By: Kobus Vermeulen - Direct Sales Executive, Process Automation at Schneider Electric

As sayings go, there are few as apt as “the sum of its parts”.  And it certainly holds at its truest when it comes to technology and particularly process plants. Today, many plant control systems remain stable whilst the hardware infrastructure around it is toppling.

Indeed, ageing servers, unsupported operating systems (OSs), and increasing maintenance complexity are quietly introducing risk into otherwise stable DCS (distributed control systems) environments.

And for operators, this creates an oh-so-familiar rinse and repeat cycle; refresh hardware to stay supported, manage downtime during upgrades, and do so again every few years. 

Fortunately, there is a more pragmatic way forward, virtualising the control system environment, therefore, decoupling the DCS from the constraints of physical hardware and allowing it to flourish in a virtualised word.

Ageing infrastructure’s hidden risk

As mentioned, many plants today are running DCS on legacy server platforms tied to outdated operating systems (OSs) and hardware. While these systems may still function, the risks are compounding, leading to hardware failure as sourcing like-for-like replacements becomes increasingly difficult. 

At the same time, unsupported OSs fall behind on critical security updates, exposing control environments to evolving cyber threats.

More importantly, these environments tend to be operationally fragile. A single server failure,  whether hosting an HMI (human machine interface), historian, or application layer, can result in a loss of view, leaving operators without visibility into live processes. 

Decoupling control 

Instead of tying each DCS function to a specific physical server, engineering workstations, HMIs, historians and application servers are hosted as virtual machines (VMs).

Each VM encapsulates the full runtime environment including OS, control software and configurations, making it portable and hardware-agnostic. The underlying server infrastructure then becomes interchangeable.

Practically, this means hardware refreshes no longer require system rebuilds or downtime. If a server approaches end-of-life (EoL) or shows signs of failure, workloads can simply be moved to another host, often without interrupting operations.

Indeed, live migration enables running systems to be moved between servers without interruption, allowing maintenance or hardware replacement to take place without impacting operators. 

Furthermore, it allows plants to move from hardware-driven lifecycle management to software-driven planning. Upgrades to control software or OSs can also be scheduled based on operational priorities, not dictated by failing infrastructure.

Building a low-risk, high-return roadmap

One of the most common concerns among current plant owners is the perceived cost and disruption of moving to a virtualised environment. In reality, the transition can be structured to minimise both.

Here, a phased approach typically begins with assessment and planning, followed by deploying the virtualisation platform in parallel with the existing system. Initial migrations focus on low-risk components, allowing teams to validate performance and stability without impacting production.

Only then - once confidence is established - will operator-facing systems be transitioned:

• The most fragile and high-impact components are prioritised. HMI and application servers are often ideal starting points, as they are both critical to operations and highly exposed to hardware failure.
• Historians and engineering environments also present strong early candidates. Virtualising these components reduces recovery complexity and secures critical data and configuration assets, while allowing extensive testing through VM snapshots before any cutover.
• Equally important is ensuring that network architecture, storage performance, and host capacity are correctly designed to support virtual workloads, particularly for operator-facing systems where latency and responsiveness are critical.

In the end, decoupling DCS from ageing infrastructure, plants can reduce risk, improve availability, and regain control over their lifecycle strategy. 

Virtualising control systems enables organisations  to modernise without disruption, decoupling it from the hardware obsolescence trap whilst offering a smarter way to sustain performance for years to come.