Trust: Set it, forget it - choose to operate more closed-loop controls

Think Again: Since the earliest pages of Control Engineering in the mid-1950s, engineers have argued fervently about the merits of closed-loop versus open-loop control. Please, set up closed-loop controls where possible and let them work their magic.

06/01/2008


ONLINE extra

Two questions and related links, click here or scroll down.

Since the earliest pages of Control Engineering in the mid-1950s, engineers have argued fervently about the merits of closed-loop versus open-loop control. Please, set up closed-loop controls where possible and let them work their magic (which is what closed-loop control is, to those who don’t know or don’t think about what’s inside the box.)

Why do we need to close more loops? Demographics. Remember the skills gap in the news? There aren’t enough people being trained, the world over, to fill future technology requirements… as we do things right now .

As necessity is the mother of invention (thanks, Plato), we need to engineer more for autonomous operations where it makes sense. If there are fewer engineers and technicians around to design, operate, maintain, and upgrade complex equipment, more designs must be elegant and intelligent enough to operate on their own.

Trust the control loop:

  • Measure. Take the right measurement with the right sensors for the application;

  • Decide. Make a smart decision, consistently, using logic (hardware and software) to apply historical knowledge, rooted in wisdom, able to anticipate changing application needs; and

  • Actuate. Valves, motors, pumps, hydraulics, pneumatics, and other motive forces activate the process to make it go where it should go.

And then repeat, ensuring that networks reliably move messages around the loop, and human-machine interfaces, where needed, reassure humans that things are going just fine.

When the loop is closed, no human intervention is needed. With an open loop, at one or more points, a human intervenes. If we’re going to have fewer humans with enough training, we need to close more loops. And keep it simple.

That is easier said than done, of course, with the current technology installed in most plants. That is why, with your help, we explain (online, in print, and in person), how to better design, select, apply, commission, use, maintain, and upgrade controls, instrumentation, and automation systems worldwide.

Challenges increase as legacy systems meet newer, blended technologies that distribute and embed control loops closer to the process. Sometimes one box can integrate multiple elements needed for closed-loop control, which can be faster, without communication lag time… and more difficult to see. Standards help designs be more understandable, modular, reusable, flexible, scalable, and interoperable.

Fortunately, many automation vendors, original equipment manufacturers, system integrators, and end users increasingly “get it.” It’s all about putting more trust in elegant closed-loop control—the ability to design it, apply it, set it, and forget it.

MHoske@cfemedia.com


ONLINE extra - two questions, related links

I have two Think Again questions for you:
-Do people around your place understand this? I have a lot of hope that engineering “magic” can fill the skills gap.
-What are your experiences?
Please use the comment tools below to continue this discussion.
Also see:

Closing the Skills Gap


Global Manufacturing Reality Check


More interoperability, less effort





No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2015 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
2016 Product of the Year; Diagnose bearing failures; Asset performance management; Testing dust collector performance measures
Safety for 18 years, warehouse maintenance tips, Ethernet and the IIoT, GAMS 2016 recap
2016 Engineering Leaders Under 40; Future vision: Where is manufacturing headed?; Electrical distribution, redefined
SCADA at the junction, Managing risk through maintenance, Moving at the speed of data
Safety at every angle, Big Data's impact on operations, bridging the skills gap
The digital oilfield: Utilizing Big Data can yield big savings; Virtualization a real solution; Tracking SIS performance
Applying network redundancy; Overcoming loop tuning challenges; PID control and networks
Driving motor efficiency; Preventing arc flash in mission critical facilities; Integrating alternative power and existing electrical systems
Package boilers; Natural gas infrared heating; Thermal treasure; Standby generation; Natural gas supports green efforts

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
This article collection contains several articles on the vital role of plant safety and offers advice on best practices.
This article collection contains several articles on the Industrial Internet of Things (IIoT) and how it is transforming manufacturing.
This article collection contains several articles on strategic maintenance and understanding all the parts of your plant.
click me