More accessible and easier to read, high performance graphics are quickly adopted by process manufacturers
The human machine interface (HMI) graphic world came into being about 30 years ago with basic interfaces displayed in black and white. A year or two later, color graphic interfaces were introduced, starting a trend that would last for decades. The latest industry trends have moved away from the “fruit salad” graphics, yet many companies and end users fear moving away from these colorful graphics.
What are High Performance Graphics?
High performance graphics move the displays to a monotone gray world, where the background and objects like tanks are a neutral gray color. Graphics with animations use white for running and dark gray or black for stopped (see Figure 2). All alarms and transition states then have bright noticeable colors and specific shapes to help carry the importance of an alarm through to the user. The International Society of Automation (ISA) started the HMI standards for high performance graphics in 2009, with a notable article about adoption of the standard by Bill Hollifield in late 2012. The standard (ANSI/ISA 101.01–2015) is slowly being adopted in manufacturing.
There are a few reasons moving to high performance graphics is a good choice. One reason is the typical red and green colors used historically for running and stopped are not clearly visible to people who are colorblind. One in 12 men and one in 200 women are colorblind, leaving a portion of the workforce unable to see these colors. Additionally, red and green colors are often confusing because some facilities and industries will use green as safe and red as running, causing additional confusion for people moving between facilities or industries.
Another reason high performance graphics are preferable is the standard allows an operator to glance at a screen and know if something is wrong. Even from a distance it becomes clear if something is off, on or in trouble because only these items have color.
Quickly Assessing the Process
High performance graphics make it easy for the operator to assess what is happening in the process at a glance. A common way to do this in high performance HMIs is to show a bar chart of the process variable (PV) right on the overview screen. The bar chart shows the normal operating range of the variable, so that the operator can know where the value is in the range and if it is approaching the limits. Another way to show data at a glance is to show a real-time trend of the process variable. This allows the operator to quickly see how a variable is trending so that he or she can react before the process becomes critical.
Alarms are more manageable as well. Often an operator can become overwhelmed by alarms. By using icons and colors to indicate the severity of an alarm, an operator can quickly decide which alarms are the most important to react to.
With common grayscale graphics, any change in color quickly draws the eye to the alarm on the screen.
Making the Transition
Matrix Technologies has helped several clients in the process industries make the transition to high performance graphics. The transition to high performance graphics usually happens by a forced move rather than a chosen one. Several HMI and supervisory control and data acquisition (SCADA) platforms now have high performance graphics libraries. These graphics are designed to meet the high performance standards. This comes up in discussions in the design phase of the project and is often met with uncertainty and trepidation, which proves to be unfounded. In talking about it with employees from the plant floor to maintenance to engineering and above, people are usually very concerned or resistant to change. Within two days of the new system implementation, the operators are saying they find the new system to be helpful in the day-to-day operations and it is actually making them more effective.
Some customers are willing to embrace the neutral background, but they don’t think they can live without the red and green (running and stopped) color scheme they have always used. Early editions of PlantPAx included the ability to change the colors of the pre-built objects, but in the last couple of years support of the color change tool has been discontinued. This is forcing the customer to fully make the transition to high performance colors.
Overhauling an HMI can be costly, but when upgrades to the systems are being made it is worth the investment to make the transition to high performance graphics. Using pre-developed graphic libraries makes the transition easier, more timely and cost effective because the color coding is already built into the object library.
For more information, read The High Performance HMI Handbook http://a.co/be8U8Qk.
Matrix Technologies is one of the largest independent process design, industrial automation engineering, and manufacturing operations management companies in North America. To learn more about process design capabilities and manufacturing process control solutions, contact Dave Blaida, PE, CEP & President.
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Multidiscipline Engineering – Process Design