New graphics technologies give us some really stunning images of systems running on a human-machine interface (HMI), and they look very cool. We can virtually see tanks and watch them fill in blue corresponding to the water level; we can even see the rotating agitators. It’s almost like physically watching the equipment run, and we can do so from any remote HMI terminal that has access. We can add pumps that look like they’re spinning when they turn on and make the pipes turn colors to simulate fluid flow so we can pretend we’re actually watching what’s going on inside of them.
But is that really useful?
Over the past few years, a less flashy method of high-performance HMI development has been catching on, and for good reason. The simple goal of an HMI is to give operators a tool to perform their duties as effectively as possible—in other words, having a bunch of really cool graphics is not always a good thing. Companies all over the globe are rallying around the original idea that an HMI should display only what is important.
Take a look at the images above. Both depict similar processes, but the simpler one on the right immediately shows the operator whether or not the system is running as it should be. The one on the left does not. The fancy graphics actually make it harder for operators to analyze the system. They’re pretty, but they get in the way.
As reported in a presentation from PAS, “The High Performance HMI: Proper Graphics for Operator Effectiveness,” high-performance HMIs improve an operator’s ability to detect abnormal situations by a factor of 500 percent. They give operators a 37 percent better success rate over poorly designed HMIs in handling abnormal situations, and a 41 percent reduction in the time it takes to complete abnormal tasks they have identified.
In short, the next time you have to create an HMI, at least propose the idea for a high-performance HMI approach. Operators will usually hate it at first, but they will learn to like it once they are used to it.
Greg DeRubis, P.E., is senior engineer at Avanceon, a certified member of the Control System Integrators Association (CSIA). For more information about Avanceon, visit its profile on the Industrial Automation Exchange.