Advanced control as operations support
By Allan Kern, P.E.
In operating plants, process engineers, also known as production or operation engineers, are usually heavily engaged in day-to-day operations support. They are more likely to be found in their hard hats, in ad hoc meetings, or working with operators than sitting at computer terminals. Their job description typically involves a good understanding of process economics, process constraints, and taking care of the equipment in their charge.
I am often surprised at how little process engineers and control engineers know about each other’s jobs, especially as they share the same underlying goal of process optimization. Today’s control engineers are often more occupied with the health of the control system than the state of the process. And process engineers often do not realize that a modern control system is a flexible and powerful tool—more like a robotic transformer than a pump—that can be brought to bear on a wide range of operating issues.
As control systems have modernized, control engineers have moved away from operation support and into a wide range of control system support, information technology, and reporting activities. Now industry needs to backfill the control engineering role that is more focused on applying the control system than supporting it. Leaving this role unfilled handicaps the operating team and neglects the automation potential of a modern distributed control system.
Process control and automation constitutes a core competency in the process industries. To meet modern manufacturing needs in safety, reliability, and agility, an operating plant must maintain a level of in-house control and automation capability that can serve as a ready resource and regular contributor to the operating team.
That is easier said than done. The loss of traditional control engineering know-how due to downsizing and retirement has long been lamented. But I think the problem is due to management decisions and industry trends as much as structural factors. Huge resources have gone into multivariable control, which unfortunately has failed to deliver the kind of automation success and operating agility that the process industries should be shooting for.
Multivariable control has probably moved industry farther away from effective operation support. Outsourcing means that resources have flowed out of the company, while more practical advanced control know-how has dramatically diminished from neglect and resource starvation. Multivariable control performance routinely undershoots expectations, and is likely to continue that way, based on its own emerging structural limitations. And the large controllers now deployed in industry often act as obstacles to agility, rather than as solutions, even as they continue to take a bite out of available support resources.
The recent era has left industry with control engineers who are quite skilled in control system support, but weak in operation support. Industry can address this by shifting a number of strategies:
- Control engineers should know process economics, process constraints, and the opportunities to improve them, just like process engineers. They should work as a team, not be strangers.
- Skilled control engineers should focus on supporting the operating team, not the control system or multivariable control.
- Many control system support activities lend themselves well to outsourcing. Outsource these activities, not advanced control.
- Traditional advanced regulatory control (ARC), which includes basic techniques, such as feedforward and adaptive gain, as well as more sophisticated solutions, such as custom programs and sequential controls, is where the best automation opportunities often reside. ARC took a back seat to multivariable control long ago, but it may be time to put ARC back in the driver’s seat.
- Advanced control resources should be used to build in-house ARC competency and a “can-do” automation culture of agility, targeted solutions, and incremental successes, rather than a monolithic strategy.
Process control and automation in general (not multivariable control in particular) is the key technology of our era when it comes to process improvement of many kinds. It is a core competency of the process industries and warrants involved management and effective resource allocation. Industry should commit to building a higher level of in-house competency and manufacturing agility as a strategy to take process control and automation to a higher level of success in industry.