Tag Archive: process

Apr
14

IEC TC65 Standards Work

IEC Webstore

The international standards for industrial-process measurement, control and automation are developed through IEC TC65. As stated on the IEC web site, the standards developed by TC65 address systems and elements used for industrial-process measurement and control concerning continuous and batch processes. These standards address equipment and systems operating with electrical, pneumatic, hydraulic, mechanical or other …

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Feb
17

High Speed Wireless Control

I was recently sent a link to a YouTube video of a control demonstration by professor Raffaello D’Andrea, The Institute for Dynamic Systems and Control at ETH, Swiss Federal Institute of Technology, Zurich. ETH is one of the world’s leading universities for technology and the natural sciences. I found the demonstration by Professor D’Andrea to …

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Oct
28

Process Education on Demand

Process Eduation on Demand

In Emerson’s boot camp for new engineers, I teach the portion on process control based on our book Control Loop Foundation – Batch and Continuous Processes. Each student receives a copy of this book. Customer may receive the same process control training by attending a 4 ½ day class, Control Loop Foundation – 9025, offered …

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Aug
26

Neural Networks for Property Estimation

Non-linear Property Estimation Based on Upstream Measurements

One of the key objectives of a process control system is to maintain product quality parameters within specifications. An on-line analyzer may not be available to make a sampled or continuous measurement of a physical property or the composition of a liquid or gas stream, or other conditions may prevent their use. In such a …

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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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