Audi has implemented virtual PLCs at one of its plants, with the aim of reducing the variety and number of hardware devices needed and converting applications to run in software thus making production faster, more robust, and more flexible.

A key aim of the German car-maker Audi is to have stable and consistently available production facilities where it can build as many cars as possible. But to speed up the integration of innovations from the rapidly developing world of IT, and to optimize production continuously, this production needs to become more IT-oriented.

A major challenge for Audi is the wide variety of devices that it uses. To adapt production to increasing customer demand, more hardware devices must be installed. However, in recent years, delivery periods have become stretched. Often, updates have to be installed manually on the hardware devices and maintenance can be costly, but both are necessary to ensure cybersecurity. Power consumption is also high. As more hardware devices are installed, more power is consumed, affecting energy efficiency.

To meet these challenges, Audi realized that it needed to merge IT and OT in its production environments by virtualizing the shop floor. It has therefore created a new software-based infrastructure modeled on how data centers are implemented.

The lowest level of the infrastructure is always the same and lays the foundation for various applications. With its Edge Cloud 4 Production platform, Audi has transferred this principle to production and has revolutionized automation on its shop floor, including the use of virtual PLCs.

The platform has been created by a team of IT and OT specialists who’ve designed a private cloud infrastructure that covers all of the production requirements in a factory. Applications run in this cloud as software – including Siemens’ Simatic S7-1500V virtual PLC.

After some initial debate about how IT-based production should be designed, it quickly became clear that a large-scale concept was required. It took about three years to evaluate its feasibility and perform the necessary tests. This period was needed to define requirements, test conditions, and talk to the manufacturers of the necessary components. This way, the partners in the virtual PLC project were already benefitting from each other early on: Audi from Siemens’ expertise in the field of automation engineering, and Siemens from Audi’s feedback. The technologies also needed to be modified: for example, to establish the real-time capability of the lower-level infrastructure.

Software-driven factory automation is only feasible if suitable software-based controllers are available. Audi needed a virtual PLC that would be compatible with its Edge Cloud 4 Production platform and could be integrated into its existing automation environments.

“The virtual PLC represents a revolution in automation engineering and industry, making it possible to rethink a factory and its infrastructure,” says Sven Müller, project manager for Edge Cloud 4 Production at Audi.

The Simatic S7-1500V virtual PLC was first tested successfully in Audi’s production laboratory. Part of the line being used to produce Audi’s e-tron GT high-performance electric car at the company’s Böllinger Höfe plant in Neckarsulm was then chosen as suitable for the initial commissioning of the virtual PLC in a production environment. The line’s small-series manufacturing was ideal for testing the new technologies.

Working with Siemens, Audi performed tests at the plant to learn about the on-site setup and to discover if there were any challenges that might hamper the implementation. This cautious approach helped to increase employee acceptance. The growing number of successful tests boosted Audi’s confidence in the virtual PLC.

“Naturally, employees were initially skeptical and expressed reservations,” acknowledges Robin Fallmann, who is involved in production planning for automation engineering at Audi. “This was our motivation for making the rollout planning for the overall project as detailed and predictable as possible.”

Before commissioning the technology in a working production environment, there was a preparatory phase, lasting several months, during which servers were built, the network was planned, components were installed, and connections to the industrial edge were set up.

According to Pascal Schirmer, the member of the Edge Cloud 4 Production team who was mainly responsible for the initial implementation, the preparatory phase was successful because all of the participants had agreed on clear goals, and each of them had invested the time needed to achieve the agreed milestones on schedule. The experience will contribute to the implementation of subsequent rollouts, he adds.

Implementation

The virtual PLC was introduced in the spring of 2023. At the time, Audi was already starting to convert its first assembly plant to Edge Cloud 4 Production. The cloud went live in July 2023.

Preparations for implementing the virtual PLC started soon after that and required close collaboration between Audi, Siemens, and other technology partners. Since January 2024, two virtual PLCs have been deployed successfully on the e-tron GT axle assembly line in Audi’s Böllinger Höfe factory.

Although the conversion to IT-based shopfloor automation is a huge step, the site’s employees have hardly noticed the change. They continue to access all the functions that they know from hardware PLCs, as well as familiar user interfaces and tools. Thanks to compatibility with the Siemens TIA Portal platform, no other programs have needed to be written for the virtual PLC.

The uniform infrastructure ensures that all of the virtual applications operate on the same basis, allowing complete digital management. Activities can be conducted centrally or remotely. Management via the cloud production platform also enhances cybersecurity, because many of the previous attack vectors have been removed from the production environment.

Because the virtual PLC is downloaded as software and deployed via an industrial edge platform, the problems of extended delivery periods and the need to install hardware components have both been eliminated. Additional instances of the PLC can be downloaded if needed, and unnecessary instances can be uninstalled. This saves money and energy. Updates, and apps from industrial edge management, can also be rolled out quickly and easily plant-wide and on a remote basis.

In addition to the technological hurdles, many organizational challenges also needed to be overcome. Employees and management had to be won over to the concept of IT-based factory automation, the functionality of the virtual PLC had to be demonstrated, and responsibilities had to be assigned. An Edge Cloud 4 Production team was established that allowed IT experts to collaborate closely with OT specialists. Thanks to extensive testing at the plant and close alignment between the IT and OT teams, Audi and Siemens were able to commission the new technology relatively smoothly.

Just the start

The successful initial implementation of the virtual PLC is just the starting point. Over the next few years, both the virtual controller and the cloud-based infrastructure will continue to be developed, tested and rolled out further.

The priority in the coming months is to train employees at the Böllinger Höfe plant in the new technology. The first apps from Industrial Edge Management are also being rolled out and tested, including Siemens’ Sinec Traffic Analyser. The apps can be downloaded and used flexibly, and can be deleted later when they are no longer being used.

The initial implementation lays the groundwork for learning organizational and operational lessons. For example, there are plans to test a virtual operator panel, and any potential obstacles to the plant’s everyday operation will be detected. Challenges that arose in the initial implementation were overcome thanks to the dedication of the project partners. Based on the successful collaboration to date, they are optimistic about the future of the project.

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