A couple of years ago, I was amazed to discover a conversation in Germany regarding PC-based control versus “old, proprietary PLCs”. Seeing that the conversation was in Germany, I assumed the “old” one to be Siemens and the new one was relative to CODESYS and companies such as Wago and perhaps Beckhoff. Then I just saw a conversation on LinkedIn where an American magazine evidently re-ran an old programmable automation controller (PAC) versus programmable logic controller (PLC). In both cases, the “old” PLC vendor rendered much of the argument moot by adopting PC-based technologies into their products.

The Open Process Automation Forum opened a new branch to the argument with the push for Software Defined Control Architecture. This is interesting. OPAF has progressed through definitions and standards—more on that in my next post. For this post, I’m reporting some news from, well, Germany, about an advance by a new company called Software Defined Automation. I wonder where this will lead us. It will be interesting. I have yet to see anything push Siemens and Rockwell off their thrones on the factory side or Emerson/Honeywell/Yokogawa/ABB on the process side. But, you never know. 

Munich-Based Software Defined Automation (SDA) and VMware Implement Real-Time Virtual Programmable Logic Controllers (vPLCs)

The execution of deterministic real-time control on virtualized edge servers in combination with a comprehensive vPLC management interface in the cloud is aimed to be a unique solution, enabling customers to improve productivity, utilization, and security while at the same time gain independence from vendor-specific hardware and silicon.

The SDA solution will help improve industrial automation with the full virtualization of PLC controls on the VMware Edge Compute Stack that supports virtual machines (VM) and containers running on conventional IT servers at the edge. The real-time control on a VM will commission, monitor and manage vPLC instances on servers located in factories. The virtual real-time controllers, which will be installed and managed by SDA at the edge, have already been shown to achieve deterministic control cycle times of <10ms.

Many recent innovations developed by the IT industry have not been adopted in the area of PLCs. Traditional PLC implementations in hardware are costly and lack scalability. Since the emergence of the standard IEC 61131-3 in the 1980s, PLC technology has advanced very gradually. Current trends improve the PLC’s memory and processing power while shrinking their size. Yet, the technology still relies on on-site monitored and individually programmed PLCs that must be taken out of operation in order to change the code – leading to operational downtime and reliability risks. This common practice is due to the lack of alternative technologies and tools that could reduce the software limitations of PLCs and free them from the need to being manually managed on-site by automation engineers.

Virtual machines and containers transform hardware systems into software systems, in which all elements run on local off-the-shelf IT infrastructure. The VMware Edge Compute Stack in combination with SDA’s vPLC management and monitoring services will enable improved security, reliability and resilience while allowing for intelligent and deterministic real-time responsiveness.

The vPLC solution aims to bring the benefits of cloud systems to the shopfloor, increase resilience and security, while preserving real-time capabilities.

The solution is based on a hybrid architecture between a cloud system and an industrial workload on the edge. The hardware resources located at the edge will be efficiently used with VMware’s Edge Compute Stack, which manages the resources according to each vPLC’s needs. SDA is working on extending this technology stack with a management system for fully virtualized PLCs based on CodeSys technology to incorporate the industrial control layer as a software. The management system will simultaneously hold virtual PLC twins in the cloud.

The offering can then help to generate value for all sorts of industry processes controlled by PLCs. Software-based PLC implementations will end up being more flexible, simplifying the delivery logistics and reducing software commissioning time. The vPLC’s runtime at the edge can be updated over the cloud via the SDA management console. vPLCs will be handled as IT workloads and state-of-the-art IT best practices are applied to bolster automation IT security. Furthermore, the integrated monitoring service ensures that allowed vPLC response time thresholds are not exceeded. 

Dr. Josef Waltl, CEO and co-founder of SDA, stated, “Today’s technological advances in software and cloud computing allow management of real-time control systems in a pure software fashion. The SDA vPLC service is able to meet sub 10ms performance, required for the many of industrial applications currently controlled by conventional PLCs.” 

Muneyb Minhazuddin, vice president of edge computing, VMware, notes, “The pandemic has shown how vulnerable manufacturers still are at the edge despite having implemented latest industry 4.0 and cloud technologies. It’s the last mile that is still dependent on human intervention and vendor hardware, yet it is a vital part of production process controls that needs to be addressed. Together with SDA, VMware Edge Compute Stack will help manufacturers optimize PLCs in a time of semiconductor shortages, enabling resiliency, flexibility and effectivity at the very heart of their edge operations.”

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