Industrial Ethernet’s value for communications

Picking the right industrial Ethernet protocol for communications can give vendors, original equipment manufacturers (OEMs) and system integrators an advantage.

By Thomas Burke September 9, 2022

Courtesy: CC-Link Partner Organization

Learning Objectives

There are many Ethernet protocols designed for different purposes.
Time-sensitive networking (TSN) allows devices and applications that communicate on the multitude of industrial Ethernet protocols.
TSN makes information technology (IT) and operational technology (OT) convergence easier.

Ethernet Insights

Ethernet can help manufacturers in many industries get a leg up if they use the right communication protocol for their applications.
Industrial communications and information that flows with it are among the most valuable commodities any company can have. Wielding that info and transmitting it quickly and safely is critical in today’s fast-paced factories and industrial process environments.

Product vendors in the industrial automation space are always looking for a competitive advantage, and communications have always been a differentiator. From the early fieldbus wars to the current variety of Ethernet-based protocols, communications are still at the forefront for disparity. Users might think Ethernet must all be about the same, but consider the following.

Ethernet has become pervasive, and for good reasons. The size and strength of the information technology (IT) world is creating cost effective and high-performance products that should be applied in the industrial world. End-users’ expectations are that products should work out of the box and everyone is concerned about security and most important end-to-end data reliability. With cybersecurity a ubiquitous concern, there are many hardware and software solutions to develop and reuse for industrial grids’ safety and security.

Industrial Ethernet protocols by products, applications

Various industrial Ethernet protocols are designed for different purposes. The solution used depends on the vendor selected and the application products are being applied to. Often the products chosen mandates which industrial Ethernet protocols are to be used. Protocols are the technology behind the scene, getting the job done, and rarely is there a need to be familiar with the inner workings. Some protocols are designed to be high performance, others focus on communication efficiency and some are designed for client/server or publish/subscribe architectures.

We need these Ethernet communication protocols to get data from many disparate devices. OPC UA also is a communications mechanism to facilitate data modeling and information transfers, and it is important that all the industrial Ethernet protocols work seamlessly with OPC UA.

What is TSN technology?

Ethernet, managed by the IEEE under the IEEE 802.3 group of standards, continues improving. In 2017, the organization released the IEEE Standard for Local and Metropolitan Area Networks –Timing and Synchronization for Time-Sensitive Applications. Time-sensitive networking (TSN) allows devices and applications that communicate on the multitude of industrial Ethernet protocols and commercial networks to coexist on the same physical wire. This opened the door for the convergence of operational and IT networks. Benefits include:

Simplified architectures by having all devices share one wire.
Reduced cost due to simplified networks.
Easier management by offering device accessibility from IT networks.
Enhanced reliability through the categorization/prioritization of traffic.
Accelerated digital transformation by exposing data from control elements.

These are fundamental features within highly competitive and future-proofed smart factories.

TSN technology, which had its beginnings with audio-visual and automobile applications, was recognized as helpful for industrial use. The industrial marketplace needed a way to have determinism, high performance, and data reliability all guaranteed. At the same time, it was necessary to have multiple commercial off-the-shelf Ethernet protocols and industrial Ethernet protocols being managed and coexisting on the same physical wire.

Ethernet-based protocols and communications are still at the forefront for disparity. Fast industrial network needs are met with CC-Link IE TSN, the first open industrial Ethernet that combines Gigabit bandwidth and TSN functionalities. This is especially useful to meet Industry 4.0 requirements. Courtesy: CC-Link Partner Organization

How does TSN work? Multiple networks, determinism

TSN is a standard-based technology that sits at Layer 2 – Data Link of the OSI model to expand capabilities of current Ethernet networks. TSN is described by the IEEE 802.1 set of Ethernet sub-standards and focuses on delivering determinism and convergence of multiple data traffic streams on one network. Two important TSN sub-standards that provide such abilities are IEEE 802.1 AS and IEEE 802.1 Qbv.

The first ensures that all devices on a network are synchronized, providing the basis for determinism. Once a shared sense of time is in place across a network, IEEE 802.1 Qbv defines “time aware shapers” These define specific “time slots” that are assigned to different types of network traffic, which are prioritized according to the information carried. As a result, different types of data traffic can all travel across the network in a predictable way, further supporting deterministic communications. This method supports convergence of multiple traffic types and the ability to combine operational technology (OT) and IT worlds.

TSN from an end-user perspective

The industrial automation marketplace is an ecosystem of end users who specify projects to machine builders who in turn look for vendors that can offer products and solutions that meet those specifications.

A key benefit for end users – original equipment manufacturers (OEMs) and system integrators – is providing a simpler network architecture and corresponding machine designs to enable them to have the mix of applications and devices peacefully coexisting. The biggest challenge that OEMs and system integrators face is how to configure and manage the integrated solutions and then pass this knowledge to the end users who maintain and use machinery. Simplified architectures and easily manageable devices are a key benefit.

Industrial Ethernet organizations all want to have their protocols work and configured and maintained as easily as possible. Adopting these industrial Ethernet protocols depends on ease of use, reliability, performance and being able to implement complex operations like motion and safety.

Industrial communications interoperability

Suppliers want to build products that work. Users want to buy products, understand the concept of multivendor interoperability and use products from different vendors independent of the networks and technologies they run on. It’s expected that devices and applications for industrial and commercial operations run seamlessly on the same physical wire. It’s a basic assumption commercial applications should not impact the industrial OT applications with respect to control.

Then there is OPC UA. OPC UA is not a protocol, but an OPC UA effort called field level communications (FLC), leverages TSN technology to run complex applications. Data and information integration between IT and OT is now a byproduct of TSN technology. The OPC Foundation is collaborating with industrial Ethernet organizations to leverage TSN and to coexist in homogeneous fashion with disparate applications and networks.

The convergence supported by TSN strengthens data transfer across the enterprise allowing end users to have much greater process transparency. Transparency is all about being able to extract more data from industrial applications and devices, analyze this data, and transform it into meaningful information to better maintain and fine tune operations. The result is the information that can be leveraged and provide the necessary insight to optimize performance, productivity and efficiency, resulting in improved product quality.

The message becomes that bandwidth is important, but even more so with interoperability. Users can be assured systems can communicate with each other and industrial control can continue without interruption.

Thomas Burke, global strategic advisor, CC-Link Partner Organization, a CFE Media and Technology content partner. Edited by Chris Vavra, web content manager, Control Engineering, CFE Media and Technology, cvavra@cfemedia.com.