Time-sensitive networking (TSN) insights

• Ethernet has continued to improve and broaden its reach and has been expanding into industrial automation applications.
• Time-sensitive networking (TSN) delivers functionality for device clock synchronization, traffic prioritization and traffic shaping and can help manufacturers improve communication and scheduling.
• TSN is part of a larger initiative by manufacturers looking to improve their supply chain and maintenance schedules and reduce potential logjams.

Fundamentally, Ethernet is a nondeterministic technology, letting devices on the network take turns in sending messages. Devices listen for a quiet moment at which to transmit a message. If two devices transmit at the same time, they recognize a collision and back off for varying periods to avoid another collision. Ethernet has been applied to applications requiring communication determinism, but it is up to the devices on the network to work in unison toward the outcome, not something that is possible in an “open” network.

In 2018 that changed with the addition of time-sensitive networking (TSN) specification additions. TSN delivers functionality for device clock synchronization, traffic prioritization and traffic shaping. These features enable devices to coordinate their communication schedules, preempt traffic as necessary and break up large transmissions to intersperse higher priority messages. This combination enables Ethernet to be applied to one of the most demanding areas of communication.

Ethernet’s benefits include low-cost cabling, ease of use and flexible architectures. With all devices on one network, the real benefit is data access. Adding TSN delivers a whole new dimension.

TSN’s main benefits are determinism and convergence.

Determinism is fundamental to supporting time-critical communications on the factory floor, as it ensures the predictable delivery of data by minimizing latency and jitter. This requires that the Ethernet specification is enhanced in three areas:

• Delivering an accurate time synchronization to all devices on the network can communicate intelligently and in a coordinated fashion.

• That traffic can be shaped — large transmissions can be broken into many smaller transmissions to enable preemption by higher priority traffic.

• The ability to define prioritization to communications between devices. This supports real-time applications and provides the foundation for convergence.

Convergence, the second key benefit of TSN, enables companies to merge different traffic types onto a single network without affecting the performance of shop floor communications. This is fundamental to sharing operational insights and hence increasing process transparency across an enterprise, which can then be used to derive insights to optimize manufacturing facilities and entire organizations.

Four network convergence benefits

Because TSN is an extension of Ethernet, it also is interoperable with existing network technologies and devices. Hence it can be used alongside existing devices, reducing system investments.

Converged networks provide users with four benefits:

1. Control devices that have previously been isolated to separated control networks – required to ensure deterministic performance, can now be addressable and accessible to other applications for use in advanced analytics and digital twins,

2. Devices are becoming smarter and more complex and require management that can now be accomplished over one connection,

3. Architectures are simplified through the use of one network, improving deployment and troubleshooting and

4. Costs are reduced, through the simplification of architectures.

Three benefits of leveraging TSN

Leveraging TSN enables the development and use of smarter machines and has many benefits for users. Three, in particular, stand out:

1. Provide external access to all machine variables.

In the past, this has been one of the greatest challenges, primarily because communications within a machine fall into various categories and have differing requirements. There is typically a control network and a supervisory network. There can be a bridge to an external network.

Some communications require deterministic performance for processes such as motion control or high reliability for safety. Other communications are less demanding and are for informational purposes. The gateway for these communications often becomes the controller. There should be a common backbone for all machine communications. With new products on the market that support TSN, machine builders can now deliver machines with a common Ethernet TSN backbone, enabling direct data access with the entire machine, from controller to sensors and actuators.

Figure 1: Time-sensitive networking (TSN) allows multiple networks to exist on a single wire. Courtesy: CC-Link Partner Association (CLPA)

2. Instrumenting a machine with additional sensors to enable greater context.

Greater access to machine data means the opportunity to better understand the machine operation, provided there is enough context to enable an understanding of the data.

For example, a piece of equipment may be running hotter than usual because it is running harder, under greater load or because the ambient temperature is higher that day. Startup performance will vary based on a cold or warm start. If a machine isn’t properly instrumented for context, making sense of data will be more challenging. This also requires a loosening of alarm levels, which is the early warning system to machine failures.

A common backbone enables the introduction of more sensors. These sensors might be unrelated to the machine’s operation, but they are critical to understanding the context of a machine’s operation.

3. Adding capabilities that can deliver a competitive advantage.

As a machine user, competitive advantage is making the product as efficiently and of the highest quality as possible. A smarter machine will certainly help. As a machine builder, what is the competitive advantage? In an Industry 4.0 world, competitive advantage may well be in the machine analytics the user can provide.

Users should also ask many questions for better insights such as:

• Is maintenance is being scheduled based on operations or a scheduled timespan?

• Are you able to view similar machines and identify which will provide the best rate of return and schedule appropriately?

• Are you able to connect remotely and have access to enough data and context, to properly troubleshoot a machine and eliminate the need for travel and coordinated visits?

• Can you add sensors to unlock a greater understanding to the operation of your machine, when needed?

• Are you delivering digital twin analytics, modeling machine operations and dynamically adjusting alarm levels based on the current context of operation?

Industry 4.0 technologies are unleashing waves of innovation that will increase performance, improve quality and reduce costs. With new technology such as Ethernet TSN, machines will shift from their original designed for purpose delivery to those that can offer quantified performance, quality and cost metrics. This will improve over time, based on original equipment manufacturer (OEM) analytics and feedback.

TSN market opportunities

TSN is recognized across different sectors as the future of industrial Ethernet and industrial communications. Technology companies have delivered silicon and firmware to enable the development of new TSN-based devices and infrastructure components. Leading automation suppliers have already adopted those new components into their automation equipment offerings, including PLCs, input/output and motion controls.

Proof of concepts have been on display for several years now at trade shows around the world, demonstrating new levels of motion control determinism that leads to higher quality products. Users can now combine video and deterministic control communications on the same wire.

This technology trend offers potential opportunities for machine designers and builders. By selecting state-of-the-art products with TSN capabilities, machine designers can increase their market coverage and gain a competitive advantage.

To tap into this market, machine designers are selecting products from leading suppliers to produce TSN-based solutions. Thanks to software and straightforward hardware modifications, it is often possible to update existing industrial controls to support next-level capabilities.

To enable future-proof industrial communications and next-level performance, machine designers and builders should think outside the box and embrace this new technology, ahead of their competition, to achieve a clear and measurable competitive edge. They need to act now to deliver TSN-compatible products or upgrade existing machines with TSN capabilities. By doing so, they can help their customers to create factories of the future while enhancing their own competitiveness in a fast-growing market.

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