Legacy controls systems face obsolescence issues as their underlying hardware and software ages. At a power plant, two control systems experienced this when their programming nodes - aging PCs running obsolete operating systems - were at risk of failure. Virtualizing the programming nodes solved this by hosting the legacy software in virtual machines, extending the life of the control systems cost effectively. This approach could help virtualize entire legacy SCADA systems for advantages like easy migration and hardware redundancy.

1. Legacy Controls Systems &Virtualization
April 2015 by Jerome-Axel Cain

2. Controls Systems Obsolescence
 An inevitable phenomenon with 2 possible main origins
— (i) Failure of the Controls System itself
• High failure rate of critical parts (chassis, processors, I/O & communications modules...)
• Lack of spare parts
• Lack of OEM support
• No expertise available anymore
— (ii) Failure of the Programming Platform/Node
• Aging/failure of the platform physical host (PC)
• Aging of the Operating System of the physical host (Windows XP)
 Failure (i) can be postponed almost indefinitely as long as:
— System remains functional and reliable
— Spare parts inventory is adequate and/or can be replenished
— Troubleshooting expertise is on-hand
— See NORPAK (1960-2014) at the Colorado Plant
 Failure (ii) might go un-noticed until it’s too late:
— Failure remains undetected until programming change is attempted (infrequent occurrence)
— Programming software might not run on current/newer operating Systems
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3. Controls Systems Obsolescence
 At Colorado Energy Nations, failure (ii) presented itself twice recently:
— Boiler 1-2-4 Combustion Controls
• Honeywell S9000 9100e Programmable Logic Controllers
• Functional & reliable, spare parts OK, expertise available BUT …
• Programming node (Multipro) was a 10 year old PC running Windows XP showing signs of imminent failure
• Windows XP was not commercially available anymore with purchase of a new PC
— Boiler 4-5 CEMS System
• Upgrade of RegPerfect Windows 2003 server because of ongoing RAID partial hard drive failures
• RegPerfect machine was CEMS PLCs programming node as well
• New RegPerfect Windows 2008 machine could not run Rockwell’s RSLogix5000 v13 programming software for CEMS PLCs
 In each case , 2 possible solutions:
— Upgrade of the Controls System itself
• Boiler 1-2-4 PLCs: $500k
• Boiler 4-5 CEMS: $350K
— Virtualization of the Programming Node
• Boiler 1-2-4 PLCs: through free version of VMware vSphere application
• Boiler 4-5 CEMS: through licensed version of VMware Workstation 9
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4. Programming Node Virtualization
 Boiler 1-2-4 Combustion Controls: networked approach
— Relies on the free version of VMware vSphere application which comprises:
• VMware® vCenter Server: the central point for configuring, provisioning, and managing virtualized IT environments. This piece
of software was installed on a dedicated remote server-class machine of our Controls Network.
• VMware® vSphere Client An interface that allows users to connect remotely to vCenter Server or ESX/ESXi from any
Windows PC. This piece of software was installed on several Controls Network PCs.
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-contains a Windows XP Virtual Machine with PLC programming software installed
-VM can be accessed remotely from any PC with vSphere Client
NB: VM requires a valid Windows XP license
-contains the vSphere Client
-accesses the Windows XP Virtual Machine
-Can edit PLC logic online or download logic to PLC

5. Programming Node Virtualization
 Boiler 4-5 CEMS System: local approach
— Relies on a licensed version of VMware Workstation 9:
• Installed locally on the new Windows 2008 Server RegPerfect machine
• Hosts a Windows 2003 Server VM (using license info from the old server)
• Local only access to the VM (not over the network)
• Sole purpose is to edit PLC logic online or download new logic to PLC
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6. Conclusions
 Useful life of 2 important PLC systems extended:
— For several years
— At minimal cost vs. price of full PLC upgrades
• $500 for the purchase of used rack server for VM Server
• $300 for the VMware Workstation 9 license
 A somewhat hidden issue:
— CEMS vendor (Teledyne Monitor Labs)
• At first unaware of legacy PLC programming issue after server upgrade
• Now proposes our VM solution to customers to avoid PLC hardware upgrades
 An approach that can be applied further:
— Possible virtualization of entire legacy SCADA systems offers multiple advantages:
• Easy migration with full version of VMware vSphere
• Hardware redundancy at the VM server level
• No more reliance on old PCs that can fail at any time
• Rebuilding of SCADA server / client / historian takes minutes in VM environment vs days in non-VM environment
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