Will PLCs (OT) Follow The Server Virtualization Trend From IT?

Imagine an industrial plant being operated through the cloud. This concept isn’t too far from the future given the current trends of servers migrating to cloud computing. Programmable logic controllers (PLCs) are on track to follow the same evolution of server virtualization; it’s only a matter of time and I’ll explain why. 

IT versus OT

Most people are aware of how much information technology (IT) connects our devices to the cloud for the purposes of work or play. In the industrial sector, there’s a parallel that exists which pertains to how machinery communicates. Operational technology (OT) is designed to manage, monitor, and control industrial processes related to the physical equipment in industrial facilities. An OT system connects to the local programmable logic controllers (PLC), sensors, motors, drive controllers, and a variety of other devices. 

PLCs have traditionally been local

A vital component of many industrial operations is the programmable logic controllers which are located close to the machine. The central controller handles the processing inputs such as digital and analog inputs, counters, speed monitors, and more. It also calculates the flow control and process algorithms (PID, motion control) and interfaces with an array of SCADA technology, human-machine interfaces (HMI), and high-level database integration tools. 

IT is server-based and can be anywhere in the world

The key player in information technology is a server–the central controller in the disparate PC network. Looking broadly, each website or cell phone app is hosted or communicates with a server. For IT in the workplace, most internal tools are either cloud-based or server-based. In the span of 15 years, servers have transitioned from on-site to the cloud (or 3rd party dedicated server units).

Advances in technology

Industrial welding robots.

Server advancements: virtualization

The shift for servers has taken them from single computer operating systems to multiple server images running on a single piece of hardware. This is called virtualization or running on a hypervisor and it’s typically what cloud-based systems are comprised of. 

PLC advances towards server concept

The traditional PLC hardware used to be bound by many wires and field terminal extensions. The modern advances have allowed PLCs to have fewer I/O connections and instead become simple CPU units installed to a cabinet. Similar to the IT space, PLCs uses network-based protocols to speak with distributed I/O modules. That not only simplifies the wiring but when done in parallel with the other advancements in PLCs, whether it’s improvements on speed, memory, number of cores, or connectivity, they become comparable to a server.

PLCs are lagging server technology

Given the similarities between the two technologies, it appears that servers are having a quicker progression. An argument can be made that PLC’s have lagged in their evolution because they require long-term support and guarantees for detailed end-of-life planning. 

Looking at the trend of PLCs shifting to the networks, the PLC is on track to follow the same evolution of server virtualization. Could a PLC exist on the cloud? PLCs are already being moved to the network, so an additional step to the cloud isn’t as far-fetched. Imagine an industrial plant wasn’t required to upgrade their outdated PLC but instead they pay a service fee to a cloud computing company with the PLC image in a virtualization container. How reliable would this be? Current servers have reliability rates as high as 99.99%. 

In terms of security, most OT networks already have connections to the web and they operate using the same principles. Safety systems are currently run over wireless networks that had previously been thought impossible. Considering the simplicity and cost savings of not having to update PLCs and having the server industry moving in this direction, the question is: why not have PLCs follow the server virtualization trend?