In my last article, I talked about how graphics is as much about what you don’t show as what you do show. So, this time I am discussing WHY we do that. Through studying human response mechanisms, we have learned that forms and shapes are easier to discern than numbers. Adding numbers to forms creates quick recognition and awareness.
As a point of reference, most of the instrumentation of the past generation (70’s/80’s) was designed using what we termed “behavioral psychology” and today we use the term “human factors engineering”. Behavior psychologists studied how humans gathered INFORMATION, and designed instrumentation for control panels to indicate information at a glance without further study. Let me show you an example. Some of us are old enough to remember when automobiles went to totally digital dashes. (they have since reverted). Example: you are driving down the highway and you see a speed limit sign.
You look at your digital speedometer. It shows you this:
You subtract 60 from 75, and calculate you are 15 mph over the limit, and if you calculate further, you realize that is 25% over the limit. You had better slow down and do it quickly in case a constable is nearby with a digital readout of his own.
Now, imagine trying to do that with a screen FULL of numbers, and calculate the differences between settings and current values, and making control decisions. Or, imagine using that graphic I shared with you last time, while driving down the highway at 75 mph. Simply cannot be done with any expectancy of success. Yet, we do that every day with operators to “help” them control extremely valuable and dangerous processes.
Now, instead, suppose you looked down and saw this:
Your mind immediately tells you that you are approximately 25% over the speed limit without doing any calculations at all because you can see the space between the needle and the 60.
So, how do we cure this problem? The solution is called “Situational Awareness Graphics”. Situational awareness graphics is a result of designing graphics to the purpose for which they are needed. We show ONLY the important information that drives the proper control and notifications required to perform that control. Most times, it does not have shapes of process equipment on the graphics unless they are pertinent and lend understanding.
Let me drive a notion out of anybody’s head about one thing Situational Awareness Graphics is NOT. It is NOT just gray backgrounds to remove color confusion. I have seen simple “gray-ifcation” fail every time it has been undertaken. It is not so much the color that drives the problem, it is the shapes and layout, and how the eye is drawn (or not) to certain objects in the visual layout. ALL that gray screens do is remove one more confusing issue from the playing field. Consider these points:
- P&ID diagrams don’t get any easier to read when they are gray. There is nothing inherent about that color that makes them more understandable.
- Gray backgrounds must accompany an increase in light levels in the control room. Otherwise, they tend to glare at the user. If light levels are not increased, users will clamor for their dark backgrounds to return (and usually succeed).
- P&ID’s may have a value- but usually at what we term a “Level 3” or “Level 4” diagram that is used to get down to intense troubleshooting. Most Level 1 and Level 2 graphics are intended to give overviews of entire processes or plant areas, to avoid having to use detailed graphics by keeping things within the rails- i.e. they are overviews. Kind of like the dashboard on your car.
- Many people complain that they worry they are going to lose their P&ID view of the process that they use to troubleshoot. NO- that is NOT the case. They are just a couple of levels down because they simply contain TOO MUCH granularity of information to view them all the time while also taking in what else is going on. Reiterating: they are still there, just not prominent.
So, to be successful, human factors scientists must work with the intended users to discover WHAT they need to visualize and make apparent. Then the science of the work comes into drawing upon templates and libraries of proven shapes and techniques that MINIMIZE the amount of space necessary to show the MAXIMUM information (as opposed to just data). And mainly, not in a manner that confuses. Accomplish this, and you have a Situational Awareness Graphic.
So, let’s revisit the modern dashboard on a car- It contains just the information needed to operate the vehicle, and alarms to alert you if a further problem exists. And newer ones have drill-down to allow you to look deeper if you need to do so. And if you have a serious problem (Check engine light on full time), there are troubleshooting interfaces allowing deeper looks at the operational specifics. Think of this like the level 3 diagrams on a plant. The car is taken off line to do this, because it doesn’t require the 24/7 availability of a process plant. If you take your car to the shop, they use these Level 3/ Level 4 inspection graphics.
I hope this is helping the vision of Situational Awareness Graphics value, and differences. Next blog I’ll shift gears (pun intended) to some other valuable information around Operator Performance.