Basic process control systems—also known as Level 2 in the Purdue Enterprise Reference Architecture (PERA)—has formed the basis for successful process manufacturing for decades. During that time, industry has witnessed several technological revolutions that have each produced more accurate, precise and faster process control and, consequently, better product quality and throughput. Innovations have moved from the mechanical to the electrical and on to the computational. Currently, the trend in automation has moved innovation further up the architecture, with mostly incremental changes at Level 2.
Meanwhile, the Open Process Automation Forum (OPAF), a forum of The Open Group, has shifted the focus to stress the need for standardization at Level 2 to help reduce lifecycle costs. What, then, can industry expect from this level in the automation architecture in the future? How should end users prepare?
The roots of control innovation
Many forms of mechanical devices have been used for process control over the past century as innovations occurred slowly and methodically. When computer processing emerged in automation during the 1960s, process controls could be easily changed, repurposed and made to interact with other controls. A decade later, networking technology allowed greatly increased data exchange between controllers and operators. Compute power and memory increased, as well. Both trends continued through the 1980s and 1990s and extended into field devices.
In the past decade, industry witnessed a greater emphasis on securing Level 2 control assets and reducing the labor needed to install, commission and maintain those assets. However, when it comes to the basic process control technology, not much has changed in that time.
This led to OPAF’s greater focus on standardization and lifecycle costs. The recent ARC Industry Forum in Orlando, Fla., dedicated several sessions to the topic. ARC analysts have written numerous reports and blog posts about it as well. Specifically, OPAF has zeroed in on standardizing systems for ISA95 Level 1 and Level 2 functions. These systems are basic inputs and outputs from field devices and regulatory control function block execution. ExxonMobil and other end-user companies envision automation systems with many more—but much smaller—process controllers. These smaller hardware devices would control as few as one or two loops each creating what are, in effect, microservices for process automation.
Members aren’t looking for technical innovations to revolutionize basic process control. All the technical innovations required to achieve their goals have been created. Instead, they want to transform the business aspect of automation by making it less costly to engineer, staff and update. In fact, much of the recent innovation we’ve seen from automation suppliers centers around reduced project and lifecycle costs rather than improving process control at Level 2, where it appears that all the opportunities have already been seized.
Parallels from Level 1
This parallels what has already occurred with process field devices. When you consider the valves and transmitters in your plant, they are pretty much commodity items. Each instrument manufacturer might have slightly different features and functionality, but their products will usually accomplish the goal. Configuring these devices once consumed a considerable amount of engineering time, but now end users just send the supplier their process data and receive a properly configured device in return. Plant technicians install it and it’s done.
The market is now taking a similar approach for Level 2 control. The value proposition on most field devices revolves around ease of configuration, ease of use, ease/cost of support and initial cost. All new value in the space is found in the software applications supervising the devices. The approach that OPAF is pursuing means there will be little to no intellectual property to safeguard at the control level, just like a transmitter today. Instead, critical information will be maintained at a higher level in the control strategy. An OPAF architecture would certainly enable suppliers to safely embed proprietary (and potentially superior) Level 2 control algorithms in products, but it is an open question whether they will focus on this level rather than higher-value applications such as model predictive control for multiple loops.
Given the trends above, ARC expects to see little change in the approach to control at Level 2. The proportional–integral–derivative (PID) algorithm has been “good enough” and will continue to do the job. Software innovations for control development and for advanced applications will likely become the main areas of automation innovation in what could be labeled as Level 2.5.
>>Mark Sen Gupta, [email protected], is research director of ARC Advisory Group. He has more than 25 years of expertise in process control, SCADA and IT applications with companies such as Mobay, Honeywell, Plant Automation Services (PAS), CygNet Software and Invensys. He holds bachelor’s and master’s degrees in electrical engineering from the Georgia Institute of Technology.
