Why OPC UA Over TSN Will Prove Critical to Manufacturing IIoT

Industrial system interoperability is on the way through a combination of the determinism supplied by Time-Sensitive Networking and OPC UA’s machine-to-machine communications to better synchronize machinery on the plant floor and the device-level communication inside those machines, regardless of supplier.

The combination of Time-Sensitive Networking (TSN) and OPC UA will prove vital to manufacturers implementing Industrial Internet of Things (IIoT). And it’s on its way, with OPC UA over TSN automation products entering the marketplace as early as this fall.

The reasons this new standard is so important can be summed up in three words: interoperability, performance, and security.

Time synchronization is critical for industrial automation capabilities such as device-level control, motion control, machine vision, and machine-to-machine control. The various fieldbuses each have their own mechanisms to achieve deterministic behavior on the network. TSN extends the IEEE 802.1 Ethernet standard for real-time communication, providing a single standard meeting industrial automation requirements.

TSN also enables the possibility of converged networks, for deterministic operational technology (OT) communications such as machine control and safety, and non-deterministic information technology (IT) traffic across the same network.

The technology is capable of addressing 10,000 network nodes, scalable from 10 Mb to 10 Gb. B&R conducted a test achieving cycle times below 50 µs with a jitter of ±100 ns in a network of 200 remote I/O modules. This is consistent with claims that OPC UA over TSN is 18 times faster than today’s fastest solution.

But TSN is only half the story. OPC UA provides interoperability and has built-in security. Its companion specifications allow a machine to describe itself in the same way, with standardized semantics. OPC UA is widely supported and new developments continue to be supported; it is also a recognized international standard for communication from sensor to cloud. The new OPC UA publish/subscribe initiative also supports faster communications than client/server.

As automation users, machine builders, and automation device suppliers are painfully aware, today’s fieldbuses, even if they run on Ethernet wires, are not interoperable. For decades, the automation industry has had to support multiple fieldbuses and work around the lack of connectivity between them.

Interoperability is necessary to reach the next level of automation, the exchange of information, the digitalization of manufacturing, and the rise of the smart factory. Just as IIoT requires higher levels of data acquisition, analysis, and optimization, it also requires interoperability across platforms.

Together with TSN’s determinism, OPC UA allows machine-to-machine communications to better synchronize machinery on the plant floor, regardless of supplier. The same holds true for device-level communication inside the machines.

The design of effective production processes, time, and cost reduction in commissioning and maintenance, and the mass customization of products are the aspirations of IIoT. This requires changes to current production lines to become flexible and provide ongoing insight into the production processes to perform process optimization and predictive maintenance without disturbing machine operations.

IIoT is going to call for a converged, interoperable OT/IT network, from sensor to cloud, and OPC UA over TSN is going to enable that. Cloud platforms today support an OPC UA connector, simplifying communication.

OPC UA over TSN is intended to replace the various fieldbus protocols with one standardized, deterministic industrial Ethernet, interoperable across the Open Systems Interconnection (OSI) model.

Most major automation technology providers are supporting the OPC Foundation’s OPC UA over TSN for field-level communication initiative. Twenty-three companies that share the same vision participate in an OPC Foundation steering committee dedicated to extending OPC UA for field-level communication over TSN for seamless communication from sensor to cloud.

"The future of industrial networking just got a lot brighter," the ARC report concludes. "In a significant move, the OPC Foundation announced in late 2018 that it will now actively promote its Publish-Subscribe model for communication with devices at the field level. In addition, time-sensitive networking (TSN), a mechanism for time synchronization and determinism, is quickly gaining acceptance among industry players. The combination of these two technologies is paving the way for the emergence of a single, universal solution for Ethernet in industrial applications that may one day replace today’s industrial Ethernet solutions."

Source : automationworld.com