As the need for quicker development cycles while minimizing risks continuously grows, many companies rely on digital twins to accelerate industrial automation applications. Gartner predicts that by 2021 50% of large industrial companies will use digital twins to drive new business models and further evolve industrial automation processes. The market volume of digital twins was at $3.8 billion in 2019 and is estimated to grow to $35.8 billion by 2025.
The need for more flexible, cost-effective, and reliable plants has also given rise to model-based testing of these plants. To use these models extensively and thoroughly to validate industrial equipment through all development stages, digital twins are indispensable from design to pre-commissioning. Digital twins are a digital copy of a physical system, for example, a factory floor. To test new control algorithms, engineers can use the digital twin instead of shutting down the factory floor to test the physical system's algorithms. With this use of a digital twin, a company can move faster from testing and validating to implementing new control algorithms all-the-while not losing money since there are no production stops. In continuously testing and verifying the algorithms, engineers can increase the simulation model's quality and functionality.
Furthermore, they can detect coding errors at a very early stage of the development process. To operate these systems, programmable logic controllers (PLCs) are indispensable. But why are PLCs driving growth, and why are they crucial for applications such as predictive maintenance, virtual commissioning, and other industry 4.0 topics such as smart factory and factory acceptance tests?
First Reason: PLC Testing Is Key
PLCs are industrial digital computers that control manufacturing processes. They range from small modular devices to large modular devices. Furthermore, they are often connected to other PLCs and Supervisory control and data acquisition (SCADA) systems. Application areas for PLCs are assembly lines, robotic devices (e.g., cobots), or any activity requiring high reliability, ease of programming, and process fault diagnosis.
In short: to have all processes executed as desired, the PLC must react accordingly to the input given within a short period of time. Why exactly PLCs are at the heart of industrial automation can also be explained through history, which brings me to the next point.
Second Reason: PLCs Have Been Here to Stay for a Long Time
First introduced in the late1960s PLCs by the automobile manufacturing industry, PLCs have revolutionized the automation industry. By moving away from using relays, the idea was to find a way to control manufacturing processes with computers' help. The novelty of the PLC was that the inventor Dick Morley found a way to represent computer scientists' thinking so that plan engineers could warm to this invention.
The first PLC, the Modicon 084, was not yet a box-office hit, but that changed with the Modicon 184. From then on, demand grew steadily, which also fuelled competition between the newly founded PLC manufacturers, leading to innovations and smaller devices (the first PLC from Modicon, the Modicon 084, was as big as a suitcase) to further facilitate the plant's support and maintenance. Apart from the fact that PLCs have become smaller, speed must be emphasized. The fact that PLCs can process signals increasingly faster has reduced cycle times and increased communication possibilities. PLCs also have ever larger memory capacities. In short: PLCs are becoming better, smaller, and faster.
Depending on the application, innovations and new PLC solutions will become more and more critical. The more they can do, the more important it becomes to apply PLC testing correctly. According to Philipp H. F. Wallner, industry manager for industrial automation and machinery at MathWorks, "a modern PLC can run sophisticated control algorithms, and process advanced data signals in real-time, which would not have been possible 10 years ago. The first multi-core processors on PLCs are already in production use. Also, intelligent sensors have become so affordable that machine builders now integrate them in places it was economically impossible to a few years ago".
Third Reason: PLCs Have More and More Capabilities
The new possibilities in hardware performance have also led to the further development of the PLC. This development is relevant because it offers more individual and leaner process possibilities, designed to meet specific requirements.
Philip Wallner illustrates this very clearly in his article 5 trends changing industry using our smartphones. While the shell, i.e., the smartphone's skeleton, remains the same over the years, the software changes with every update we download. This sheds light on how the industrial automation industry wants to approaches the role of the PLC. It is not a matter of rebuilding the entire physical plant every year (this would not make sense for cost reasons alone) and building a software and control infrastructure that allows individual components to be updated so that the entire system remains up-to-date.
Fourth Reason: PLCs Can Handle Future Complexities
With more capabilities come more complexities. Not only the PLC itself has evolved, but also inventions that are indispensable for the PLC, such as communication protocols. These improvements are possible due to processor development: As processors become faster and faster and memory capacities larger and larger, PLC solutions and possibilities arise that were previously unthinkable. These include vision system integration, motion control, as well as synchronized support for multiple communication protocols.
Fifth Reason: PLCs Are Versatile and Will Forster More Growth in Industrial Machinery
Although PLC testing is becoming increasingly complex, it is indispensable for industrial automation. The many possibilities which result from this will probably open doors for new inventions and groundbreaking innovations in the future.
Therefore, it must be assumed that PLC solutions will continue to evolve in the future to drive innovation in the industry. New challenges, such as implementing machine learning, predictive maintenance, and virtual commissioning algorithms, or creating a digital twin of an entire plant, will continue to drive PLC complexity.
Those who deal with topics in the Industry 4.0 area and deal with them will recognize the importance of the PLC and the importance of model-based design and related workflows (in this context, Hardware-in-the-Loop).
For more information on the history of PLCs and industrial automation trends, check out the following resources:
History of the PLC published in the automationdirect library
PLC Programming Then & Now: The History of PLC’s by c3controllers
5 trends changing industry by Philipp H. F. Wallner
Prepare for the Impact of Digital Twins by Christy Pettey
Using a Supply Chain Digital Twin to Improve Logistics by Scott Shaw
I hope you've enjoyed this post, and as always: stay curious!