In a successful industrial manufacturing environment, data is king. During two sessions at the Rockwell Automation RSTechED conference this week in Orlando, Fla., attendees learned both how displaying and representing operating data to process operators should be done to maximize operator awareness and performance, and how proper data collection, organization, and record keeping make life easier for companies with regulatory compliance responsibilities.
During the session "How to Improve Plant Operations Through Better HMI Graphics," Dave Board, Rockwell Automation commercial manager, provided key insights into how to design effective human-machine interface screens for plant operators, noting "Who wants to be responsible for designing an HMI graphic that can lead to confusion, cause eye fatigue, and cause operators to make mistakes?"
So, Board said, good situational awareness for operators means "being aware of what is happening around you, understanding what the information means to you now, and understanding what that information means to you in the future. It also relates to the goals and objectives of a specific job or function."
Board said designers and engineers form in their heads a different mental model of the process than do the operators. "So by understanding how operators select and use goals, designers can better understand how information is perceived," he stated. "Without understanding the user's goals on situational awareness, the information presented has no meaning."
Board explained how to apply situational awareness (SA) terminology to HMI graphics. "Level 1 SA is a process and instrumentation diagram (P&ID) representation with raw numbers on a screen," he said. "Level 2 SA provides the operator with the relevant information they need to understand how the plant is operating. Level 3 SA provides trending data so that the operator can see how it has /performed and how it will perform." Level 2 and Level 3 SA, Board said, reinforce the operator's mental model of the plant or process.
Board made it clear that despite the wonderful and imaginative, 3D color graphics available to designers today, they have no place in a best practices list for industrial operator displays. "Use gray background, vessels and pipes in low contrasting grey," he said. "High contrasting color objects strain the eyes and cause fatigue. Warm colors—the reds, orange, and yellow—especially when flashing, draw the operators attention to them. Color should be used for abnormal plant conditions only." In like fashion, there should be little or no movement of objects that cause unnecessary distractions.
Board is a big fan of analog status indicators to help interpret data. "The brain interprets analog more quickly than a number," he said. "We should provide a pointer to a scale, provide a clear indication of the normal working range, and clearly show upper and lower limits." With an analog display, the operator can easily see where the value is as well as what it is. And he can easily see rates of change. "The key operating parameters should be trending on screen, not requiring the operator to click to show them.' Board stated.. "And radar plot are good for easy monitoring of multiple, but related variables."
Good Data = Safer Food
In a second RSTechED session entitled "Hillshire Brands: Manufacturing Intelligence Key Ingredient in Food Safety Modernization Act Compliance," attendees learned that the completeness, integrity and historical availability of production data in the food processing industry for product traceability is of critical importance, given a heightened consumer awareness of inspection failures and product recalls in recent years.
Most of the activity is driven by the Food Safety Modernization Act (FSMA), explained Ian Tooke, director of consulting at Grantek Systems, which works with Hillshire on these issues. "In 2011, the CDC estimated that in the U.S, more than 48 million people got sick as a result of food-borne illness," Tooke explained. "Not all of that is attributable the manufacturing process, but annually 3,000 die from it." Tooke further estimated the hit to the U.S. economy at $7 billion per year, not including the potential impact on a particular company's brand equity.