#1430 - Application of Feedback Controllers and Use of Advanced Control Applications

Course Objective

This course is a combination of basic course 1410 and advanced course 1420.  Upon completion of this course, participants will understand basic controllers along with learning how to apply and tune advanced controllers.  It covers the use of basic feedback controllers in the process industries and the practical, successful methods to tune them.  This course also presents methods for applying advanced controllers with practical step-by-step methods that utilize relationships and reaction curve analysis. These methods can be easily understood and implemented by the individual immediately.

Who Should Attend

Technicians, engineers, operators, trainers, sales personnel, maintenance, management personnel, and scientists who are involved in the processing industries:  refineries, chemical plants, power stations, water plants, etc.  Some knowledge of control in the process industry would be beneficial.

Course Description

This course presents practical step-by-step tuning methods that utilize relationships and reaction curve analysis.  It covers the benefits of feedforward, adaptive or scheduled gain, and dead time compensation.  This course provides practical and useful ideas of how to tune feedforward controllers in the processing industries without requiring advanced mathematics.  It presents how to implement adaptive or scheduled gain to improve control and provide non-continuous control.  Participants will understand the methods for handling dead time in a process.  The course will stress the fact that improved control will provide better productivity and efficiencies.

Participants will be able to:

• Understand how a controller works and how it fits into a process
• Know the parts of a control loop
• Understand the fundamentals of controller gain or proportional band, integral and derivative actions
• Tune a controller by trail and error
• Improve on the trial and error method by using special rules
• Apply the ultimate oscillation tuning method to properly tune feedback controllers
• Determine tuning constants by using modifications of the ultimate oscillation method
• Run response curves on a process
• Identify controller problems by analyzing the response curve
• Measure gain, dead time, and process lag of a process
• Determine what controller gain or proportional band, integral and derivative actions are best to control the process
• Understand the difference between set point change and load change
• Apply tuning methods to cascade controllers
• Identify when process changes may be needed for improved control
• Recognize when advanced controls are beneficial
• Understand what feedforward control is and its benefits
• Run plant tests to determine feedforward relationships
• Calculate the feedforward constants
• Understand what adaptive or scheduled gain is and its benefits
• Calculate adaptive gains for non-linear processes
• Apply error squared controllers on level controllers
• Understand how dead time compensators work
• Tune dead time compensators
• Use different methods to improve control of processes with dead time
• Identify when process changes may be needed for improved control

   The course consists of the following main topics and subtopics:

• Relationship of controller and process
  • Four parts of a process
  • Interaction of changes to the four parts
  • Benefits of good control
• Definitions of the controller modes:  gain, integral, and derivative
• Rules for improved trail and error tuning
• Analysis of oscillation responses
  • Tuning using oscillation techniques
• Analysis of response curves
  • Tuning using a response curve generated by a step change
  • Tuning using a response curve produced by a load change
  • Working with unusual response curves
• Changes that may be required in the process to improve controllability
• Use of cascade control
• Review of feedback tuning
• Description and benefits of feedforward controllers
  • Tests required to obtain feedforward constants
  • Calculation of the feedforward constants
• Description and benefits of adaptive or scheduled gain
  • Methods to tune controllers with adaptive gain
  • Use of adaptive gain to provide control of non-linear processes
  • Using adaptive gain to provide special effects
• Limits, step changes, transmitter failure protection, surge control, etc.
• Analysis of processes with excessive dead time
  • Dead time compensators
  • Tuning dead time processes with PID only
  • Small changes to a process to provide improved control
• Application of error squared controllers for level control
• Understanding changes that may be required in the process

The following exercises are included in this course

• Individual participants will calculate tuning constants using various methods and will calculate controller constants based on data from handouts (Note:  Calculators are useful)
• As a class, trial and error measurement will be studied and various methods will be performed using a PC based computer program

Course Duration - 2 or 3 days