If machine and plant manufacturers want to develop collaborative systems, it is all about the interaction between previously independently operated, discrete production units. Everything should become much more fluid, so that the previously segmented production is developing in the direction of the process industry. In terms of communication requirements, this results in a new communication level in the automation pyramid, which is used for inter-machine communication and is integrated above the machine or system-internal process level. And just as the communication requirements clearly increase from the field level to the process level, the data volume at this level also increases significantly compared to the fieldbuses and industrial Ethernet solutions used to date at field and process level. In addition, collaborative robotics is giving rise to new requirements, such as situational awareness, which is implemented using infrared, ultrasound and vision systems, for example. The latter in particular can produce enormous data streams and pose immense data analysis requirements.

Virtualization becomes more attractive

At the same time, there is a second trend that is now becoming ever stronger due to Industry 4.0 and IoT requirements: Virtualization. It has already been used in the past, for example to consolidate a PLC and visualization on a single real-time capable hardware platform.

A new layer is currently being added to the automation pyramid: the Fog server level, which performs functions at station and work unit level and provides direct gateways to the Enterprise and Connected World levels.

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With the additional requirements of Industry 4.0 and IoT, however, there is now not just one (HMI), but two or even three reasons to use virtualization as an essential solution component for possibly even several smart real-time controllers, because both the IoT gateway and the Industry 4.0 communication logic can each be easily separated from other applications in such a virtual machine.

OEMs need a new class of computer technology for the significantly higher data rates in inter-machine communication as well as for the consolidation of controllers on virtual machines together with HMI, IIoT and Industry 4.0 connections: embedded fog servers.

To achieve maximum availability, they should have a redundant design. For short communication paths and therefore low latencies, they must also be able to be installed directly in harsh production environments. Ideally, they should therefore be operated exclusively without fans and be designed for the industrial temperature range. Traditional rack systems are not suitable for this. Embedded fog servers must be designed to be much more compact - just like PLCs, top-hat rail or box PCs. This is why this class of embedded systems is currently emerging. Technologically, platform standards such as the COM Express Type 7 form factor of the PICMG standardization committee provide a good basis for this. It was designed to offer embedded servers performance, to support up to four 10 GbE connections natively for the first time and to enable additional high-speed interfaces for storage and communication via a large number of PCIe lanes - and thus also to be able to connect fast industrial fieldbuses such as Profinet or Ethercat.

Real-time capability is crucial

However, both the server platform with its data processing capacities and the communication channels via 1 GbE or 10 GbE must also be real-time capable. The platform must not lose this capability even during virtualization. Congatec is presenting such a solution at Embedded World.

It will show how real-time systems can exchange real-time data via GbE networks in parallel with intensive data traffic without impairing real-time transmission. The built-in boards support Time Sensitive Networking (TSN), which is also required for communication protocols such as DDS or OPC UA. In a demo, the IEEE 1588 Precision Time Protocol synchronization can be switched on or off via a digital switch to demonstrate the difference in communication behaviour. The Time Protocol enables high-precision synchronization of distributed devices via Ethernet with a fog server. The maximum jitter for standard Intel NICs is in the high-precision nanosecond range.

In order to comply with IEEE 1588, the feature set of the COM Express 10GBASE-KR interfaces includes a software-definable pin for each of the up to four 10 GBE interfaces. This physical pin can be configured as an input or output and is controlled by the corresponding Ethernet controller, which enables the implementation of a hardware-based timing protocol in accordance with IEEE 1588 for high-performance real-time applications.

Multicore platform for real-time virtualization

At Embedded World, congatec will present a demo with time-synchronized GbE Ethernet implementation. In the future, this can replace Ethernet-based protocols that require proprietary controller configurations.

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The platform is based on server-on-modules called Conga-B7AC. The COM Express Type 7 modules with real-time hypervisor from Real-Time Systems are based on Intel Atom processors (code-named Denverton) with up to 16 cores. With these modules, users can provide flexible, real-time-capable edge services at carrier level as well as Industry 4.0 and M2M/IoT services of all kinds.

In addition, dedicated infrastructure components such as firewalls, load balancers and routing systems can be standardized using software-based solutions and consolidated on Fog servers themselves. All this helps OEMs to increase the agility and cost efficiency of their communication infrastructure.

With power consumption starting at just 11 W, the new real-time capable server-on-modules offer up to four times 10 GbE network performance. The feature set is designed for modular micro-servers for industrial use as well as rugged telecom and network equipment - such as small cells, factory gateways and storage systems - and even enables use in the extended temperature range of -40 °C to +85 °C. The conga-B7AC is based on the new COM Express 3.0 specification from PICMG, is available as a standardized building block and is suitable for the efficient customer-specific development of very compact, exclusively passively cooled embedded edge devices.

Potential system configurations

The COM Express module Conga-B7AC offers up to four times 10 GbE.

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In general, there are many different ways to implement a system design, which is one of the advantages of server-on-modules. For example, you can take two Conga B7AC modules and plug them each onto a COM Express Type 7 carrier board from the American manufacturer Connect Tech, which has the same dimensions as the COM Express module itself - i.e. 125 mm × 95 mm. If you then integrate hard disks in between and place the heat sinks of the modules on the outside, the result is a sandwich design that is barely larger than 125 mm × 125 mm × 95 mm (H×W×D) and therefore even fits into control cabinets. It is therefore only a matter of time before OEMs launch the first top-hat rail fog server on the market. The appropriate embedded computer technology is already available.

However, industrial OEM customers will not always find a solution with standard products. They often need very specific carrier board designs, for example to connect fieldbuses or industrial Ethernet protocols that cannot be addressed with standard controllers. The combination of standardized server-on-modules and carrier boards is ideal for precisely such adaptations, as developers can save at least 50 and up to 90 % development time and effort compared to a full custom design.
Computer-on-Modules offer a standardized feature set that is processor-independent and can therefore be reused for several processor families and sockets. It is supplied with complete board support packages that include all module interfaces. There is also detailed documentation on how to design the individual carrier board for the Computer-on-Modules. For this purpose, the standardized COM Express ecosystem provides evaluation carrier boards, from which you can also obtain the layouts to use as a template for your own solutions. Best-practice designs can thus be copied and pasted for your own designs.

Author: Christian Eder is Marketing Director at Congatec.