There's always more to see and focus on—especially when developing and improving human-machine interface (HMI) displays and screens to help operators understand their applications and make the process they control run better.
This was the main incentive behind the advanced interfaces, faceplates, tabs and other features designed, developed and implemented by Dave Sosulski, DCS systems coordinator, and his colleagues at Nutrien's Cory Potash plant in Saskatoon, Saskatchewan, Canada. The mine has 350 employees and produces about 800,000 metric tons of potash per year. Nutrien is reported to be the world's largest producer of crop inputs and services, and resulted from the merger of PotashCorp and Agrium at the beginning of this year.
"We wanted to update the pop ups and faceplate packages on our interfaces, so we're not just showing the faceplates but also more of the data points behind them," said Sosulski. "Using human-centered design (HCD) for our interfaces is more scientific, objective and driven to a certain purpose. We simply want to present data to our operators that will enable them to self-train, drill down faster and more efficiently, and make better, faster decisions."
Sosulski presented "An Advanced Human-Centered Design (HCD) Analog Input Faceplate (with Trending Events and Diagnostics)" this week at the Emerson Global Users Exchange in San Antonio.
Despite the potential benefits of HCD for interfaces, Sosulski recommended that operators and other users be consulted on redesigns, and eased into accepting and using the new displays and their enhanced capabilities. The main faceplate features on interfaces at Nutrient's Cory mine include high and low alarms, operational ranges, hover help, events, equipment trips, details page, operator notes and trips.
"HCD means increased productivity with easy transition to new faceplates, more information to make decisions, and preserving information across shifts," added Sosulski. "HCD also means that simplified information can be understood faster by allowing operators to see what's going on at a glance, and recognizing patterns instead of reading and interpreting values."
For example, when seeking to improve an analog input (AI) faceplate, Sosulski explained it's useful to follow the example of an analog thermometer. "Everyone understands a thermometer, so an AI faceplate should also be obvious and work well," said Sosulski. "Some starting points for HCD in our case included not cutting off the device description line at the top, defining if the middle arm was high or low, and indicating when the alarm came in. Now, we have a three-line device description that includes location, so the operators and technicians know where to go to fix it."
To help smooth operator acceptance of their new HCD-based faceplates, Sosulski added they were allowed to use either the new-look or old-look interfaces for a while before the new-look became the default and the old-look was removed. "We also added metric units, but kept the British units, and showed both for a year," he said. "As a result, the operators were able to accept the new units in their own time, and weren't forced to do it. So, when metric became the default it wasn't a problem, and many didn't even notice."
Beyond three-line descriptions and flexible units, Sosulski reported that Nutrien's new-look interfaces include dark green backgrounds voted on by the operators, alarm priorities and times, and features that coincidentally turned out to be very similar to Emerson's DeltaV Live interfaces.
"We had a veteran operator who knew what all the production numbers meant, but he couldn't train others how to do it, and never passed down that know-how," said Sosulski. "As a result, we learned that, if an alarm indicates where a process shouldn't be, then we also need to show where the process should be. That's why we present the operating range as a white vertical bar, and added trip points as a black vertical bar with a yellow outline, so it would show up against the green background. Good HCD can show what's going on without numbers."
Sosulski added that that Nutrien's trip bar also shows what other devices may trip as a result of the first event, and users can hover over it to show what happened earlier. Likewise, the new interfaces have tabs with shortcuts users can employ, and switch quickly between data points, rather than repeatedly drilling down and backing out.
"Tabs let users go right to the data they need without leaving the faceplate," he added. "The Help tab lets them self-train about updates and descriptions. The Alarm tab includes both device and area alarms. The Details tab has I/O diagnostics and module diagnostics with operating limits and trips. It indicates any problems in succession from the workstation to the controller to the card to the I/O. And, the Events tab is cool because it shows the last 100 events by day, week or month for all of us that spent too much of our careers trying to find out what happened on last night's shift. Now, the interface path is a lot easier, and people can see what's going on for themselves."