"Poor basic control performance is rampant, including poor tuning and poorly maintained valves," says Bill Hollifield, principal alarm management and HMI consultant at PAS Inc. and co-author with Hector Perez of the High-Performance HMI Handbook. "This is like sending a race car driver out on the track with lousy brakes. Neither the operator nor the process can perform well with poor basic control. Fortunately, many alarm systems are being fixed, and alarm management has become well-accepted. However, alarms are a small part of the overall operator HMI, and so high-performance HMIs based on new principles for creating screens are needed to correct poor, widespread and ingrained HMI practices. A proper HMI increases operators' situation awareness and their ability to detect and successfully resolve abnormal situations."
See Also: The Eye for Plant Operators' Eyes
Hollifield adds that PAS recently worked with the Electric Power Research Institute to proof-test these high-performance HMI concepts at a large coal-fired power plant using several operators and a full simulator. "The tested HMI included proper hierarchy and embedded knowledge, and we found that operator results were better when handling significant abnormal situations," adds Hollifield. "Besides showing useful information instead of just raw data, displays should be designed in this hierarchy that provides progressive exposure of detail. Displays designed from a stack of schematic designs will not have this. They'll be 'flat' like a computer hard disk with one folder for all the files. This doesn't provide optimum situation awareness and control. A four-level hierarchy, including operation overview, unit control, unit detail and support and diagnostics displays, is desired. For example, Figure 2 is an operation overview from a large power plant. We often hear, 'But it doesn't look like a power plant!' Correct! Does your automobile instrument panel look like a diagram of your engine? The display is designed so important abnormal conditions and alarms stand out clearly." [A whitepaper by PAS on these high-performance HMI principles and the EPRI project is located at http://tinyurl.com/a8tdjln.]
Holistic Human Factors
Besides improving HMIs and displays, enhancing performance also means assisting the physical eyeballs viewing those screens—especially when their owners' attention falters and they get tired. Limiting work hours and potentially dangerous fatigue has long been mandated for airline pilots, first responders, truck drivers and other professions, but it's not as well-known or established in many process operations—where many managers and operators rely on too many overtime hours and consecutive workdays.
See Also: User interfaces should empower operators
To remedy these dangerous situations, the U.S. Dept. of Transportation's Pipeline and Hazardous Materials Safety Administration's latest rules took effect in September 2012, and they require pipeline operators to use display graphics that employ human-factor designs; reduce operator fatigue by limiting consecutive hours and days worked to a more normal weekly schedule; establish thorough alarm procedures; document and learn from incidents; and pay fines up to $1 million or more per violation, according to Ian Nimmo, president of User Centered Design Services Inc..
"More process facilities are investing in control room management (CRM) and human-factor principles, and they're taking countermeasures against fatigue, such as deploying 24/7-style chairs, brighter lighting and better temperature control, providing exercise equipment and enforcing regular breaks," explains Nimmo. "They're also monitoring hours worked by operators and calculating the relative risks of incidents, which is going to force some to hire more staff. Besides providing more human-factors graphics, process managers also need to conduct a risk assessment to make sure their operators can handle the number of alarms they're going to get. Then, they need to take a holistic CRM approach, evaluate the roles and responsibilities of their operators and define exactly what they're supposed to do in specific situations, including normal and abnormal operations and in emergencies."
Curing Computer Clutter
While software and computers of all types are indispensable to manufacturing in general and process control and automation in particular, the downside is an increasingly impenetrable jungle of software applications and packages that don't share data fast enough or allow operators to access information they need to make crucial decisions. Fortunately, some solutions are coordinating different types of software and bringing them into more manageable formats.