Today, there are already more networked devices than there are people, and the trend is accelerating. The traditional automation pyramid is being replaced by networked structures and cloud technologies. The requirements on the security, openness, and interoperability of these systems are increasing. Additionally, innovation cycles are being drastically shortened and different development tools and processes are needed to meet the increasingly demanding “time to market”.
These developments have to be taken into account. Today, one year after introducing the PLCnext Technology, Phoenix Contact presents the first industrial controller that is based on PLCnext Technology: PLCnext Control (order designation AXC F 2152).
What makes this controller so special that it can be considered to be the start of a new era in automation?
The PLCnext Control product family starts with a dual-core hardware architecture with 512 MB memory and a system clock rate of 800 MHz. In comparison to conventional PLC technology, this is impressive – but that is not the core innovation. The current device from the PLCnext Control family has been tailored to the market for decentralized, modular small-scale controllers. The first controllers of the high-end series will follow in 2018.
The device from the PLCnext Control family is based on an embedded Linux architecture, with a core that has been expanded to include real-time capability. Linux operating systems have established themselves all over the world and offer advantages such as system integrity, stability, and secure communication, paired with optimal openness and flexibility. These benefits can now be utilized in industrial automation as well. Linux also offers the best portability to various hardware platforms and makes scaling or the use of future processor architecture possible.
The open platform for different programming languages
Even in the early development phase, the advantages of an open platform became apparent. Experts of the Phoenix Contact Group were able to make necessary modifications to the realtime section of the operating system core by themselves. A decisive step which would have been unthinkable in a proprietary world. Here the many years of experience that Phoenix Contact Cyber Security AG has with Linux-based operating systems also helped. The security devices of the subsidiary are also Linux-based and regularly require special measures during the so-called “hardening” of the system architecture, which is of particular relevance in control technology as well.
The core of the PLCnext Technology uses this robust operating system positioned one level higher in the system architecture. It is important to optimally condition the strengths of the hardware and operating system for the user and to simultaneously make the applications performant, robust, communicative and, above all, secure.
Until recently, controller programming – assuming it is deterministic in principle – was only possible using defined PLC programming languages. Here PLCnext technology significantly simplifies the engineering: It represents an open platform on which multiple developers, from different generations and programming disciplines or domains, can work in parallel on one control program. While PLC programmers are programming the sequential control system of a system or machine in IEC 61131, individual system components, such as elements with optical pattern recognition or signal analysis, can be programmed in a high-level language in parallel. This happens in the respective programming environment and with the programming tools of the respective domain.
Unlike previously, the various program sequences must not be integrated into an IEC 61131 task for them to run in a deterministic fashion. The Taskhandling Execution Synchronization Manager (ESM) of PLCnext Technology, on which the patent is pending, makes it possible to combine programs from a range of development environments with one another or within tasks, yet have them behave like homogeneous IEC 61131 code. This automatically makes high-level languages deterministic as well. Task handling therefore supports a mix of IEC 61131, high-level, and model-based languages.
ESM ensures that programs in different tasks run with the required temporal determinism and that these tasks are also synchronized with each other. What’s new is that these tasks can be receiving input from various programming domains. The individual tasks can even consist of programming elements that originate from different programming domains. This provides almost unlimited creative freedom for new programming approaches and new applications.
Software and expertise from the open source community can also be used. In addition, services and apps from the cloud can be easily integrated in order to expand the control functionality. The second technological aspect is the consistency of the data of the process image. In PLCnext, this is handled by the “Global Data Space“ (GDS),” for which a patent has also been filed.
Using sophisticated mechanisms with internal port and data buffer structures, the GDS ensures that the individual program elements receive the precise and consistent data image that is crucial for running the respective program successfully. The significance of data consistency becomes clear if one images a scenario with four tasks that might be distributed among different processor cores, with the tasks in turn consisting of programming elements from different programming domains, with different priorities, task cycle times and interdependencies between the tasks. Regardless of the priority of a task and the code blocks used in the task, a consistent process image is present during the entire task cycle. This safeguards that a task works unvaryingly and in ways that make sense, even if a measurement value changes during the task processing. Each task thus has a consistent process image, so that secure and meaningful task results are obtained. This applies not only to the realtime section of the controller, but also to the usable non-realtime section, in which Java elements can be carried out for example.
In addition to the ESM and GDS core elements of the PLCnext Technology, the controller has all features of a modern controller. This means an OPC UA server has been implemented, as well as system, user, and fieldbus managers, diagnostic loggers, trace controllers, PC Worx Engineer HMI, and automatic access to Proficloud, which is free of charge for the first year.
In 2018, the first system extensions will follow, such as integration of the safety technology.
Early adopters successfully make use of the open concept
Within the framework of a new early adopter program, which was launched at the Hannover Messe 2017, the first Phoenix Contact customers were able to get experience with PLCnext Technology. More than 100 customers from twenty countries participated in the program and simultaneously used new support and cooperation approaches via communities set up especially for this purpose. The reactions show that the users profitably implement the advantages of the new system approach. Within a short period, the first applications that use the system’s openness were created, for example by using the latest language recognition modules from the Home area in machine control systems. Furthermore, data analysis tools in the non-realtime section were linked with realtime data from machine control systems, for data analytics or predictive maintenance approaches. These usages show that, even today, PLCnext Technology is able to meet new demands in industrial automation. As the requirements grow, the system will grow too – through app and open source approaches or through the collaboration in communities. The users also considered the domain-independent programming to be a substantial benefit. If one takes a look at graduates of technical education programs, a shift in their skills is noticeable. Twenty years ago, the graduates had know-how in the field of programmable logic controllers. Today, they are competent in high-level-language programming, modeling system tools such as Matlab, Simulink or also Java. The PLCnext Technology becomes the binding element between the different programmer generations that have to be able to use their acquired skills within the same automation project.
PLCnext Technology provides the basis for cutting-edge automation solutions capable of meeting all the challenges of the digitized world.
– Excerpted from the speech of Roland Bent, Chief Technology Officer of Phoenix Contact GmbH & Co. KG, given at the SPS IPC Drives 2017 fair in Nuremberg, Germany