Experience with High Performance HMI at Two Durham WRFs


  • Daniel Edwards PE - Hazen and Sawyer
  • John Dodson, Charles Cocker, Newman Gunter - City of Durham, NC

The City of Durham was not satisfied with the existing Human-Machine Interface (HMI) software configuration at the North and South Durham Water Reclamation Facilities. As part of upgrade projects at both facilities, the City requested that the HMI software be upgraded to a current, more effective version. Hazen recommended that the City consider incorporating High Performance HMI (HPHMI) principles into the system.

HPHMI is a recent industry trend intended to increase operators’ situational awareness. Situational awareness is a concept long used in aviation and military training meaning that a person is aware and keeping track of nearby events and relationships that are relevant to safety and the mission at hand. HPHMI graphic displays generally feature muted colors except for alarm conditions allowing anything requiring operator attention to quickly stand out. HPHMI graphics emphasize providing information rather than raw data through bar graphs, trends and other conventions, allowing operators to instantly relate individual values to their normal operating ranges without having to remember the parameters for potentially hundreds of values. Like traditional graphics, HPHMI systems use hierarchical displays where different levels of displays provide different, appropriate levels of detail.

Understanding that this was a new concept, the project team held discussions during the design phase to define the intent and extent to which the principles should be incorporated. Once the basic concept was agreed upon, the control system design was adjusted to require HPHMI principles. To ensure City satisfaction with the project outcome, a series of four graphic workshops were stipulated to be performed by the system integrator during construction to promote a collaborative effort in graphic development. Considering that HPHMI graphics are not common in the water industry, the system integrator was pre-selected via an evaluated proposal procurement process to ensure the City would have a highly qualified project partner.

Following implementation, the City operations staff reports that the system has exceeded expectations. Operators have realized numerous benefits from the use of HPHMI, including fast and intuitive understanding of process status, instantaneous and obvious recognition of alarm states, a better understanding of recent as well as current performance, and a better ability to evaluate and control the unit processes, especially the critical BNR/aeration process. Specific examples, based on direct experience, of the benefits of using HPHMI graphics to monitor and control both facilities will be presented.

For more information, please contact the author at dedwards@hazenandsawyer.com.

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