End users in the chemical and energy industries now must contend with and integrate multiple, proprietary systems in almost every process plant or facility. With industrial control systems, end users experience several major pain points: (1) lack of interoperability and inability to reuse their control applications between systems from different suppliers; (2) excess cost during system upgrades due to close couplings between components; and (3) barriers to introduction of new technology. These pain points result in elevated capital costs on new projects and high total cost of ownership through the asset lifecycle, especially in operation and maintenance.
To address these pain points, the Open Group Open Process Automation Forum (OPAF) of The Open Group, an international forum of end users, system integrators, suppliers, academic institutions and standards organizations, is working to develop the specifications for open-architecture-based process control systems. OPAF’s goal is to enable more open and modular systems that support integration of best-in-class components.
This architecture will provide both configuration and application portability across components from different suppliers, thereby reducing system capital cost and total cost of ownership. The vision is a standards-based, open, secure and interoperable process control architecture that lowers the cost of control system upgrades and replacements, removes barriers to technology insertion, and has adaptable cybersecurity designed in.
This article, which is an adapted, updated version of a keynote presentation at Yokogawa’s “Y-NOW 2020: DX Solutions for Tomorrow” event, outlines the progress of the Open Process Automation initiative, the Open Process Automation Standard (O-PAS), and the status of industry prototyping. It also briefly addresses key end-user issues such as cybersecurity and long-term control system migration.
Digital Transformation
In meeting the challenges presented by the “new normal” business environment, the chemical industry rapidly accelerated the adoption of digital transformation. Many years of planning and implementation were consolidated into a matter of months. As digital transformation efforts continue, it is clear that the role of process control systems will loom large in the industry.
Digital transformation requires the low-cost implementation of change — which is the ability to make rapid, iterative and data-driven innovations in plant operations — at a fraction of the cost previously possible. This demands overcoming the restrictions to innovation created by closed, proprietary systems. Since its origin in the 1970s, process control architecture has continued to include significant proprietary hardware and software elements despite the wide adoption of a variety of de facto and industry standards.
Major global industrial and chemical companies are collaborating with leading process automation suppliers and system integrators to accelerate a revolutionary change in automation through the adoption of O-PAS, a standard of The Open Group. O-PAS provides a critical standards framework to address these issues and many more.
O-PAS Standard Update
The focus of O-PAS is to reduce the cost of control system upgrades and replacements and enable increased value generation by removing barriers to inserting technology. OPAF also plans to achieve adaptable cybersecurity that is designed-in to our systems. Figure 1 shows the scope of this activity; it includes the distributed control system (DCS), programmable logic controllers (PLCs), input/output (I/O) modules associated with the DCS and PLCs, and the layer of supervisory control above the DCS. Out-of-scope are field devices and communications to them, the safety instrumented system (SIS), and the business systems that are shown above.
Figure 1. The initiative focuses on the five elements within the box.
The vision for the solution to the business problem is to transition from closed, proprietary control systems to a standards-based, secure and interoperable open process automation (OPA) architecture. Figure 2 depicts the reference architecture we would like to achieve. In contrast to the current state-of-the-art, which is based on the Purdue reference model and its 1970s-vintage computer-integrated-manufacturing heritage, we now see an architecture that more closely resembles an Internet and information technology (IT) style reference. Its architecture has three basic distinguishing characteristics: an edge device, an industry-standards-based communication network, and a supervisory computing platform.
We refer to the edge device as a distributed control node (DCN). It features configurable I/O, the first touch of computing, and interfaces to existing equipment, such as those depicted by the blue boxes in the figure.
The second distinguishing characteristic, the industry-standards-based communications network, is the O-PAS connectivity framework.
The third distinguishing characteristic is the on-premise supervisory type of computing platform that takes advantage of technologies already used in IT and telecommunications. The reason for the on-premise location is to provide the availability and low latency required for the types of applications that will run here. The OPA reference architecture supports communications to all sorts of field devices, both wired and wireless. It also provides data pathways to either a company's internal, higher-level compute capabilities or public or private Cloud platforms.
Technical Standard
The standards that drive the OPA vision are the product of the OPAF. OPAF was founded in 2016 and, at present, has 102 member organizations. These include 22 operating companies representing five different industry vertical sectors, six of the seven major control system vendors, including Yokogawa, which is a very important contributor to this effort, and a large number of hardware/software suppliers and systems integrators.
In OPAF, the development of the technical standard is occurring in parallel with efforts to address the business ecosystem required for the successful commercialization of the vision. We also are bringing forth the conformance certification process in phase with the development of the technical standard. When we set forth the design for the standard in 2017, we defined three steps in the initial development versions, with each taking approximately a year to a year and a half. Version One (V1) addresses interoperability, Version Two (V2) configuration portability, and Version Three (V3) application portability across the full spectrum of the business problems that we want to solve.
Figure 2. The distributed control nodes, connectivity framework and on-premise computing are key distinguishing characteristics. Click here to view the PDF, which provides a better view.
We refer to the concept as a “standard of standards,” which means that if an existing standard is fit for purpose, the idea is to incorporate it into the OPA standard. Figure 3 shows how we intend to leverage some current standards — for instance, ISA 95 (IEC 62264) for technical architecture, and ISA 99 (IEC 62443) for cybersecurity. OPAF also references OPC UA and others in this standard of standards.
In June, OPAF published O-PAS V2.1. (Again, the theme for V2 is “configuration portability.”) This includes a specification for the file formats for import and export between various software products and where that file format leverages the AutomationML standard. OPC UA’s information models comprise a key portion of the data interface that enables interoperability. The specification describes how to do alarming, provides for a basic set of function blocks that are at the root of industrial control systems, and details how O-PAS leverages the IEC 61499 and IEC 61131 standards. It also broaches new territory, i.e., the physical realization of the DCN that we call the “physical platform.” Part 7 of the O-PAS standard specifies the physical platform.
In addition to the technical work, the business and enterprise working groups are addressing how to promote industry adoption, manufacturing of products, and deployment of those products by end users. We held an Industry Adoption Workshop on October 29, 2020 and an End User Caucus on July 20, 2021 where O-PAS V3 contents were discussed to understand end-user priorities and needs. The business and enterprise architecture working groups are assisting in defining requirements for O-PAS V3. The conformance working group is very active starting-up the first phase, which we refer to as “Wave One” for conformance certification. It addresses Part 5, which is the specification for systems management, as well as Part 4, the O-PAS connectivity framework. Meanwhile, the technical working group is busy defining the V3 requirements, where the key themes are going to be application portability and orchestration technology.
Industry Prototypes
Several operating companies now are conducting prototype tests of O-PAS-based systems. Figure 4 summarizes the three major OPA system building projects that ExxonMobil has completed or has in process. The proof-of-concept was a demonstration against a simulated plant. The prototype was an O-PAS-based system in Clinton, N.J., that controlled an actual pilot plant. It is a hydrocarbon-containing unit for catalyst control operating at 660°F and 1,200 psi with 130 I/O points. Lockheed Martin and the Wood Group served as systems integrators. ExxonMobil found that the prototype, like the proof-of-concept before it, demonstrated the quality attributes of interoperability, interchangeability, configuration portability, and application software portability.
Now, the company has built a testbed facility in The Woodlands, Texas, just up the road from ExxonMobil’s campus. Yokogawa is the prime systems integrator for this testbed; it is the staging location for a set of industry field trials. ExxonMobil also has established a collaboration partnership with seven other operating companies, as listed in the figure. They are sharing information about their findings as each company begins to conduct its prototyping or testbed activities.
Figure 3. O-PAS leverages a number of relevant existing standards.
Other operating companies also are working on prototypes. For instance, BASF has produced a portable demonstration of an O-PAS-based system that can be exhibited at trade shows. It includes a water tank, two heaters, four coolers and 12 valves. The key results BASF has reported are conformance to the OPA standard and demonstration of the Namur Module Type Package and Namur Open Architecture concepts.
In addition, Georgia Pacific has just completed what it refers to as a “demo display board,” which is a portable instantiation of an O-PAS-based system. Siemens is the systems integrator. Saudi Aramco is building an OPA testbed in Dhahran with Schneider Electric as the system integrator. In addition, Petronas has announced plans to build an OPA testbed in Malaysia.
Migration To O-PAS
Naturally, control system end users wish to avoid completely replacing their existing systems and, instead, phase-in open architecture. That’s completely consistent with the low-cost implementation of change OPAF considers to be a cornerstone.
As with any significant technology transformation, it will take time. We view migration in terms of ten- and 20-year horizons. Within ten years, we expect many existing facilities to incorporate O-PAS-based systems as they replace components. This will result in hybrid systems with mixtures of existing DCS and PLC technologies and O-PAS-compliant ones. Naturally, the initial uptake will comprise innovators and early adopters; their systems should go far in building credibility for O-PAS. In addition, some of the supplier companies that are investing very heavily in the OPA concept, Yokogawa for example, will be at the leading edge of that transformation.
Over the same timeframe, we expect a healthy share of new installations to deploy O-PAS-compliant systems. Those systems will make immediate use of the Industrial Internet of Things and other technologies emerging today. Their architectures will exemplify the OPA reference and will resemble far less the hardware-defined segmented arrangements such as the Purdue model.
Within 20 years, we expect industrial control systems to look much more like the OPA reference architecture engines — in contrast to the current DCS and PLC configurations — and to embody the OPA business ecosystem.
Integral Cybersecurity
A key O-PAS principle is that, as technology transformation occurs, no compromises will be made in terms of requirements for reliability, availability and cybersecurity. For cybersecurity, O-PAS, Part 2 leverages the IEC 62443 standard. The conductivity framework of the O-PAS standard that uses OPC UA takes full advantage of certificate-based message authentication and role-based access control as fundamental technologies for cybersecurity. The IEC 62443 concepts involving zones and conduits to segment a network, limit the scope of failure and provide adjustable layers of security. In the Yokogawa testbed, ExxonMobil has incorporated technologies such as the latest firewall from Palo Alto Networks and is experimenting with anomaly detection inside the control network.
A key point of the O-PAS standard is to define the interfaces to achieve the quality attributes of interoperability, interchangeability and portability, particularly for the end user’s software applications. We consider cybersecurity a foundation for this.
Figure 4. Work has progressed from proof of concept to prototype on pilot plant and now to testbed to support field trials. Click here to view a PDF, which provides a larger version.
Compelling Benefits
Open process automation offers advantages to both end users and suppliers. Among other things, end users will gain:
• easier application reuse;
• designed-in safety and security;
• elimination of system integration issues; and
• reduced total cost of ownership.
Meanwhile, suppliers will get benefits including:
• access to new markets and customers; and
• efficiency improvements from dropping non-differentiated products.
A key to success is a demand for change from a critical mass of end users. Based on the efforts to date and how far we have progressed in terms of commercialization, OPAF feels that we are nearing an inflection point when end users begin requiring O-PAS conformance in their bid specifications and suppliers announce roadmaps for O-PAS-conforming products.
DON BARTUSIAK, who recently retired after 33 years with ExxonMobil, is president of Collaborative Systems Integration, Austin, Texas, and co-chair of The Open Process Automation Forum. Email him at [email protected].
