Why High Performance HMI Is Often Misunderstood in the Control Room
The processing industry has evolved from physical instruments on a panel to electronic physical controllers on the panel to a limited group of 8 faceplates on a black background which replicated the electronic controllers.
The industry identified that this limited view did not show the context of the faceplate and relied on the operator mental model to piece together the controls with the physical equipment. To correct this perception the Automation vendors provided what was state of the art graphic capabilities for their systems. The only reference point users had to connect the controls and the equipment was the P&ID which is used to design and build the plant. Unfortunately, this did not represent how the plant operates so many controls were dispersed over the graphics and not aligned for operations control making navigation of controls and control moves a nightmare.
The limited computing power meant that these graphics would be on a black background and use some very bright colors with broken coding systems. The coding system of color was often lost by not dedicating a color to one code but using that same color multiple times for different codes, hence, when something important happened like a “red” high priority alarm it did not stand out on a graphic covered in red for many other things like closed valves, stopped motors, heaters, steam systems, etc.
Two colors that were overused and often meant the opposite coding condition such as open versus closed was “Red” and “Green” unfortunately the two predominant colors many humans have problems with are red and green together, color deficient or more commonly known as color blindness is a real issue we must take into consideration in the design process. I have seen some companies respond that they have tested all their operators for color blindness, well they may have tested for red/green issues but there are other color deficiencies which are difficult or there is no solid test for.
The initial program to address many of these issues was raised by the ASMTM Consortium a Honeywell sponsored Research Program, unfortunately, word of mouth was the initial communication, not the actual documents because for a long period of time they were restricted as Consortium propriety. This word of mouth allowed a lot of new bad practices to evolve and when operators were presented with these new graphics they perceived them as inferior and in many ways, they were. It is taking a long time to get the true message and the facts out that address the Human Factor and Ergonomic issues associated with HMI design.
One of the big factors supporting the ASM graphics was the ability of a graphics project to demonstrate a good ROI and see a measurable performance improvement for an operator addressing an Abnormal Situation. This information about what led to this success was not communicated with the initial verbal release. Many vendors applied their own spin on the issue and produced me to solutions which were never based on the Research findings.
In an attempt to correct this Situation a few of us released the High Performance HMI Handbook which shared some of the concepts, later the ASM Consortium finally released their research findings but a little too late as the industry had now adopted the research and was doing new research but maybe not with the same integrity as the previous studies but they came up with alternative solutions which have just created more confusion and more stress for operators who are not getting the promised rewards of changing from their black backgrounds and bright colors. They were comfortable sitting in the dark watching these glowing figures change, while their eyes become fatigued over 12 hours of this and their circadian clocks stopped and they exposed themselves to health issues.
I have witnessed some very poor attempts to implement the High Performance and ASM graphics solutions all of these poor attempts have something in common, they often result in what we call blob graphics with poor contrast and operators find it difficult to identify what is going on in normal operations. The solution never is based on a hierarchy proposed by ASM and the ISA Standard SP101 it is just a redraw of the current level 3 graphics, no level 1 or level2 which is where the power of HP HMI graphics is focused. The graphics are like their traditional graphics lots of numbers without any context.
HP-HMI should illustrate if the PV is within the process operating range and how close the PV is to the alarm setpoints, the direction the value is going is sometimes important is it going up or down. In some cases we use objects like the traditional temperature bulb we are all used to for taking temperatures, this is a useful graphical way to illustrate all this data, and throwing a number next to it when it is outside operating limits provides two important advantages it makes this object stand out from the ones that are operating within defined limits and it also provides more insight for an operator who has to correct that value, during change the operators really like to have the numbers when making moves.
In the processing industry we traditionally show the temperatures of column and typically six or more PV’s are displayed inside the column, unfortunately, these values are only useful if the operator has memorized what is good, to get around this issue designers add an alarm point with these values and if the PV deviates into the alarm area the value is highlighted by a bright color to capture the operator’s attention. This, unfortunately, is late in the game and it would have been better to never get into the abnormal operating range and correct the problems such as a hot spot or a cold section by seeing the deviation during normal operations.
We achieve this by using the temperature bulb and laying it horizontally inside the vessel and joining all the temperature PV’s together with a line, hence, producing a temperature profile that will very easily visually show any deviation from normal which is calibrated to be a straight line. Using these kinds of techniques allows the operator to adjust from being just reactive to alarms to be pro-active in addressing Process Values (PV) as soon as the deviate outside of given operating ranges, hence, saving money and delivering the promised ROI. Today, many of our manufacturing plants live in abnormal operating areas and are not well controlled and avoid abnormal situations as evidenced by the number and duration of alarms that are active on a day-to-day basis.
High-Performance HMI has by its title sent a message to industry that we can do things better, unfortunately, this is only achieved by a more thorough understanding of the principles and practices that are being promoted by UCDS Inc.