TSN Update
OPC UA over TSN – experiences with integration and evaluation IN SEPTEMBER 2016, A GROUP OF THE WORLD’S largest automation companies announced an initiative at SPS for the standardization of OPC UA over TSN as a universal, vendorindependent industrial communication platform. From the onset the goals of full interoperability and convergence for industrial automation components and data access “from sensor to cloud” were clear. However, large parts of the technology were new and not yet proven in industrial use, industrial standards needed to be created to achieve openness and interoperability, and major obstacles to technical realization were expected by some skeptical voices. In this article, we will look at the situation today and see how users of the technology who are currently integrating and evaluating OPC UA over TSN for their automation components and systems fared with respect to these concerns.
Users of OPC UA over TSN
As a supplier of the core technology elements, TTTech Industrial is working with automation component manufacturers that are integrating TSN capabilities into their products. We are also discussing benefits, developing prototypes, and evaluating functionality and performance of OPC UA over TSN with potential end users who want to prepare for the introduction of the technology into their systems and get a better understanding of the implications, capabilities and possible pitfalls. This has given us insight not only into requirements and upcoming use cases for this technology, but also into the practical issues that potential users of this technology have encountered, and will encounter, when getting hands-on with OPC UA over TSN products. Depending on the position of their product in the automation system hierarchy, companies need very different building blocks and steps for integrating and utilizing these technologies. Chip makers adding TSN capabilities to their switch chips or NIC components can integrate TSN features into their FPGAs and ASICs for use in standalone switches or switched endpoints. There are also some TSN-enabled endpoint chips such as the Intel i225. Device manufacturers developing TSN enabled industrial switches and endpoints 04.202 1
SOURCE: SHUTTERSTOCK
The need for edge computing means more connected devices that interact with the real-world based on the data they receive. As computing power becomes pervasive, so does the need for security to address increased cyber risk. Only relying on firewalls is no longer effective with converged IT and OT networks.
OPC UA over TSN has already proven itself ready for several industrial use cases. using either dedicated ASICs or an FPGA-based solution for TSN networking, as well as software stacks implementing various Ethernet and TSN related protocols and functions such as synchronization and configuration. For OPC UA, embedded stacks are available from several vendors and open source initiatives. System integrators building entire systems such as machines or production cells can most clearly see the benefits of OPC UA over TSN, as they are particularly evident on the system level. The controllers and devices used to build the system must include the hardware and software components to enable the use of OPC UA over TSN on the system level, and the system integrator needs configuration and testing capabilities for OPC UA over TSN. In this article, we are contrasting the expectations and doubts that accompanied the initial steps to develop OPC UA over TSN as an industry-wide standard for communication with the experiences and feedback regarding OPC UA over TSN prototypes for machine-tomachine use cases. These experiences result from concrete evaluations and integration of solutions by technical specialists together with customers during the past year. This provides a ‘snapshot’ which shows which steps are typically taken to evaluate current state-of-the-art building blocks for this technology, how relevant some of the initial concerns were and if they have been
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resolved, which expectations were met, and where more development is needed. It also shows how different use cases can drive and adopt the same technology with very different focus and speed. When we discuss various issues that early adopters encountered with this technology, we will try to separate what is inherent in the technology e.g. resource consumption of software stacks, from what is related to product design e.g. user interfaces of configuration tools. Feedback from early customers allows vendors to improve their products with respect to functionality, performance, and usability, while constraints and issues relating to the technology itself should not be resolved by vendors in a proprietary way and instead need to be addressed by industry standards. The ongoing TSN work on configuration enhancements (IEEE 802.1Qdj) is an example for this.
Evaluating TSN separately from OPC UA To fully experience the benefits of vendorindependent interoperability and IoT connectivity from sensor to cloud requires that OPC UA and TSN are used in combination, but this is not a hard technical requirement and the two technologies offer independent functionality. Many companies interested in the combination of OPC UA and TSN have prior
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