pid control toolset.pdf

PID Control Toolset

User Manual

PID Control Toolset User Manual

November 2001 Edition

Part Number 322192A-01

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The LabVIEW PID Control Toolset is covered by one or more of the following Patents: U.S. Patent No(s).: 6,081,751

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Contents

About This Manual

Organization of This Manual .........................................................................................ix

Conventions Used in This Manual.................................................................................ix

Related Documentation..................................................................................................x

Chapter 1

Overview of the PID Control Toolset

Package Contents ...........................................................................................................1-1

System Requirements ....................................................................................................1-1

Installation Procedure ....................................................................................................1-1

PID Control Toolset Applications .................................................................................1-2

PID Control....................................................................................................................1-2

Fuzzy Logic ...................................................................................................................1-3

How Do the Fuzzy Logic VIs Work?..............................................................1-3

Advanced Control ..........................................................................................................1-4

P ART I

PID Control

Chapter 2

PID Algorithms

The PID Algorithm ........................................................................................................2-1

Implementing the PID Algorithm with the PID VIs .......................................2-2

Error Calculation...............................................................................2-2

Proportional Action...........................................................................2-2

Trapezoidal Integration .....................................................................2-2

Partial Derivative Action ..................................................................2-2

Controller Output ..............................................................................2-3

Output Limiting.................................................................................2-3

Gain Scheduling ..............................................................................................2-4

The Advanced PID Algorithm .......................................................................................2-4

Error Calculation...............................................................................2-4

Proportional Action...........................................................................2-4

Trapezoidal Integration .....................................................................2-5

The Autotuning Algorithm ............................................................................................2-6

Tuning Formulas .............................................................................................2-6

PID Control Toolset User Manual

Contents

Chapter 3

Using the PID Software

Designing a Control Strategy ........................................................................................ 3-1

Setting Timing................................................................................................. 3-2

Tuning Controllers Manually.......................................................................... 3-3

Closed-Loop (Ultimate Gain) Tuning Procedure ............................. 3-4

Open-Loop (Step Test) Tuning Procedure ....................................... 3-5

Using the PID VIs ......................................................................................................... 3-6

The PID VI...................................................................................................... 3-6

The PID Advanced VI..................................................................................... 3-7

Bumpless Automatic-to-Manual Transfer ........................................ 3-7

Multi-Loop PID Control ................................................................................. 3-8

Setpoint Ramp Generation .............................................................................. 3-9

Filtering Control Inputs................................................................................... 3-10

Gain Scheduling .............................................................................................. 3-11

Control Output Rate Limiting ......................................................................... 3-13

The PID Lead-Lag VI ..................................................................................... 3-13

Converting Between Percentage of Full Scale and Engineering Units........... 3-14

Using the PID with Autotuning VI and the Autotuning Wizard..................... 3-14

Using PID with DAQ Devices ...................................................................................... 3-17

Software-Timed DAQ Control Loop .............................................................. 3-17

Implementing Advanced Function in Software-Timed

DAQ Control Loops .................................................................................... 3-18

Hardware-Timed DAQ Control Loop............................................................. 3-19

Chapter 4

Process Control Examples

Simulation VIs............................................................................................................... 4-1

Tank Level ...................................................................................................... 4-1

General PID Simulator.................................................................................... 4-3

Plant Simulator................................................................................................ 4-5

Cascade and Selector ...................................................................................... 4-6

Demonstration VIs......................................................................................................... 4-8

PID with MIO Board....................................................................................... 4-8

Lead-Lag ......................................................................................................... 4-11

PID Control Toolset User Manual

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