The trend in automation is clear: more axes, more sensors, more connectivity - and ultimately more data. In other words: Industry 4.0 relies on more information, the greater flexibility of machines comes at the price of more complex arrangements of drives, robot arms and the increased use of image and video technology. The collection and processing of this mass of data in smart production requires more resources, including new technologies such as machine learning or artificial intelligence. The computing capacities and memory capacity of conventional control systems can barely keep pace with this development. Some applications also require a Windows environment.

Such a scenario is not a problem for IT: the cloud provides virtually infinite resources for data storage and processing, including virtual environments with different operating systems if required. But different rules apply on the store floor. Limited network capacities and cost aspects set limits to the use of the cloud in critical areas of automation.

The performance of control systems increases with each new CPU generation, the sometimes limited data memory can be significantly expanded with the help of expansion cards and the read and write speed of these memory cards has also improved. However, as long as control processors remain limited to the ARM and Atom class, even more modern PLCs offer only limited potential for increasing performance.

In contrast, the use of PC technology, which also enables the use of Windows-based applications, promises greater performance. Certain tasks can be outsourced to these for faster processing, and only the results are fed back into the PLC controller. However, this technology requires more engineering effort, takes up more space in the control cabinet and requires additional cabling.

Against this background, Lenze has been thinking about a future-proof control architecture and has finally laid the foundation for a new generation of controllers with the c550 Cabinet Controller, in order to be able to solve even extremely power-hungry automation tasks. The basis for this is the Intel Core i7-7600U processor with two cores and 2.8 GHz clock speed (see box). This CPU redefines the upper performance limit for controllers.

The controller thus competes with solutions for which only industrial PCs were previously considered due to the pure performance requirements. Instead, the machine manufacturer can now fall back on the smaller form factor of the PLC and also use the standard software modules of the FAST toolbox from Lenze, including the modules created for this purpose as well as self-developed modules. Existing programs or program modules in accordance with IEC 61131-3 and projects based on the Codesys programming environment can also continue to be used.

One is better than two

By using the latest processor technology and an intelligent housing design, the new generation of controllers pushes the boundaries of what is technically feasible for this form factor.

© Lenez

The c750 model, which is based on the same hardware, further blurs the distinction between PLC and industrial PC. This is because this controller covers applications in which Windows applications are absolutely essential. The OpenSystem architecture used here divides the computing power between two independent operating systems: The real-time Linux is responsible for control tasks, while the open Windows 10 IoT Enterprise is available for user-specific software applications.

Each of these systems runs on a physical processor core that splits into two virtual cores and can therefore process two tasks in parallel. This is made possible by the virtualization integrated in the CPU at processor level, which allows direct allocation of the available resources (processor cores/memory/interfaces). In the Cabinet Controller c750, the display port, a Gigabit LAN connection, the USB 3.0 port and the CFast SSD slot are assigned to the Windows system. Ethercat master, a second Gigabit LAN and the USB 2.0 port are linked to the PLC part.

The most common Windows applications include database applications such as recipe management and data analysis, sometimes with the help of machine learning, for example for predictive maintenance. Image recognition for barcode readers and 2D/3D scanners or vision applications are also usually dependent on Windows, as are teaching applications for the simple training of robots.

Data exchange with the cloud is becoming increasingly relevant. Data pre-processing, for example in the form of average values over a measurement interval, the reduction of measurement points to be transmitted or the filtering out of deviating measurement values can help to significantly reduce the volume of data to be transmitted to the cloud. On the one hand, this reduces network traffic on the store floor and on external communication channels, and on the other, it helps to save costs for the cloud application, as its billing is often based on the volume of data transferred.

At the heart of this combination of PLC and PC in one device is the uncompromising stability of the machine control system. The two operating systems are completely independent of each other: If the Windows 10 IoT Enterprise crashes on the PC part, the controller part continues to run completely undisturbed - but without the calculations that have been outsourced to the PC part. The Cabinet Controller c750 is therefore just as reliable as the combination of a controller and a PC, each with its own hardware.

The same applies to safety: despite the integration in one housing and the shared CPU, the PLC and Windows sections each have their own network. Although they can communicate with each other internally, they can also be sealed off from each other with the usual security measures so that malware or attacks on the Windows PC do not automatically endanger the PLC.

There are also interesting economic advantages. This is because certain assemblies do not have to be duplicated. Cabling is simpler, and less effort is required for the OEM when programming and maintaining the system, as the developer only has to connect to one system instead of working on two devices in parallel. The dimensions of the control cabinet benefit from the compact form factor. There is usually little space here, and it is often not possible to change the external dimensions in the substructure of machines or drives in order to accommodate an additional PC.

Last but not least, the integration of PLC and PC makes many things easier for the system operator: joint device monitoring, simpler status transfer and integrated power-down handling are just a few examples.

IT meets OT

With X4 Remote, Lenze has developed its own service portal. The IoTGateway x500 supports Ethernet or Wi-Fi Internet connections.

© Lenze

With the widespread use of OPC UA as a standard in many automation solutions and components, end-to-end networking from field level to the cloud has become possible on a broad front. As already mentioned, the Cabinet Controller c750 can pre-process the data collected in this way in a cloud-compatible manner. Lenze has developed the 'X4 Remote' solution for the final step, the integration of the machines in a smart factory not only into overlaying systems such as SCADA, MES and ERP, but also into the cloud. This consists of cloud gateways and a cloud-based range of web services. Both Lenze controllers and PLCs from other manufacturers can be connected.

With this solution, the collected machine data is logged and stored in data clusters. Evaluations can be visualized in self-configured dashboards and can optionally also be called up on mobile devices. The cloud solution can be used to set up live monitoring and alarms and create additional services, such as remote maintenance and machine diagnostics. Modern interfaces open the way to other services, such as business intelligence applications. Advanced encryption technology and sophisticated user and device management, which includes unique authentication and authorization, ensure the security of data in the cloud.

Powerful heart for control technology

In the c550 and c750 cabinet controllers, Lenze is installing the most powerful Intel CPU currently available for industrial use in highly compact designs. The processor with the designation Intel Core i7-7600U 2.8 GHz (7th generation, Kaby Lake architecture) has several advantages compared to commonly used ARM and Atom CPUs, including

• Higher processor and memory clock rate
• Two physical or four logical processor cores that can perform tasks independently of each other
• More modern interfaces, thus accelerated connectivity and larger memory spaces can be addressed.
• Support for numerous graphics formats at processor level, making it easier and an order of magnitude faster to process image and video formats.
• Integrated virtualization, without which the operation of two parallel operating systems would not be possible, and supporting security technologies including commands for fast data encryption.

All in all, the Intel i7 CPU is significantly more powerful. With the help of new processor instructions that perform tasks 'in silicon' - i.e. in specialized areas of the CPU - faster and with less energy consumption than if they were simply processed in software, it is nevertheless more effective. However, compared to an Intel Atom processor with four cores, which is strong in its class, it also occupies 35% more space.

Author:
Martin Kluge is Head of Product Management Automation Systems at Lenze.