Time Sensitive Networking is a technology that will benefit device vendors, machine builders and end users.

For vendors: build devices that offer precise control of latency and jitter while being able to share networks with devices using dissimilar traffic. This will provide the key components of future automation systems.

For machine builders: design systems that are simpler, lower cost and easier to maintain, as the convergence enabled by TSN will allow all traffic to be handled by the same network.
For end users: benefit from the transparency delivered by these converged networks in order to gain better understanding of their processes and hence optimize them.

Benefits of converged networks

In the past, it was commonplace to have multiple networks, each dedicated to a specific task. For example, one would address general control, such as communications between PLCs, I/O and similar devices. Another network would handle communications for safety functions, such as emergency stops, light curtains, and safety controllers. There could also be a separate network responsible for motion control communications, connecting servos, drives, encoders, and motion controllers.

Getting these isolated setups to work together could be a significant engineering challenge. Time to market was slow, project timeframes were long, costs were high and maximizing performance could be an issue, along with maintenance.

To address these challenges, many modern-day industrial Ethernet technologies allow the combination of general, motion and safety control on one network, delivering substantial improvements.

However, Industry 4.0 is requiring end users to go beyond this. In order to address the challenges outlined in the overview, it is necessary for Ethernet to support the convergence of all kinds of networks and traffic types typically found in an industrial setting. Therefore, the integration of equipment such as barcode readers, vision systems and printers that may be using normal Ethernet networks without any specific industrial protocol also needs to be considered.

Moreover, it is commonplace for plants to evolve over time, with different projects using different technologies. As a result, many factories have multiple incompatible industrial Ethernet ‘islands’. Since it is often difficult to combine this dissimilar traffic to get the ‘big picture’, process transparency is hampered and hence optimization and management is difficult. As TSN will allow this dissimilar traffic to share the same network, these islands will become a thing of the past.

TSN also allows this to be taken one step further. As the concept model of Industry 4.0 matures, common IT technologies such as cloud computing are entering manufacturing.

While many cloud systems can theoretically absorb a large volume of plant data, in practice, it is not necessary for these IT systems to track every tiny detail of machine operation. This is why so called ‘edge servers’ have also appeared.

Their function is to act as a filter to transmit the most valuable data to the cloud, where it can be processed into information that provides the required process insights.

It is clear to see that network architectures that deliver a single converged stream of data to these edge servers will provide a more efficient base for operation and optimization. This is one of the main ideas behind ‘OT/IT convergence’ where ‘OT’ is Operational Technology, or the factory floor.