New-TechEurope Magazine | November 2017 | Digital Edition

TSN: Converged Network for Industrial IoT

Michael Zapke & Adam Taylor

One of the major challenges to the implementation of the Industrial Internet of Things (IIoT) is the convergence of Information Technology (IT) and Operational Technology (OT) networks. Currently, these networks exist in separate domains. Limited communication in each direction is possible via dedicated gateways. Converging these networks is a key enabler for Cyber Physical Systems in which nodes interact with each other using the Industrial IoT. The current architecture for controlling Factory Automation is hierarchical. Enterprise Resource Planning (ERP) applications at the highest level provide an integrated management and automation of business core processes, progressing down to Manufacturing Execution Systems (MES) that

control the manufacturing process. Programmable Logic Controller (PLC) systems execute the automation tasks using connected industrial devices like electric drives, sensors or I/Os which reside at the lowest level of the hierarchy. This is often called the “Automation Pyramid” (Figure 1), illustrating the broad amount of devices at the bottom and high performance computers at the top. Layers of the pyramid illustrate the hierarchies. Different layers in the Pyramid have different network requirements. While higher layers need high bandwidth and flexible network topologies, lower layers need deterministic behavior and the capability to transport samples in constant intervals with low packet delay variation. This leads to multiple networks that work side-by-side.

A converged network will address several challenges that currently exist in today’s disparate network architecture: More transparency: All data from all hierarchies can be made accessible to every element in the factory without translation in between. Less network planning: More flexible topologies enable easier changes. Less CapEx: Reduction of cabling, reduction of gateways between networks with different protocols. Less OpEx: Reduction of network administration effort. More bandwidth: Avoid limitation to one network speed. Optimized for M2M: Ready for interworking between machines with common data model like OPC UA across the entire factory.

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