In a recent InnoTalk webcast, an Advantech expert panel considered an emerging technology with potentially transformative effect on the automation industries and on the convergence of OT and IT systems. It is Time Sensitive Networking, or TSN. They discuss the problems TSN ethernet solves, how it does it, and what impact it will have on existing automation installations.
Where does TSN fit in the automation hierarchy?
Today we have very different real-time ethernet solutions in use across the industry. Yet, although most are part of international standards, they are all incompatible with each other. This means that when users want to achieve a certain performance, they need specific hardware, not the standard ethernet controllers. Moreover, most industrial ethernet networks cannot coexist in a common infrastructure. This has led to the situation where we have different ecosystems built around some of the major automation suppliers.
This introduces extreme complexity and significant costs for users and the suppliers that deliver and need to support these different ecosystems. TSN is a different ethernet approach because it can harmonise this situation.
How does TSN ethernet solve problems?
TSN is a common communications infrastructure for an entire system and covers time-sensitive, time-insensitive, and soft real-time monitoring needs. Importantly, it can also provide for the hard real-time elements in the production process. It paves the way for greater digitalisation across an entire business, which in turn is going to produce economic benefits.
Ethernet is a standard and works well. Because it’s a standard, everything is cheaper because there are many competitors in the marketplace. But the problem for many automation applications is that it is not deterministic. This means with ethernet, users cannot guarantee the delivery of data from point A to point B within a certain time frame.
How does TSN address this?
The development of TSN ethernet allows standard ethernet to become deterministic based on the IEEE standards. Essentially, with TSN it works by time slicing/synchronising the ethernet data flow into streams. TSN rules for handling the streams allows it to ensure time synchronisation over standard ethernet.
It can also deliver latency on a high-priority stream of between one to two milliseconds on the actual ethernet data stream. This meets the challenges from applications like motion, safety, and synchronisation between machines on the factory floor. With a high-priority stream, it offers 125 microseconds for each time segment that can come through.
How does TSN ethernet fit into existing automation installations?
TSN is not a disruptive technology, so users do not need to throw away all their investments. The migration is straightforward because TSN is ethernet, so the physical layer, layer one, that installers and users are familiar with is the same. But users can make a step-by-step migration towards TSN. They can put in place a TSN infrastructure and then have a template enabling them to classify and control the traffic they want over the TSN network.
But it’s a step-by-step procedure. This means users can keep installations with machines that are using the existing technologies with the different real-time ethernet standards. For example, you can use TSN within a machine even if the endpoints are not TSN-aware.
In the first step, machines could connect with a TSN network, using OPC UA to drive more horizontal connectivity and horizontal communication, including scaling up to the edge. The next step is to move TSN into the machines themselves or into their specific installations. This step brings harmonisation into the machines through vertical communication and finally achieves a consistent solution that is scaling vertically and horizontally. A future-proof technology in the making.
The key thing behind TSN ethernet is gradual implementation. It is not a big bang where everything must go. Users can move forward on the implementation at a pace that suits them. It is a continuous upgrade capability.
Go here for the Advantech InnoTalk webcast.
