Controller Tuning (ACTAV)

Learn the basics of instrument control, the principles behind three methods of tuning a controller, as well as step-by-step tuning procedures.

Prerequisites

This lesson is designed for participants familiar with the basics of instrument control including the proportional, integral, and derivative control modes.

Description

This lesson explains tuning methods and principles behind the three methods of tuning a controller: ultimate, reaction curve, and trial and error. The lesson presents the characteristics of a properly timed process response and relates these to proportional, integral, and derivative control actions. In addition, step-by-step procedures for tuning controllers using each method are demonstrated.

Objectives

Define controller tuning and its purpose as used in a process control system. Define a process response. Explain the significance of a 1/4 decay reaction curve. Perform the preliminary steps for tuning a controller. Stabilize a process on manual control before using the ultimate method. Obtain the value of and calculate the proper setting for a proportional band or gain. Find the value of the ultimate period. Calculate the proper settings for PI, PD, and PID controllers. Verify adjustments. Obtain and interpret a process reaction curve.

Calculate the process gain, dead time, time constant, and controller settings using the reaction curve method. Interpret a process response to determine the proper setting. Using the trial and error method, tune the proportional mode.