Recent Trends Shape Future of Distributed Control Systems
By Barry Young
Several trends have already impacted the distributed control systems (DCS) market and are likely to continue to do so over the next few years. These include both product- and technology-related trends and general industry trends.
The DCS input/output (I/O) subsystem is responsible for inputting hundreds or often thousands of different process measurements and other inputs into the system, and outputting control signals to a large number of valves, actuators, motors and other plant final control elements. I/O represents one of the most significant parts of the DCS, and traditionally, a significant cost element. However, DCS suppliers are working to reduce both the cost and the complexity of their I/O by incorporating more intelligence and programmability into the devices.
Today, in a greenfield plant, most of the I/O supplied is on some type of bus network. Brownfield plants are also installing more bus I/O. However, with the large installed base of traditional 4-20mA I/O, the transition is very slow. Major expansions or revamps in brownfield plants consider bus I/O when the sensors and final control elements are also part of the project.
There is also a growing trend towards adding more wireless I/O and associated field devices, particularly for process and equipment monitoring applications.
As the lines between automation and information technology (IT) begin to blur with increased use of commercial off-the-shelf (COTS) technology, the network infrastructure of the DCS and the network architecture for plant information become increasingly intertwined. End users now often rely on the expertise of suppliers for consulting to set up these networks in a safe and secure manner.
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DCS suppliers started incorporating server virtualization a few years ago. Common uses of this technology include engineering development and for simulating automation in training. Virtualization is not appropriate for all parts of the DCS. Sometimes, dedicated hardware will perform a given task better than a virtual server. A good example is the real-time process controller in a DCS, where speed, determinism and high reliability are major design considerations for the operation and safety of the plant. On the other hand, a virtual server performing many applications on one box can be a good choice for “offline” applications such as control configuration, simulations and training.
Just as people today find it hard to live without their smartphones in daily life, process operators and production supervisors have increasing reliance on the ability to “access data anywhere, anytime” to perform their job functions. DCS suppliers address this trend by supplying tablet technology for roving operators and using smartphones for alerts and condition monitoring. This trend towards increasing mobility will grow in importance in the coming years.
Move to the cloud
There has been much talk in the industry about developments underway to move selected DCS applications “to the cloud,” a reference to moving applications to remote, Internet (public)- or intranet (private)-based servers. However, the control automation industry is very conservative by nature, and for the time being this is just talk. ARC believes that, ultimately, selected DCS applications are likely to move to private, and in some cases, even public “clouds”; but for now, end users are wary.
More process units these days are built and delivered on skids, rather than built in situ. As a result, DCSs are showing up on the skids when they arrive at the plant or mill. Unless there has been good coordination upfront between the equipment supplier and the user’s automation team, the skid-mounted DCS technology can be different than the desired system for the plant. Heterogeneous DCS solutions require additional communication interfaces and significant increases in engineering services.
Barry Young, firstname.lastname@example.org, is principal analyst at ARC Advisory Group in Dedham, Mass. ARC will be focusing on several of these important trends at the upcoming ARC World Industry Forum www.arcweb.com in Orlando, Florida, Feb. 6-9, 2012.