Enhancing Process Control Efficiency: A Practical Approach to Large-Scale Controller Performance Assessment

Publication: A practical approach for large-scale controller performance assessment, diagnosis, and improvement.

Authors: Michael A. Paulonis, John W. Cox

Publication Summary

Eastman Chemical Company has developed a large-scale controller performance assessment system that spans over 14,000 PID controllers in 40 plants at 9 sites worldwide. The system allows for sorting controllers by performance, tracking improvement or degradation in performance, and providing diagnostic aids for troubleshooting. E-mail reports are automatically generated to keep users informed of relevant changes. The system has increased controller optimization productivity at Eastman Chemical Company.

What is the purpose of the controller performance assessment system developed by Eastman Chemical Company?

The purpose of the controller performance assessment system developed by Eastman Chemical Company is to monitor and track the performance of over 14,000 PID controllers in various plants worldwide. It allows for sorting controllers by performance, identifying those that need attention, tracking improvement or degradation in performance, and providing diagnostic aids for troubleshooting. The system aims to increase controller optimization productivity and facilitate efficient detection and diagnosis of problems in control loops.

What features are available in the system to assist with troubleshooting?

The system offers several features to assist with troubleshooting. These include:

  1. E-mail reports: Users can subscribe to daily or monthly reports for specific process areas of interest. These reports provide information on controller performance and any changes or issues detected.
  2. Detailed performance assessments: Users can access detailed assessments of closed-loop operating data for individual controllers. These assessments include summary text sections, time-series plots of setpoint, measurement, and output data, numerical statistics, and graphical analyses. Pop-up help is available to assist users in understanding the graphs and statistics.
  3. Diagnostic aids: The system provides diagnostic information in text form, allowing users to identify potential hardware problems or other issues affecting controller performance. The system also offers performance history and problem diagnosis information, including tuning history and analysis, loop configuration information, and more.

These features help users quickly identify controllers needing attention, diagnose controller problems, and track controller performance over time, reducing troubleshooting time and improving overall control loop efficiency.

How are users kept informed of relevant changes?

Users are kept informed of relevant changes through the daily tuning change report, which is sent to their email inbox once per day. This report lists controllers that have had tuning changes in the past day, alerting users to potential problems in their process area. The report serves as a reliable and timely way to communicate tuning changes and potential issues to users. Additionally, users can subscribe to a variety of daily or monthly reports for process areas of interest, which are sent to them via HTML email. These reports provide summary statistics, loop performance rankings, and highlight changes in loop performance, allowing users to stay updated on the performance of their controllers.

What impact has the system had on controller optimization productivity?

The system developed by Eastman Chemical Company has had a significant impact on controller optimization productivity. By implementing the performance assessment system, Eastman Chemical Company has been able to rank controllers by performance, easily monitor the overall performance of controllers in an entire plant or process area, and quickly identify controllers needing attention. This has led to substantial productivity gains and other benefits. The system has allowed for the transformation of huge amounts of process data into concise and valuable information for plant personnel. It has also resulted in reduced off-class production, reduced product property variability, lower operating costs, improved production rates, and reduced controller alarms and operator interventions. Overall, the system has enhanced controller optimization productivity and facilitated efficient detection and diagnosis of problems in control loops.

Are there any future enhancements planned for the assessment system?

The ongoing work aims to enhance the system in the areas of problem diagnosis, closed-loop identification, and detection of plant-wide distributed disturbances. The system plans to improve problem diagnosis capability by employing nonlinear time-series signatures, automated pattern recognition, and an improved diagnostic rule base. Additionally, there is a focus on improving closed-loop model identification to provide more accurate tuning recommendations and enhance problem diagnoses related to poor tuning. These enhancements will further improve the system’s capabilities and effectiveness in optimizing controller performance.