibliography

Chapter 3 Controlling Program Flow

Sequences

Data Dependency

Adding Common Threads

Looping

While LOOPS

For Loops

Shift registers

Uninitialized shift registers

Globals

Global and local variables

Built-in global variables—and their hazards

Local variables

Events

Notify and Filter events

Mechanical actions

Dynamic events

Design Patterns

Initialize and then loop

Independent parallel loops

Client-server

Client-server (with autonomous VIs)

State machines

Queued message handler

Event-driven applications

Bibliography

Chapter 4 LabVIEW Data Types

Numeric Types

Strings

Building strings

Parsing strings

Dealing with unprintables

Spreadsheets, strings, and arrays

Arrays

Initializing arrays

Array memory usage and performance

Clusters

Waveforms

Data Type Conversions

Conversion and coercion

Intricate conversions and type casting

Flatten To String (. . . Do what?)

Enumerated types (enums)

Get Carried Away Department

Chapter 5 Timing

Where Do Little Timers Come From?

Using the Built-in Timing Functions

Intervals

Timed structures

Timing sources

Execution and priority

Timing guidelines

Sending timing data to other applications

High-resolution and high-accuracy timing

Bibliography

Chapter 6 Synchronization

Polling

Events

Occurrences

Notifiers

Queues

Semaphores

Me and You, Rendezvous

Chapter 7 Files

Accessing Files

File Types

Writing Text Files

Reading Text Files

Formatting to Text Files

Binary Files

Writing binary files

Reading binary files

Writing Datalog Files

Reading Datalog Files

Datalog file utilities

Chapter 8 Building an Application

Define the Problem

Analyze the user's needs

Gather specifications

Draw a block diagram

Specify the I/O Hardware

Prototype the User Interface

Panel possibilities

First Design and Then Write Your Program

Ask a Wizard

Top-down or bottom-up?

Modularity

Choose an architecture: Design patterns

The VI hierarchy as a design tool

Sketching program structure

Pseudocoding

Ranges, coercion, and default values

Handling errors

Putting it all together

Testing and Debugging Your Program

Tracing execution

Checking performance

Final Touches

VBL epilogue

Studying for the LabVIEW Certification Exams

CLAD

CLD

Example 1: Traffic light controller

Example 2: Car wash controller

Example 3: Security system

Bibliography

Chapter 9 Documentation

VI Descriptions

Control Descriptions

Custom Online Help

Documenting the Diagram

VI History

Other Ways to Document

Printing LabVIEW Panels and Diagrams

Putting LabVIEW screen images into other documents

Writing Formal Documents

Document outline

Connector pane picture

VI description

Terminal descriptions

Programming examples

Distributing Documents

Chapter 10 Instrument Driver Basics

Finding Instrument Drivers

Driver Basics

Communication standards

Learn about Your Instrument

Determine Which Functions to Program

Establish Communications

Hardware and wiring

Protocols and basic message passing

Bibliography

Chapter 11 Instrument Driver Development Techniques

Plug-and-Play Instrument Drivers

General Driver Architectural Concepts

Error I/O flow control

Modularity by grouping of functions

Project organization

Initialization

Configuration

Action and status

Data

Utility

Close

Documentation

Bibliography

Chapter 12 Inputs and Outputs

Origins of Signals

Transducers and sensors

Actuators

Categories of signals

Connections

Grounding and shielding

Why use amplifiers or other signal conditioning?

Choosing the right I/O subsystem

Network everything!

Bibliography

Chapter 13 Sampling Signals

Sampling Theorem

Filtering and Averaging

About ADCs, DACs, and Multiplexers

Digital-to-analog converters

Digital codes

Triggering and Timing

A Little Noise Can Be a Good Thing

Throughput

Bibliography

Chapter 14 Writing a Data Acquisition Program

Data Analysis and Storage

Postrun analysis

Real-time analysis and display

Sampling and Throughput

Signal bandwidth

Oversampling and digital filtering

Timing techniques

Configuration Management

What to configure

Configuration editors

Configuration compilers

Saving and recalling configurations

A Low-Speed Data Acquisition Example

Medium-Speed Acquisition and Processing

Bibliography

Chapter 15 LabVIEW RT

Real Time Does Not Mean Real Fast

RT Hardware

Designing Software to Meet Real-Time Requirements

Measuring performance

Shared resources

Multithreading and multitasking

Organizing VIs for best real-time performance

Context switching adds overhead

Scheduling

Timed structures

Communications

Bibliography

Chapter 16 LabVIEW FPGA

What Is an FPGA?

LabVIEW for FPGAs

RIO hardware platforms

Plug-in cards

CompactRIO

Timing and synchronization

Compact Vision

Application Development

Compiling

Debugging

Synchronous execution and the enable chain

Clocked execution and the single-cycle Timed Loop

Parallelism

Pipelining

Conclusions

Bibliography

Chapter 17 LabVIEW Embedded

Introduction

History

LabVIEW Embedded Development Module

The technology: What's happening

Running LabVIEW Embedded on a new target

Porting the LabVIEW runtime library

Incorporating the C toolchain

The Embedded Project Manager

LEP plug-in VIs

Target_OnSelect

Other plug-in VIs

Incorporating I/O srivers

LabVIEW Embedded programming best practices

Interrupt driven programming

LabVIEW Embedded targets

Chapter 18 Process Control Applications

Process Control Basics

Industrial standards

Control = manipulating outputs

Process signals

Control system architectures

Working with Smart Controllers

Single-loop controllers (SLCs)

Other smart I/O subsystems

Man-Machine Interfaces

Display hierarchy

Other interesting display techniques

Handling all those front panel items

Data Distribution

Input scanners as servers

Handling output data

Display VIs as clients

Using network connections

Real-time process control databases

Simulation for validation

Sequential Control

Interlocking with logic and tables

State machines

Initialization problems

GrafcetVIEW—a graphical process control package

Continuous Control

Designing a control strategy

Trending

Real-time trends

Historical trends

Statistical process control (SPC)

Alarms

Using an alarm handler

Techniques for operator notification

Bibliography

Chapter 19 Physics Applications

Special Hardware

Signal conditioning

CAMAC

Other I/O hardware

Field and Plasma Diagnostics

Step-and-measure experiments

Plasma potential experiments

Handling Fast Pulses

Transient digitizers

Digital storage oscilloscopes (DSOs)

Timing and triggering

Capturing many pulses

Recovering signals from synchronous experiments

Handling Huge Data Sets

Reducing the amount of data

Optimizing VIs for memory usage

Bibliography

Chapter 20 Data Visualization, Imaging, and Sound

Graphing

Displaying waveform and cartesian data

Bivariate data

Multivariate data

3D Graphs

Intensity Chart

Image Acquisition and Processing

System requirements for imaging

Using IMAQ Vision

IMAQ components

Sound I/O

DAQ for sound I/O

Sound I/O functions

Sound input

Sound output

Sound files

Bibliography

Index