Process Control Knowledge Base

 

Welcome to Control Station's Knowledge Base!  Here you will find information and insight related to a wide range of process control related topics.  Included is practical know-how regarding PID loop tuning best practice and recommended techniques for improving control in applications including boilers, reactors, distillation columns, heat exchangers and tank level control.  Advanced control strategies like Cascade and Feed-Forward are also covered.
 

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I. Modern Control is Based on Process Dynamic Behavior

 

1) Fundamental Principles of Process Control

Motivation and Terminology of Automatic Process Control
The Components of a Control Loop
Process Data, Dynamic Modeling and a Recipe for Profitable Control
Sample Time Impacts Controller Performance

2) Graphical Modeling of Process Dynamics: Heat Exchanger Case Study   

Step Test Data From the Heat Exchanger Process
Process Gain is the "How Far" Variable
Process Time Constant is the "How Fast" Variable
Dead Time is the "How Much Delay" Variable
Validating Our Heat Exchanger Process FOPDT Model

3) Modeling Process Dynamics: Gravity Drained Tanks Case Study   

The Gravity Drained Tanks Process
Dynamic "Bump" Testing of the Gravity Drained Tanks Process
Graphical Modeling of Gravity Drained Tanks Step Test
Modeling Gravity Drained Tanks Data Using Software

4) Software Modeling of Process Dynamics: Jacketed Stirred Reactor Case Study

Design Level of Operation for the Jacketed Stirred Reactor Process
Modeling the Dynamics of the Jacketed Stirred Reactor with Software
Exploring the FOPDT Model With a Parameter Sensitivity Study

 

II. PID Controller Design and Tuning

 

5) Process Control Preliminaries   

Design and Tuning Recipe Must Consider Nonlinear Process Behavior
A Controller's "Process" Goes From Wire Out to Wire In
The Normal or Standard PID Algorithm

6) Proportional Control - The Simplest PID Controller

The P-Only Control Algorithm
P-Only Control of the Heat Exchanger Shows Offset
P-Only Disturbance Rejection of the Gravity Drained Tanks

7) Caution: Pay Attention to Units and Scaling

Controller Gain is Dimensionless in Commercial Systems

8) Integral Action and PI Control

Integral Action and PI Control
PI Control of the Heat Exchanger
PI Disturbance Rejection of the Gravity Drained Tanks
The Challenge of Interacting Tuning Parameters
PI Disturbance Rejection in the Jacketed Stirred Reactor
Integral (Reset) Windup, Jacketing Logic and the Velocity PI Form

9) Derivative Action and PID Control

PID Control and Derivative on Measurement
The Chaos of Commercial PID Control
PID Control of the Heat Exchanger
Measurement Noise Degrades Derivative Action
PID Disturbance Rejection of the Gravity Drained Tanks

10) Signal Filters and the PID with Controller Output Filter Algorithm

Using Signal Filters In Our PID Loop
PID with Controller Output (CO) Filter
PID with CO Filter Control of the Heat Exchanger
PID with CO Filter Disturbance Rejection in the Jacketed Stirred Reactor
 
 

 

III. Additional PID Design and Tuning Concepts

 

11) Exploring Deeper: Sample Time, Parameter Scheduling, Plant-Wide Control  

  Sample Time is a Fundamental Design and Tuning Specification
Parameter Scheduling and Adaptive Control of Nonlinear Processes
Plant-Wide Control Requires a Strong PID Foundation

12) Controller Tuning Using Closed-Loop (Automatic Mode) Data

Ziegler-Nichols Closed-Loop Method a Poor Choice for Production Processes
Controller Tuning Using Set Point Driven Data
Do Not Use Disturbance Driven Data for Controller Tuning

13) Evaluating Controller Performance 

 C omparing Controller Performance Using Response Plot Data

 

 

IV. Control of Integrating Processes

 

14) Integrating (Non-Self Regulating) Processes

Recognizing Integrating (Non-Self Regulating) Process Behavior
A Design and Tuning Recipe for Integrating Processes
Analyzing Pumped Tank Dynamics with a FOPDT Integrating Model
PI Control of the Integrating Pumped Tank Process
 

 

V. Advanced Classical Control Architectures

 

15) Cascade Control For Improved Disturbance Rejection

The Cascade Control Architecture
An Implementation Recipe for Cascade Control
A Cascade Control Architecture for the Jacketed Stirred Reactor
Cascade Disturbance Rejection in the Jacketed Stirred Reactor

16) Feed Forward with Feedback Trim For Improved Disturbance Rejection

The Feed Forward Controller
Feed Forward Uses Models Within the Controller Architecture
Static Feed Forward and Disturbance Rejection in the Jacketed Reactor

17) Ratio, Override and Cross-Limiting Control


The Ratio Control Architecture
Ratio Control and Metered-Air Combustion Processes
Override (Select) Elements and Their Use in Ratio Control
Ratio with Cross-Limiting Override Control of a Combustion Process

18) Cascade, Feed Forward and Three-Element Control

 

Cascade, Feed Forward and Steam Boiler Level Control
Dynamic Shrink/Swell and Steam Boiler Level Control

 

VI. Process Applications in Control

 

19) Distillation Column Control

Introduction to Distillation Column Control
Major Disturbances & First-Level Distillation Column Control
Inferential Temperature & Single-Ended Column Control
Dual Composition Control & Constraint Distillation Column Control
 

20) Discrete Time Modeling of Dynamic Systems

A Discrete Time Linear Model of the Heat Exchanger

 

21) Fuzzy Logic and Process Control

Envelope Optimization and Control Using Fuzzy Logic

 

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