Poor HMI designs have been identified as factors contributing to abnormal situations, billions of dollars of lost production, accidents, and fatalities. Many HMIs actually impede rather than assist operators. Many of the poor designs are holdovers due to the limitations of early control systems and the lack of knowledge of system designers. However, with the advent of newer and more powerful systems, these limitations no longer apply. Also, decades of research has identified better implementation methods. Unfortunately, change is difficult and people continue to follow poor design practices. In fact, some new designs are actually worse than older designs! Just as a computer is not a typewriter, new HMI designs should not mimic those of old. The problem is that many designers often simply don’t know any better. This article will review why certain HMI designs are poor (with many examples) and show how they can be improved.
Paul Gruhn is a training manager at ICS Triplex, Rockwell Automation. Paul is an ISA Fellow, member of the ISA 84 standard committee (on safety instrumented systems), developer and instructor of ISA courses on safety systems, author of two ISA textbooks, two chapters in other books, and over two dozen published articles. He’s a developer of the first commercial safety system software modeling program. Paul received a bachelor’s degree in mechanical engineering from the Illinois Institute of Technology. This article was originally presented at the 66th Annual Instrumentation Symposium for the Process Industries in January 2011.