No longer satisfied with control screens crowded with data, pulp and paper mills are seeking simpler user interfaces to provide real "information"

Improved Information Interfacing Turns Operators into Effective Process Managers

By H. Pierce Rumph

We wanted to create a consistent graphic user interface (GUI) for every operator, independent of the process, computing platform, or control system vendor," says the process control manager of a large southern market pulp mill, summing up the paper industry's need to improve operator access and usability of process information. "Our goal was to develop a common graphic style and navigational methodology in every control room, right across the facility."

The mill has now standardized the graphic interface, presented to operators in all control rooms, by using a virtual graphic overlay. An on-screen control bar (Figure 1) provides quick and intuitive access to navigation, information, and interactive functions throughout the control systems. This modern man-machine interface (MMI) also removes control screen clutter by highlighting only essential information, while keeping the remaining screen data in the background until needed.

"In today's business environment we expect a lot more of our operators," says Stan Causey, power and recovery superintendent at Riverwood International's coated board mill in Macon, Ga. "So, more than ever, we must focus on maximizing their effectiveness."

CHANGING ROLE OF OPERATORS. Before the introduction of modern automation technology, the process operator was an artisan whose personal control of the process influenced everything from kappa number at the digester and jet-wire ratio on the paper machine to product runnability on the customer's bag line, box converter, or printing press. Although that personal feel is still useful, much of the lower-level monitoring and control functions have now been assumed by the process control systems.

Figure 1: "Control bars" provide fast, intuitive access to navigation and information functions throughout a control system.

This transition is not unique to the paper industry; it has been evolving in all the major process industries worldwide. As a result, the need for routine operator interaction with the process has decreased. In turn, management is making fewer operators responsible for more process areas.

At the same time, supervisory control and data acquisition (SCADA) systems now provide operators with higher level information (e.g., SPC charts, trend plots, environmental calculations, costs, etc.), enabling the operator to function at a more strategic level, optimizing process operations and synchronizing them with other processes in the mill.

Riverwood's Macon mill has experienced this operator evolution, which began with a large mill control system modernization in the early 1990s. "When we began the modernization project," says Causey, "we had everything from 1960s vintage panel boards and pneumatic gauges to the latest Honeywell TDC-3000 distributed control system (DCS)." So operators functioned differently in the various control rooms.

The mill ultimately upgraded to the TDC-3000 DCS controls throughout the facility and chose a graphic user interface called "CyberBAR," supplied by Orion CEM (Atlanta, Ga.), to simplify operational interface. Orion CEM also performed all the control system engineering and installation in the mill's utilities department.

Riverwood power management provides a good example of the operator's changing role in the Macon mill. "We buy about half of our power," says Causey, "and in the summer months our power rate literally changes in real-time. So we rely on our operators to control the overall cost of power to the mill."

During the summer, between 3:00 p.m. and 8:00 p.m., power pricing varies as a function of overall demand. Utility operators follow the real-time power cost on their displays and at certain pricing 'switch points' (i.e. in dollars/MWh), they take corrective action such as shutting down non-critical lines or generating more power internally. "This is only one example," adds Causey. "The operator's job is changing throughout the whole corporation."

Using higher level information, presented clearly and consistently, a "new" process operator is emerging-one who will control the process to achieve the highest levels of quality, efficiency, and productivity, while still meeting environmental standards. The new process operator has become a process manager, enabled by essential process, quality, production, and environmental information that is presented in a clear, timely, and actionable manner. In this position, the process operator is rapidly evolving into another "knowledge worker" in the mill. Therefore, the goal today is not to replace the operators with automation, but to allow them to be more effective in their new roles.

CREATING CONFUSED OPERATORS. Mill E&I and process engineering groups spend much of their time making additions to DCS displays, with the result that a typical DCS display is woefully crowded with data. When overcrowding becomes intolerable, another display is created. As a result, the operator's interface to the process has continued to become more cluttered and complex. The question now is how operators are to sort out those "vital few" pieces of essential data from the "trivial many" pieces of lesser importance.

A complete redo is required, but in today's downsized environment, overworked process control departments don't have the time for strategic ergonomic changes, so they only make new additions as requested. Screen clutter is a serious operational problem in most mills.

Figure 2: "Picture-in-picture" displays show key process trends along with process graphic, process video, and quality information.

Figure 3: Simple icons show the information available, describing operations throughout the process graphic, which is shown below the control bar.

Figure 4: Tabular data is always shown above the control bar, with interactive graphics shown below.

Riverwood addresses this issue through judicious use of icons and special displays. For example, operators can call up process operating procedures with a finger touch or mouse click. "Just touch the 'Book' icon on the process' display and up pops the critical operator instructions," adds Causey.

Riverwood operators also make daily use of real-time trends, and critical variables (e.g., scrubber flow and differential pressure, both boiler environmental controls) are trended automatically. The last two hours are shown in a two-inch "picture-in-picture" (PIP) frame, when the appropriate process graphic appears on the larger screen (Figure 2). That same PIP technique is used to show critical variables on all processes in the department.

"It's an excellent way to reduce screen clutter," adds Causey. "If you clutter the screens, as most mills do, the operator can't distinguish the important activities from the non-important ones and efficiency suffers."

Also, years of observation demonstrate that most computer user interfaces don't adhere to accepted human factors, principles, and guidelines. Thus, the introduction of new computer control technology, intended to improve operator performance, may actually degrade it, particularly as new alphanumerics, process elements, and control features relentlessly creep onto the operator screens.

There are many examples of "panel board replacement" projects in which the new control systems required more operator activity and provided less process visibility, resulting in less efficient operations overall. Add this to increased safety requirements, greater process complexity, new environmental alarms, reports, and displays, and you have higher operator stress levels that will surely reduce the overall effectiveness of mill operations. The industry is thus overdue for a reengineering of operator interfaces.

"We focused heavily on the operator interface," says Causey, "since we wanted it to be clear and intuitive with a consistent graphic style (Figure 3), just as Microsoft Windows now does for office computers."

Almost all operator activities are performed through their CRT-based displays, which contain both graphics and alphanumerics (Figure 4). The material is presented in many forms, including numbers, letters, documents and drawings, spreadsheets, photographs, illustrations, video clips, sound bites, arrays, charts, and animated graphics. By definition, screen size is insufficient to handle the ever-increasing amount of data. Complimenting the displays, operator input devices also vary, and include keyboard, touch screen, light pen, trackball, mouse, joystick, function keys, touch tablets, and voice.

Through all of this maze, operators must efficiently navigate within a set of different databases, each with its own type of information and design, to gain the knowledge needed to make sound and timely decisions. It's an increasingly awesome responsibility for the average operator.

The burden can actually increase as operators are empowered with more significant tools. For example, during the 1980s, as part of the Total Quality initiatives, "statistical quality control" (SQC) became part of the quality arsenal in most mills. Later in the 1980s, SQC concepts moved from the labs onto the process floor, and the resulting statistical process control (SPC) found wide acceptance. New SPC concepts such as "process capability, control charting, and SPC rules" became part of the control room vernacular. SPC modules became integral to control systems. Control charts were plotted and viewed by the operators. "SPC alarms" were added to the already crowded alarm fields on the control screens.

Like other useful tools, SPC has expanded to the point where operators want no part of control charts because they are just other pieces of data to analyze in an already overstuffed brain. To deal with that, new systems hide the charts, and background computing continually analyzes them, providing an alarm when an SPC violation is detected. An analysis page for the operator can also be accessed that explains the violation and indicates possible causes. Based on this information, an operator can call up instructions that show probable causes and corrective actions. All of this arrives instantaneously to facilitate timely operator action.

As operators become knowledge workers, they must have help acquiring and managing the knowledge. Success of this effort depends on the culture and organization of the mill, but also on the operator delivery mechanisms. Some of these include groupware, messaging, web browsers, document management, search and retrieval, data mining, visualization, push technology, intelligent agents, and expert systems. Of course, not all of these may be applicable to today's process control requirements, but who knows what tomorrow will bring. Mill management should be addressing such issues.

For the most part, pulp and paper corporations have not developed human factor guidelines applied to visual display units, so MMI systems engineering is still in its infancy. Exact monitoring requirements are often poorly understood by the operations staff, and, as a result, operators try to monitor everything. Attrition and rotation of operations personnel further compounds the problem.

SOME RECOMMENDATIONS. Human factor considerations are most effective when they are addressed at the front end of a project while design flexibility is high and costs are minimal. The graphic user interface displays should be modeled after the process being controlled, and that similarity should be easily perceived, interpreted, and evaluated by the operator. Displays must be designed to support specific operator tasks. Novice operators may need to use additional tools, such as online procedures and manuals, which should be available through a context-sensitive part of the interface.

Interface design should also consider two key components in relating to the operator-an information component and an interaction component-so that operators can visually separate the "reading" and the "doing" areas. Related information should be grouped and properly ordered for easier operator access and comprehension.

Operators also need a "quick look" display of the overall state of a process, as defined by a set of previously determined critical parameters. For example, a field of green process symbols could mean that "everything's okay," while a red one here and there might call for operator attention.

A common graphic style guide can dramatically improve mill operations through the following benefits

• Increased operator efficiency, speed and accuracy
• Improved decision-making
• Increased responsiveness
• Higher quality
• Reduced duplication
• Better training and lower training costs
• Reduced lost time and equipment losses
• Improved system safety.

The need for a systematic and consistent graphic style guide cannot be overemphasized. A consistent and uncluttered graphic user interface will result in easier operator training, better operator performance, improved process operations, and big financial benefits to the mill. If a mill hasn't already thought about a graphic style guide for its facility, a multidisciplinary task force is the way to begin. This is an elegantly simple way to reduce the complexity and clutter in control room displays and sharply increase the effectiveness of operators.

Operator display guidelines

Every mill should have a graphic style guide to be followed in the design of all control room displays. Based on experience in many mills, some useful guidelines include the following:

1. Display partitioning: Organize screen information into functional groups to help the user visually perceive that the screen is structured in
a logical format. Minimize or (preferably) eliminate overlapping windows.

2. Grouping: Use a logical method for grouping-e.g. group according to functionality and importance to the operator's task at hand.

3. Display density: Provide enough information for the specific operator's task without cluttering the screen. Display content should be influenced by someone who knows the process and its operations.

4. Framing: Some mode of consistency and standardization should be adopted for all the elements on all screens (e.g., Microsoft Windows). Similar guidance information (e.g., icons) should be found on every screen.

5. Paging: Whenever possible, all data related to the user's current transaction should be on one display frame. When not possible, standard navigational tools should be used to toggle between frames.

6. Color: Color should be used as a formatting aid to assist in structuring a screen. Color use should be consistent with traditional expectations (e.g., green = "okay", yellow = "caution"). Colors should be consistent within a frame, from frame to frame, and with other color codes used in the control room.

7. Voice: Spoken messages should be used when more message flexibility is needed than a tonal signal can convey.

8. Animation: Animation should be used to show transitions, not continuous operations. Continuous animation is distracting.

9. Icons: Icons are used to improve the user's comprehension of and interaction with a database management system. They are preferable to abbreviated text, and they simplify user dialog.