Don’t overlook training: Efficiency, safety require operators know how to interact with HMIs before alarms occur
A key component in the efficiency—indeed the success—of any human-machine or operator interface is adequate training. No automation system can function effectively unless it is properly run, and no system operator can be effective without sufficient training.
As HMIs proliferate, manufacturers have begun to recognize the value of training and its influence on operator interfaces. Given the same people and the same interfaces, system performance will improve if operators are well-trained initially and attend a training refresher at least annually. Because abnormal situations, thankfully, don’t happen all that often, skills, much like those of an airline pilot, need to be sharpened regularly.
How does an operator know how to respond properly when that group of alarms that really means something comes in, asked Pete Henderson, senior product manager, UniSim product line, Honeywell. “Without training, without getting into a simulator like that pilot does, an operator likely will not be ready to respond quickly and appropriately.”
Henderson sees a lot of activity going on in the training arena these days. “Manufacturers are willing to invest more in training,” he said, “to prepare operators to take advantage of new features and graphics.”
Making a commitment to training
Training systems may be applied to a number of situations. They may be used to instruct new operators, to provide regular refreshers for existing workers, or to offer guidance for everyone when system and process changes occur. “Maybe the company only needs to provide training on the advanced control unit that was recently added to the plant,” said Henderson. “On the other hand, at a new facility, the entire workforce might be trained for an initial start-up.”
Training curricula typically are developed by the system vendor in conjunction with the facility. The system might be PC-based, it may consist of a classroom-led process familiarization, or it may be one-on-one instructor-led sessions on procedural operations. Training varies in type and degree, but in nearly all cases systems are customized for the individual facility. “It may simply be a modification of a standard configuration,” said Henderson, “but it typically reflects actual plant conditions. For example, operators need to be taught process fundamentals, but they also have to know how to interact with plant components, with the operating graphics; they need to have a way to practice their skills. Training systems help them do that.”
Effective training programs thoroughly examine and assess operators using software-based tools. Dynamic simulation of the process and its associated equipment combined with regulatory logic and safety system controls let operators work with a virtual plant. When an operator sits down at a training console, in many cases he is unable to tell the simulated system from the real thing. The system has been equipped with numbers similar to what the operator would see in an actual plant situation; the controls are the same as those in the plant.
Instructor-based systems extend the training process, and provide a more comprehensive way to assess competency. They have the added benefit of personal observations to determine how well the operators are performing. For instance, an instructor can subjectively assess an operator’s ability to interact with the work station. How efficiently does he manage the displays? Is he responding appropriately to an incident? Is he methodical in the approach used? Does he relate appropriately to the graphics displayed?
Training simulation provides a facility with the tools it needs for both evaluating and validating operator effectiveness with the HMI. Workstation training may include the entire plant automation system or only a portion. “Scalable solutions allow plants to train in the way that suits them best,” said Henderson. “Today, we see a lot of interest in ways to measure key operating variables against some basis of criteria,” said Henderson. “When a challenge is presented to an operator, he is supposed to know how to react to whatever upset has occurred. He should know how to avoid the trip that would result from gradually deteriorating operating conditions. Assessment tools are designed to measure how well the operator can maintain a number of variables within a target range.”
During the training process, an operator may be asked to respond to an alarm, to identify where a tag is, to access the correct display, and to examine the variables around an alarm. When a new system or module is installed, or a change made to a process, operators then can practice on the simulator to become familiar with the DCS, the alarms, and the graphics before he goes out into the plant.
Henderson described a hypothetical training example: “Consider a scenario in which a pump trips and an alarm comes in. The operator sees and acknowledges the alarm on the HMI alarm display and quickly navigates to the relevant operating graphic. While the pump flow diminishes, some of the key operating variables around that pump failure are disturbed, and the operator’s test score starts to fall. As he gathers his thoughts, he reacts to the scenario—perhaps he starts a spare pump or takes the system to a safe point of operation. His score then recovers as the system assesses his ability to meet production targets and quality criteria. As the exercise reaches its completion, the alarms start to return to normal and the operator acknowledges it.”
All these events, from initial malfunction to final acknowledgment, are captured and reported. Event logs document operator performance. The operator can see his scores, what he did well and where he may have been able to do better. An instructor or supervisor then can act as a coach by observing the operator’s behavior, reviewing the simulator reports and offering suggestions to improve his skills and his performance.
Overall, the objective should be to train operators and gauge their competence. To develop an appropriate training program and schedule, the instructor must understand plant operating objectives and map these to training solutions and competencies. Operators need to be trained to detect incidents before they happen. They must know how to recover safely and quickly return the operation to normal should an incident occur.
Facility and trainer should form a lifelong partnership, Henderson recommends. “And that partnership should begin, if possible, with the initial system and startup and continue on through the changes and modifications that are made,” he went on. “They should work together to analyze training objectives and develop a system that truly reflects actual plant behavior. Remember that no plant is static. Improvements and changes are constant and they typically are made in areas that are easiest to change: namely, the automation systems. Companies often find that the easiest way to optimize plant production is to modify the procedures or control systems that are running the plant. Those changes can and should be updated for operators promptly on a training simulator.”
Training benefits correspond closely to the degree of effort expended, noted Henderson. “A company needs to stay on top of training,” he said, “and a training solution needs to be implemented no matter what the situation. Like anything else, operator skills go out of date quickly because changes are made in most operations fairly frequently. Skills become stale if they are not used often. Plants that are highly automated present many opportunities for operator skills to atrophy.”
Training helps boost operator performance and HMI interaction because it provides the opportunity for operators to make mistakes and improve skills. In the confusion that often surrounds an incident, the operator’s actions need to be reflexive to be optimally efficient. The only way to do that is to practice the scenarios of potential abnormal situations.
“Sometimes the best lessons,” said Henderson, “are those learned through mistakes…but no one can afford to make those mistakes in the plant. However, a training simulator creates an environment where the operator can safely learn from his mistakes. It is experiential learning, which leads to the best knowledge retention.”
And, in turn, to more efficient HMI performance.
Information for this article was provided by Pete Henderson, senior product manager, Honeywell UniSim product line, Honeywell.