Despite an increasing number of alternatives, the UK PLC market continues to thrive according to trade organisation Gambica, despite competition from IPCs. Just why this is, and the direction of the market is considered here by Mitsubishi Electric’s PLC Product Manager Hugh Tasker.
Over recent years there has been some blurring of the technologies, with each incorporating some of the features of the other. PLCs can now include functions ranging from embedded web servers to plug-in PC modules and C-Controllers. Furthermore, integrated MES modules allow PLCs to link directly to higher level reporting systems. Used with HMIs, PLCs also provide a very PC-like environment for SCADA and other visualisation applications. The latest generation of PLC platforms are also further extending the functionality they offer. Modules include embedded robot controllers and AI for flexible learning and intelligent decisions making.
PLCs offer proven reliability in applications where operating life may exceed ten years. The manufacturers also provide simple and straightforward upgrade paths. System integrators serving utilities and transport infrastructure have customers calling for longer lives. PLCs with product lifetime support of up to 15 years are becoming commonplace. In contrast PC hardware is rarely used for more than a few years.
UK PLC market
There are applications where only a PLC is viable, and others where an IPC is the correct decision. It depends on price, size and functionality, but there is also a huge overlap of applications. Both cope well with IoT/IIOT.
Machine builders producing standard machines can select a PLC, PC or custom designed controller. In contrast, OEMs and SIs who are adapting or customising individual machines have different needs. They frequently report they find it easier to configure PLCs to meet those differing user needs.
There are many other reasons why the appeal of the PLC endures. The issue of cyber security continues to grow. Many users are still reluctant to put what they see as more vulnerable PC hardware into critical automation systems. Perhaps that view is unfair as there have also been high-profile cyber-attacks and viruses targeting PLC software.
The bespoke operating environment of the PLC may offer protection through unfamiliarity compared to PC based control. However, it would be naïve to think that ‘security through obscurity’ would deter a determined hacker with the correct backing.
Both UK PLC market and IPC technologies will continue to develop and evolve. The debate of which will come to dominate is perhaps a blind alley. Far more important is to define the application requirements and then look at each technology on merit. The focus should be on implementing the best solution for the individual task. Will one prevail over the other? Probably not. A more likely scenario is the market will develop with both technologies working alongside each other.