Employing a User-Centered Design Approach to Improve Operator Interfaces

OCCUPATIONAL APPLICATIONS On the strength of ethnographic, task analysis, and co-discovery data collected at a research-focused institute at a major southwest U.S. university and at a major refinery plant, redesign recommendations were generated for a major distributed control system user interface. Demonstrating the value of the user-centered design and task-based approach, a series of generalizable design guidelines were derived, including those intended to reduce operators’ load, increase intuitiveness of manipulation, and increase the ease with which operators could cooperate to make control decisions. A case study is presented involving the collaboration of software developers, users, and academic researchers, highlighting the contribution of Information Science to distributed control system design, and arguing for a general decision- and task-based design approach to distributed control system user interface design.TECHNICAL ABSTRACT Rationale: In a refinery or other complex control room, the operator station allows operators to rapidly assess a set of distinct systems or situations under their span of control and determine where attention is needed on a moment-by-moment basis. If a problem exists, the overview display directs the operators to displays from which they can troubleshoot and correct the problem. Purpose: An extant distributed control system product and workflow were examined, a user-centered design approach to a redesign was applied, and discernment of generalizable design guidelines was sought. Methods: This article focuses on understanding the needs of the operator and using task-based analysis to improve the overall design of operator displays. First, an ethnography and a task analysis were performed from two separate control room sites. Second, the types of tasks and work environments that are appropriate for the operator were considered. Finally, the operators and engineers were given our redesign ideas, employing a co-discovery method. Results: Various points in the current product design were found where mental calculations or cognitive associations of data parameters with the systems they represented caused undue increases in the operators’ cognitive load. Places were also found where slavish echoing of piping and instrumentation diagrams in the product user interface led to inefficiencies for the operators. Conclusions: User interface redesigns steeped in cognitive and perceptual psychology and information science are presented, and an argument is made for a general decision- and task-based design approach to distributed control system user interface design. The collaboration of software developers, users (operators and engineers), and academic researchers is highlighted.