New Class of Embedded Design Emerges to Support Virtualized Fog Servers

Real time has taken on a new dimension with the advent of Industry 4.0. It is no longer enough for controls to communicate with sensors and actuators. Today, real-time communication is also required between industrial plants and machines as well as their incoming and outgoing systems, a demand being met by real-time-capable virtualized fog servers with redundant design for high availability.

The key challenge for machinery and plant manufacturers wanting to develop collaborative systems is fostering interoperability among discrete production units that previously operated independently. Everything needs to become a lot more fluid to allow previously segmented production to evolve towards the process industry. This requires a new communication level in the automation pyramid (Figure 1) that handles machine-to-machine (M2M) communication and sits above the internal process level of the machine or plant. Communication requirements increase when transitioning from field to process level. So too do data volumes, which are significantly higher at this new level compared to data volumes with field- and process-level common fieldbuses and industrial Ethernet solutions. In addition, collaborative robotics creates entirely new requirements such as situational awareness, which is implemented, for example, via infrared, ultrasound, and vision systems. The latter in particular can generate gigantic data streams requiring immense data analysis.

Figure 1: A new layer is currently being added to the automation pyramid: the fog server (or Industry 4.0) level which lies between the enterprise and process levels. In accordance with the IEC 62264 / IEC615112 hierarchy level[1], it fulfills station and work unit level functions while also providing direct gateways to the enterprise and connected world level.

Gaining Traction: Consolidation via Virtualization
While virtualization is already being used, for instance, to consolidate a PLC and machine vision on a single real-time hardware platform, Industry 4.0 and IoT demands are now supplying not just one reason—control plus HMI—but two or three reasons—control(s) plus HMI plus IoT plus M2M —to utilize virtualization as pivotal to smart real-time controller solutions (Figure 2).

Figure 2: Assigning virtual machines to individual cores and operating them in privileged mode enables even hard real-time systems to work with Windows GUI servers and Linux web servers.

To manage the significantly higher data rates in M2M communications as well as the consolidation of virtual machine controllers along with HMI, IIoT, and Industry 4.0 connectivity, OEMs need a new class of embedded computer technology: embedded fog servers. They should be designed redundantly to achieve highest availability. To allow short communication paths and low latencies, they must also be optimized for direct installation in harsh production environments. Ideally, they should therefore be designed for fully fanless operation and industrial temperature ranges. Standard rack systems are not suitable in this case. Embedded fog servers need a much more compact design, such as PLCs, DIN rail, or box PCs. This is why a new class of embedded systems is currently being developed. Platform standards such as the COM Express Type 7 form factor by the PICMG standardization body provide a sound technological basis for this. Designed to provide embedded server performance, this form factor natively supports up to four 10 GbE connections for the first time and provides additional high-speed storage and communication interfaces across a variety of PCIe lanes for the connection of fast industrial fieldbuses such as PROFINET or EtherCAT.

Real-Time Capability is Crucial
However, it is important that both the embedded edge server platform with its data processing capabilities and the 1/10GbE communication channels are real-time capable. The platform must never lose this capability, even with virtualization. congatec is presenting such a solution at Embedded World (Figure 3). It demonstrates how real-time systems can exchange real-time data via a GbE network in parallel with intensive data traffic without impacting real-time transmission. For this purpose, the boards support time-sensitive networking (TSN), which is also required for communication protocols such as DDS or OPC UA. In the demo, the IEEE 1588 Precision Time Protocol synchronization can be switched on or off via a digital switch in order to demonstrate the difference in communication behavior. The IEEE 1588 Precision Time Protocol enables high-precision synchronization of distributed devices with a fog server via Ethernet. The maximum jitter in standard Intel® NICs lies in the high-precision nanosecond range.

To comply with IEEE 1588, the feature set of the COM Express 10GBASE-KR interfaces provides a software definable pin for each of the up to four 10GbE interfaces. This physical pin can be configured as an input or output and is controlled by the associated Ethernet controller. This enables the implementation of an IEEE 1588 compliant hardware-based timing protocol for powerful real-time applications.

Figure 3: At Embedded World, congatec will be demonstrating a time-synchronized GbE implementation that also acts as a substitute for Ethernet-based protocols requiring proprietary controllers

Low-Power Multicore Platform for Real-time Virtualization
The platform utilizes Intel® Atom™ processor (codename Denverton) based COM Express Type 7 modules with the real-time hypervisor from Real-Time Systems. Customers benefit from application-ready, virtualized, fanless embedded server platforms with up to 16 cores, enabling them to deliver highly flexible, real-time carrier-grade edge, Industry 4.0 and M2M/IoT services of all types. 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. All of this helps OEMs to increase the agility and cost-effectiveness of their communications infrastructure.

With power consumption starting from 11 watts, the new, real-time low-power Server-on Modules provide up to 4x 10GbE of network performance with up to 16 cores. The feature set is designed for modular industrial micro servers as well as rugged telecom and network equipment—such as small cells, factory gateways and storage systems—and even allows use in the extended temperature range of -40 °C to +85 °C. One solution based on PICMG’s new COM Express 3.0 specification is the congatec conga-B7AC module. This Server-on-Module is available as a standardized building block and perfectly suited for efficient custom development of very compact, passively cooled embedded edge devices.

System Configuration Options
There are generally many different ways to implement a system design, which is one of the advantages of Server-on-Modules. For example, you can mount two conga-B7AC modules on a COM Express Type 7 carrier board from Connect Tech, which has the same dimensions as the COM Express module itself, i.e. 125 x 95 mm. If you sandwich hard disks in between the modules and place the heat sinks on the outside, the complete design is barely larger than 125 x 125 x 95 mm (H x W x D) and even fits in control cabinets (Figure 4). It is therefore only a matter of time before OEMs bring the first DIN rail fog server to market; the right embedded computer technology is already available off the shelf.

Figure 4: With COM Express, redundant industrial edge servers for up to 16 virtual machines can fit comfortably inside a control cabinet.

Custom Carrier Boards
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 such adaptations, allowing developers to save at least 50% and up to 90% in development time and NRE costs compared to a full-custom design. For this purpose, Server-on-Modules offer a standardized, processor-independent feature set that can be reused for multiple processor families and sockets. They ship with complete Board Support Packages (BSPs) covering all module interfaces, and there is extensive documentation on how to design the individual carrier board. In addition, the standardized COM Express ecosystem provides evaluation carrier boards, for which the layouts can also be obtained and used as templates for your own solutions, with best practice designs utilized via copy and paste.

Dan Demers is the Director of Sales & Marketing – Americas at congatec, Inc. He holds a B.B.S degree in International Business from Grand Valley State University, Grand Rapids, Michigan and an M.B.A. from Ashford University, Clinton, Iowa. Mr. Demers has over 19 years of experience in embedded computing having worked with Fortune 500 companies in the Industrial, Medical, and Communications markets.


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