Changing times and requirements are placing new pressures on Distributed Control Systems to become more flexible and adaptable. ABB’s Luis Duran looks at two initiatives that are helping to facilitate the rapid development of systems with openness, security and interoperability at their heart.  

Although developed 40 years ago when Centralized Computer Control Systems of the time were too complex and costly for the plant environment, Distributed Control Systems (DCS) have not ceased to transform and evolve. Originally based on purpose built technologies that became what today we refer to as Operational Technology (OT), the need for more flexibility and demands from users for more options has seen them adopt commercial off-the-shelf technology (COTS), as well as Information Technology (IT) to link up previously isolated control elements.  

This desire to get more from their DCSs has not ceased and current users are looking for DCSs that are more open, expandable, and flexible. The response from manufacturers has been to increasingly move away from DCSs designed around dedicated and custom designed hardware with fixed functionalities, and towards a philosophy based on software. This has fundamentally changed the concept of the DCS, making it much more agile. This agility in turn has brought the prospects of plug and play components and helps free users from proprietary solutions.  

The introduction of COTS and the rise of the Internet and enhanced connectivity has revealed the lack of robust cybersecurity, particularly on early DCSs, driving changes in the way the DCS handles information and indeed how it works.   

Some major operators of DCSs also use them in different ways. For example, a pharmaceutical company wanting to expand production of a new drug will need to look for different ways to reconfigure equipment, with many elements requiring a high degree of modularity. Modular elements bring the ability to reconfigure production as needed without affecting core DCS applications.   

Modularity can also allow a more cost-effective deployment. A company may conceive a DCS as part of a large capital investment project but may still want to keep initial investment to a minimum while it proves the control concept. Increasing production over time, after the initial investments had started to produce revenue and taking advange of modern approach by copying infrastructure from one application to another thus allowing the user to manage capital costs and improve its investment strategies.  

More value from data  

The rise of the Industrial Internet of Things or IIoT has also highlighted the need to get value from information, such as sensor readings and production data, that is today largely trapped within the DCS. Most devices in the field communicate with the DCS using 4-20mA or 24V discreet, with the DCS converting the value into an indication of a parameter such as pressure or temperature. Devices have now become much smarter than they were 25-40 years ago and operate with a multitude of communications protocols that expand the information available in the field device.  

To realise the value of this information, it needs to be extracted from the DCS and made available to particular groups of users. Many of these will not be the traditional users of the DCS but rather will be accustomed to modern digital technologies and will expect the DCS to present information in ways more reminiscent of consumer devices such as tablets and smart phones.   

Similarly, some information will not be needed or used within the confinement of the DCS and could instead be made available in different ways.   

As communication technologies like wireless and 5G and smart digital devices such as sensors and motors become more common, the DCS needs to match and take advantage of their capabilities with a more digitalized, more open infrastructure. A standard way of communicating across multiple devices will allow technology to be integrated more seamlessly right across a manufacturing facility.   

In turn, the interoperability enabled by open communications allows system components to be integrated much more cost-effectively, allowing software to be uncoupled from hardware and allowing a move towards hardware agnosticism.   

User groups driving change   

Initiatives in both the EU and US are taking on board the need to access more information and make more efficient use of technology.   

Although users generally demand stable, reliable performance from control solutions, these same users are also driving fundamental change in DCS and have formed several industry groups to develop greater openness, security, and interoperability in DCS solutions.   

One of these groups is the Open Process Automation Forum (OPAF). The group, formed of end-user companies primarily in the oil and gas and chemical sectors, together with automation vendors such as ABB, aims to define a standards-based, open, secure and interoperable architecture that will set the pattern for future Process Automation Systems.   

OPAF aims to provide DCS users with easier access to leading-edge capabilities. Achieving this will allow best-in-class components to be integrated into a DCS, while preserving asset owners’ existing applications. The standard forms an open systems architecture to promote innovation and value creation. As a commercially viable standard, it meets the needs of multiple industries, and allows DCS users and suppliers to collaborate on new solutions.   

With its origins in Germany’s chemical industry, NAMUR is a global consortium of process industry end-user organizations that has defined an open architecture model known as NOA, for NAMUR Open Architecture. This architecture effectively separates out information that is less critical and that can be used for optimising the company’s facilities. It essentially creates a new maintenance and optimisation layer with separate access to information currently trapped in the DCS.   

NAMUR participates in standardisation bodies as part of its aim to helps member companies avoid wrong investments, gain early access to promising technology, and ensure technology standards meet users’ needs.  

Although both OPAF and NAMUR are trying to define a common communications interface and a common information model, they have adopted different approaches. OPAF is attempting to define a standard with guiding principles, with the goal of redesigning the DCS to make it more interoperable and simpler to upgrade.  

By contrast, NAMUR is trying to create a structure to work alongside the DCS to obtain the information needed, without fundamentally altering the way the DCS operates.  

Another initiative is Modular Automation, an industry-wide initiative effort that seeks to replace the concept of large, monolithic automation systems with a philosophy of more flexible modules that can be more easily combined in a system. The goal is to allow faster implementation of processes, an easier scaling of capacity and more rapid changeovers of product.  

Open standards essentially define how we can communicate with the range of different equipment within the plant. As standards become more digital and flexible, industries will want to choose between either OPAF or NAMUR, each of which adopts different ways for users to access their information.   

Some of the major industries pushing for more open standards include chemicals and pharmaceuticals, oil and gas refining and petrochemicals, pulp and paper, mining and metals and newer areas such as datacentres. All these industries are looking to more advanced technologies that can help them make best use of their capital investment and achieve the production they need as quickly as they can. They also need long term stability and lower TOTEX.   

Companies of all sizes are early adopters of these more flexible technologies, with smaller companies in particular benefitting from the modularity and the scalability they provide. Although change can often be difficult, open DCS standards are showing companies that they provide the data they need to allow them to be more efficient and compete more effectively, a factor of ever growing importance in the face of a challenging and increasingly unpredictable business climate.  

For more information, please contact: ABB Limited Affolternstrasse 44 Zurich 8050 Switzerland Tel: +65 (0)6773 5857 Email: susan.brownlow@ch.abb.com Web: https://www.abb.com

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