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Industrial Ethernet Book 105

OPC UA TSN: a new solution for industrial communication There is a growing belief in market sectors that OPC UA TSN will continue to reveal itself as a game changer in the field of industrial automation, being the first and only candidate for establishing a holistic communication infrastructure from the sensor to the cloud. THE INDUSTRIAL COMMUNICATION MARKET is dominated by Ethernet-based fieldbus systems. Although they share similar requirements and market segments, their implementations and ecosystems differ considerably. The majority have a corresponding umbrella organization guided and financed by one big market player who drives development of the technology. Stakeholders in the value chain are usually not well-aligned in their decisions for particular technologies. As a result, end customers and device manufacturers are faced with a multitude of technologies that need to be produced, run, diagnosed, maintained and kept in stock. While the availability of products and services is largely satisfactory, dealing with multiple solutions generates high costs and limits IoT capability. This joint position paper introduces OPC UA TSN as a vendor-independent successor technology and presents the current view. By choosing the right features, we're able to fulfill today’s and tomorrow’s industrial communication requirements while in the mid-term leveraging the cost benefits of standard Ethernet hardware. The TSN network infrastructure as an evolution of AVB is simultaneously able to carry all types of industrial traffic, from hard real-time to best-effort, while maintaining the individual properties of each method. OPC UA is a major evolution from the OPC communication standards targeting embedded usage. The latest evolution described as Publish/ Subscribe goes further and is aimed at embedded devices, optimizing performance in small footprints. It adds a meta model for describing data, as well as an infrastructure for exchanging and browsing information. Additionally, OPC UA comes with a built-in security model that helps implement secure systems in accordance with upcoming standards like IEC 62443. We anticipate that OPC UA TSN will quickly reveal itself as a game changer in the field of industrial automation, being the first and only candidate for establishing a holistic communication infrastructure from the sensor to the cloud. Industrial communication Industrial communication today is mainly organized according to the automation pyramid. On top, at the computer level, Comparison of minimum cycle times @100Mbit Figure A Light green: Modbus/TCP: yellow-green: SERCOS III: red: POWERLINK; aqua: OPC UA TSN Comparison of minimum cycle times @1Gbit Figure C purple: Modbus/TCP; dark blue: SERCOS III; light blue: POWERLINK magenta: OPC UA TSN standard IT protocols (Internet Protocol Suite) are used. For machine-to-machine and process communication (the distributed controller level), the role of OPC UA (IEC 62541) is rapidly increasing in significance alongside the traditional Ethernet-based M2M fieldbus systems (PROFINET, EtherNet/IP, CC-Link IE). Inside the machine (device and sensor levels), protocols with hard real-time capabilities dominate the field. According to market share, the most significant ones are EtherCAT, PROFINET IRT, POWERLINK and Sercos III. Although these technologies share common requirements, their implementations differ substantially. Comparing them is complicated and depends heavily on the application (process control, motion, I/O, centralized vs. decentralized control, etc.). An endeavor to compare the performance of various real-time Ethernet protocols in a number of categories has been undertaken Figure B Light green: Modbus/TCP: yellow-green: SERCOS III: red: POWERLINK; aqua: OPC UA TSN Figure D grey blue: Profinet IRT*) pink: EtherNet/IP; mid blue: EtherCAT†); magenta: OPC UA TSN by the Ethernet POWERLINK Standardization Group (EPSG). Minimum cycle times Figures A & B @100Mbit, Figures C & D @1Gbit, along with Figure E shows OPC UA TSN @1GBit compared to today’s technologies with 100Mbit, all up to 100 devices and up to a 100 byte payload. The following parameters have been used: • Line topology, output data = 40% of input data, cross traffic for 20% of devices • Forwarding latency @100Mbit: TSN: 3μs, switch: 10 μs, PLK: 0.76 μs, EC: 1.35 μs, SER: 0.63 μs • Forwarding latency @1Gbit: TSN: 780 ns, Switch: 2 μs, PLK: 0.76 μs, EC: 0.85 μs, SER: 0.63 μs • 25% of devices are modular I/Os comprised of 20 slices (affects EtherCAT) Technology 22 industrial ethernet book 4.2018


Industrial Ethernet Book 105
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