Virtualisation, a computing approach that decouples hardware and software, is rapidly gaining traction in the traditionally conservative automation and control industry. With its roots in the information technology (IT) world, virtualisation was initially met with scepticism for industrial applications. But this has changed ‘big time’, largely driven by end user demands to reduce costs and make more efficient use of existing computing resources.
Today, most major automation suppliers support virtualisation in one form or another, predominantly for PC and/or server virtualisation. With virtualisation, a single computer can host multiple instances of the same, or different, software applications, as if each was running in its own dedicated computer. This is true regardless of the specific operating systems employed. In this manner, much of the hardware simply goes away, offering significant benefits over the lifecycle of an automation system. These benefits include reduced hardware and associated support costs, reduced space requirements, reduced electricity requirements (both to operate the computers and for the associated HVAC), and increased scalability.
Since these benefits clearly outweigh any perceived or actual risks associated with the technology, ARC Advisory Group believes that the trend will continue and, in fact, will accelerate as control system architectures evolve.
Virtualisation rapidly gaining traction in automation
Virtualisation of computing devices started in corporate IT departments and has now moved into the plants’ control system architectures. Historically, due to their conservative nature, control and automation departments were slow to adapt to the concept of virtualisation, which both requires an additional layer of specialised software, and concentrates (rather than distributes) processing power and applications. This created concerns over the impact of hardware failures on critical plant applications. However, rapid advancements in virtualisation software technology and extensive field experience have largely made these concerns go away.
In many cases, virtualisation was thrust upon automation departments and automation suppliers alike through corporate-level pressures to save costs at the operating companies. Initially, virtualisation was used solely at the operator interface level, where one server with several thin client terminals replaced several dedicated PCs. Once this use of virtualisation proved itself, many virtualised applications were implemented successfully at the operations management level. Today, it is common to see historians, engineering functions, and optimisation packages all running on one physical device rather than separate dedicated devices.
Virtualisation facilitates upgrades and expansions
Reducing the numbers of PCs and servers used for automation and supervisory applications can help reduce both capital and operating costs by reducing the number of computers required, reducing expensive control room and rack room space requirements, reducing energy consumption, and reducing maintenance and support requirements.
Virtualisation also saves costs during upgrades and expansions because the existing server can usually accommodate additional virtual machines (VMs). This allows new applications to be added without incremental hardware costs and without having to take the hardware offline, which could result in significant and costly production interruptions.
Virtual machines are highly portable, allowing software maintenance personnel to migrate them to different physical machines. This enables maintenance to be performed on the hardware without impacting production operations and loads to be balanced more efficiently across the physical infrastructure. Also, if a physical server fails, its VM can quickly be restarted on another system. This makes VMs a great solution for business continuity and disaster recovery.
Will the trend continue?
By now it should be apparent that much of the hardware in a control system has been gradually replaced by software through virtualisation and other techniques. The question is: ‘Will the trend continue and what hardware will be the next to go’?
ARC believes the virtualisation trend will continue. It is part of the larger trend in the automation and control industry in which less and less physical hardware is required; simply because software functionality is replacing physical devices across the control architecture. For example, in the last couple of years alone we have seen much of the physical I/O of both process automation systems and safety integrated systems move to largely software-based configurable I/O. In this case, one smart physical I/O board running software has replaced as many as 20 physical part-numbered I/O hardware boards.
Physical networks of Ethernet cables and switches are also being virtualised with virtual LANs or ‘VLANS’. So what is left to virtualise? At this point in time, even though the control functionality in large-scale process control systems is largely programmed in software, that control software still runs in purpose-built physical devices, often in redundant configurations.
Given the rapid pace of technology and the rapid acceptance of virtualisation techniques elsewhere in the system, it is anyone’s guess about how long this will last.
For more information contact Paul Miller, ARC Advisory Group, +1 781 471 1126, [email protected], www.arcweb.com
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