Terry Blevins

Author's details

Date registered: April 19, 2011

Biography

Terry Blevins has been actively involved in the application and design of process control systems throughout his career. For more than 15 years, he worked as a systems engineer and group manager in the design and startup of advanced control solutions for the pulp and paper industry. Terry was instrumental in the establishment of Emerson Process Management's Advanced Control Program. From 1998-2005, Terry was the team lead for the development of DeltaV advanced control products. He is the Fieldbus Foundation™ team lead for the development and maintenance of the Function Block Specification and editor of the SIS Architecture and Model Specifications. In this capacity, Terry is involved in the movement of Fieldbus Foundation function block work into international standards. Terry is the U.S. expert to the IEC SC65E WG7 function block committee that is responsible for the IEC 61804 function block standards. He is a voting member and chairman of ISA104-EDDL (Electronic Device Description Language) committee and is the technical advisor to the United States Technical Advisory Group (USTAG) for the IEC65E subcommittee. He is also a member of the USNC TAG (IEC/SC65 and IEC/TC65). Terry authored "An Overview of the ISA/IEC Fieldbus," Section 11, Standards Overview, Fifth Edition of the Process/Industrial Instruments and Controls Handbook and coauthored four sections in the Fourth Edition of the Instrumentation Engineer's Handbook, Process Control and Optimization. He coauthored the ISA bestselling book Advanced Control Unleashed. He has 36 patents and has written over 65 papers on process control system design and applications. Terry received a Bachelor of Science in Electrical Engineering from the University of Louisville in 1971 and a Master of Science in Electrical Engineering from Purdue University in 1973. In 2004, he was inducted into Control Magazine's Process Automation Hall of Fame. Presently, Terry is a principal technologist in the future architecture team of DeltaV Product Engineering at Emerson Process Management.

Latest posts

  1. The Benefits of FDI Technology — June 17, 2013
  2. Application of Kalman Filtering in DeltaV — June 10, 2013
  3. Robustness-Based Tuning — June 3, 2013
  4. Commissioning PI Control – Integrating Process — May 27, 2013
  5. Surge Tank Control — May 20, 2013

Most commented posts

  1. Control Basics and Terminology — 1 comment
  2. Basics of Advanced Control — 1 comment

Author's posts listings

Jun
17

The Benefits of FDI Technology

Benefits of FDI Technology

The ISA104 Device Integration committee was established to develop or adopt, and to facilitate the application of standards and technical reports that represent device and interface descriptions for access of field devices in automation systems. In 2012 the scope of the committee was expanded to include the promotion of the Field Device Integration (FDI) standard, …

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Jun
10

Application of Kalman Filtering in DeltaV

Kalman Filter

A paper published in 1960 by Rudolf Kálmán “A New Approach to Linear Filtering and Prediction Problems” is the basis for the Kalman Filter. The Kalman filter has been successfully used in a wide variety of applications: • The guidance of commercial airplanes • Seismic data processing • Nuclear power plant instrumentation • Vehicle navigation …

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Jun
03

Robustness-Based Tuning

Robustness Map

Before tuning calculations are applied in a control loop, it is good to consider how much the process gain and deadtime can change before the loop becomes unstable. In the DeltaV control system, this information is provided using a robustness plot that shows gain margin and phase margin as illustrated below. Information on this type …

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May
27

Commissioning PI Control – Integrating Process

Three Element Drum Level Control

When the control objective is to maintain the controlled parameter of an integrating process at setpoint under all operating conditions, then using PI (proportional-integral or proportional plus reset) controller, it is possible to automatically compensate for changes in disturbance inputs and maintain the controlled parameter at setpoint. However, the application of PI control to an …

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May
20

Surge Tank Control

Surge Tank Level Control

Intermediate liquid storage tanks (surge tanks) are commonly installed between processing areas of the plant. Under normal operating conditions, these storage buffers allow each process area to be operated independently of the other process areas. Any imbalance in the area production rates within a plant will be reflected by a change in level of the …

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May
13

Easy to Apply Tuning Rules

Tuning PI Controller

Older control systems may not include tools that allow the PID tuning to be automatically established. In such cases, the following procedure outlined in Chapter 12 of Control Loop Foundation – Batch and Continuous Processes may be quickly applied to determine the tuning of a self-regulating process for PI control. In Chapter 4 of Advanced …

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May
06

On-demand Tuning Example

On-Demand Tuning Example

Control system manufacturers have adopted different technologies to implement on-demand tuning. Because these tools are designed to work in a noisy process measurement environment, the tuning results are usually better than those achieved through manual tuning techniques. To illustrate the features that may be included in on-demand tuning capability, the on-demand tuning capability of the …

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Apr
29

Selecting Control Response

After the process characteristics are identified, the information is then used to calculate the recommended loop tuning. The tuning rules used to derive controller parameters from process characteristics can be chosen as appropriate for the specific process and the desired speed of response. As addressed in Chapter 4 of Advanced Control Foundtion – Tools, Techniques, …

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Apr
22

Capturing Process Dynamics

Structuring On-demand Tuning

When the on-demand tuning application resides in a DCS workstation, communications between the controller and the workstation can introduce variable delay and jitter in the observed process response. As addressed in Chapter 4 of Advanced Control Foundation – Tools, Techniques, and Applications, the process may be more accurately identified by distributing the on-demand tuning functionality …

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Apr
15

On-Demand Tuning

Self Regulating Response

During the commissioning of feedback control based on the PID algorithm, the PID tuning parameters (that is, the proportional, integral, and derivative gain) must be set to specific values to achieve the best controller response to setpoint and disturbance input changes. To minimize process variations and the response time to setpoint and disturbance input changes …

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