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Control Systems Operations

5 November 9:15 a.m. - 10:45 a.m.

Session Type: Paper

Track: Industrial Automation and Control

Paths(s): TechnicianTechnician   MarketingMarketing   EngineerEngineer   Academia/R&D/ScientistAcademia/R&D/Scientist   


Everything You Need to Know About Bad PV But Were Afraid to Ask

Lee Swindler, Maverick Technologies Read Bio
Lee Swindler is a Program Manager at Maverick Technologies based out of Houston with 25 years of automation experience in the Oil & Gas and Chemicals industries. Lee previously worked for LyondellBasell where he spent 18 years in a variety of positions including projects, maintenance, plant control systems and corporate engineering. Lee has served on a number of user committees and API standard development teams. Lee has a BS in electrical engineering from the South Dakota School of Mines and Technology.


Will your control system respond correctly when an instrument fails or goes out of range?  Are you using sound practices to determine and manage Bad PV settings?  For many companies, there is significant room for improvement in this area.  Learn about potential consequences resulting from improper Bad PV settings along with commonly made errors.  Proper threshold settings, shed mode and extended range will be explained along with recommended practices to allow your control system to function as intended during Bad PV situations.  This presentation is recommended for anyone involved with the determination, implementation or management of Bad PV settings in any control system.

Situation Awareness: A Primer for Process Operations

Klaus Christoffersen Ph.D., Acuite Read Bio

Klaus combines a background in both research and applied aspects of human-systems integration issues. He holds a PhD in Industrial and Systems Engineering, focusing on cognitive aspects of Human Factors Engineering. For the past decade the focus of his work has been developing advanced HMIs for process control, with a focus on the oil and gas and mineral processing sectors. Before joining Acuite in 2007 he advised clients in various industries including mineral and petrochemical processing, healthcare, transportation, defense and NASA space operations.


As more and more emphasis is placed on supporting operator performance in the process industries, it is important to understand how concepts from outside process control can be used to inform improvement efforts. Developed primarily in the context of aviation and military applications, Situation Awareness (SA) is becoming a popular term when discussing monitoring in process control settings. In everyday terms, having good situation awareness (SA) just means “knowing what’s going on” around you. Based on this simple definition it's easy to agree that having good SA is (or certainly ought to be!) very important to someone operating a complex, dynamic and potentially hazardous process. But what does SA really mean? What makes it difficult to build and maintain SA in the context of process operations? What design strategies can we use to support it? This article provides some background on the concept of situation awareness and takes a critical look at how it can be used to provide a new perspective on improving process operations.

A New Perspective on the Tuning, Stability, and Benefits of Cascade Control

Jacques Smuts Ph.D., P.E., OptiControls Inc Read Bio

Jacques Smuts is the founder and principal consultant of OptiControls Inc (League City, Texas). He has a Ph.D. from the University of Johannesburg, and 22 years of experience in process control. He is a licensed professional engineer in Texas and a senior member of the International Society of Automation (ISA).

Jacques has analyzed and optimized thousands of control loops and solved control problems in power, refining, oil and gas, chemical, pulp & paper, food processing, and other industries. He has developed controller tuning and control loop performance monitoring software that is being used in process plants around the world.

Jacques has developed process control training seminars and presented this training to hundreds of practicing engineers and technicians on five continents. He has published more than a dozen technical papers and articles, and is the author of the book “Process Control for Practitioners”. 


It is often said that for a cascade control system to be stable, the outer loop should be tuned for a significantly slower response than the inner loop. However, the minimum ratio of outer to inner loop response time required for stability is subject to some dispute. This paper explores the minimum response-time ratio required for cascade control systems to be stable, and the effect that process characteristics and tuning methods have on this minimum. Some surprising results regarding response-time ratios and loop stability are presented.

It has also been recommended that for cascade control to be beneficial, the inner loop in a cascade control system must respond at least five times faster than the outer loop. This paper analyzes some typical, but distinctly different, cascade control applications and evaluates their benefits. It shows that in practice, cascade control is not always applied for improving control performance and explains how cascade control is sometimes applied solely to simplify a control strategy.

The paper makes recommendations about the type of tuning methods that should be used to obtain stable, responsive cascade control systems. It also provides guidance about predicting the benefits that may be reaped from implementing cascade control on different process types.