Tag Archive: tuning

May
05

Control Loop Foundation Reprint

Manual Tuning Integrating Process

A book goes through many reviews and edits before it can be published. Still, it is very difficult for the authors and reviewers to catch all the typo’s in the original text and those that are introduced during the type setting process (formatting for publication). ISA recently notified me that the book that Mark Nixon …

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Sep
02

Boot Camp for New Employees

bootcamp

In 2012 Emerson Process Management established a boot camp for new employees. In the boot camp I teach the classes on process control. The presentation I use in boot camp is based on material and process examples from our book Control Loop Foundation – Batch and Continuous Processes. The students in the boot camp use …

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Aug
19

Fuzzy Logic Control – Example

Process for Fuzzy Logic Workshop

In this fuzzy logic control workshop contained in Chapter 6 of Advanced Control Foundation – Tools, Techniques, and Applications, the control performance of fuzzy logic control is be compared to the performance of PID control. For this example, the control objective is to reach setpoint in minimum time with no overshoot. Two identical process heaters …

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Aug
12

Fuzzy Logic Control – Commissioning

Tuner Interface for Fuzzy Logic Control

To allow consistent implementation of control applications, fuzzy logic control may be implemented as a function block. The fuzzy rules and membership functions can be predefined except for the scaling of the membership functions for error, change in error, and change in output.  As addressed in Chapter 6 of Advanced Control Foundation – Tools, Techniques, …

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Aug
05

Fuzzy Logic Control – Implementation

Predefined Fuzzy Logic Control Function Block

To minimize the time needed to apply fuzzy logic control, most manufacturers offer a version of fuzzy logic control in which the rules and membership functions are pre-defined. As described in Chapter 6 of Advanced Control Foundation – Tools, Techniques, and Applications, , a manufacturer can provide support for auto-tuning by restricting the fuzzy logic …

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Jul
29

Fuzzy Logic Control

Fuzzy Logic vs PID Control Performance

Fuzzy logic is a relatively new control technology. In the mid-1970s Mamdani began to investigate fuzzy logic as an alternative to the PID controller and sparked the first practical applications of fuzzy logic in the process control industry. The controller followed rules that generated an output by evaluating the error and the change in error. …

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Jul
22

Adaptive Tuning – Example Application

Adaptive Tuning Example

It is often possible to spot where adaptive control is needed by observing trends of control loops that show the control parameter and valve position during a time period when the process conditions change over their normal span of operation. If the control performance varies with changes in operating conditions, then adaptive tuning may be …

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Jul
15

Adaptive Tuning – Field Experience

Batch Reactor Process

The adaptive tuning capability included in DeltaV was field tested at four customer sites during the initial stages of product development. This field trail was conducted over a six month period and include over 1000 control loops. One of the field trail sites was at Lubrizol, Deer Park, TX where this adaptive control capability was …

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Jul
08

Adaptive Tuning – Models Identified

Viewing Identified Models

The basis of adaptive tuning is the identification of the process step response based on operator changes in the loop operation. For example, when a control loop is in Automatic mode, changes made in the setpoint can trigger process model identification. If the loop mode has been changed to Manual, then changes by the operator …

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Jul
01

Adaptive Tuning – Model Switching

Adaptive PID Controller With Model Switching and Parameter Interpolation

During the development of the DeltaV adaptive tuning capability, we researched and evaluated many of the most common techniques for implementing adaptive tuning. Also, as part of this research we came across a number of technical articles on a relative new adaptive tuning technique known as model switching. This technique depends on the evaluation of …

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