Guest Blogs Industry 4.0 Internet of Things Technology

The Pioneers Of The OPC UA TSN Movement

tsn opc ua

Guest blog from Sebastian Sachse

When talking to industrial automation experts, it becomes obvious pretty fast that they have high hopes for OPC UA TSN. The hopes are based on concepts and technologies still under development. But this is about to change. The ability of OPC UA TSN to meet communication requirements from the field level up to the ERP level under real-world conditions has been proven by TSN network specialists. The way is paved for OPC UA TSN to become the enabler for Industrial IoT applications.

Intensive field testing with OPC UA TSN has revealed impressive results and even outperformed the expectations of automation technology experts. Usually time-critical applications at the field level, such as synchronization of conveyor belts with various other equipment, require cycle times as low as two milliseconds. TSN network specialist TTTech determined in a test installation that even lower cycle times are feasible. OPC UA TSN may even bring jitter down to less than 100 nanoseconds. Not only those low jitter times were impressive, but also the stability and auto configuration of the system during testing.

Testbed accelerates adoption of the Industrial IoT

Founded in 2014 by AT&T, Cisco, GE, IBM and Intel, the Industrial Internet Consortium (IIC) aims to enable the intelligent networking of machinery, equipment and facilities. The IIC organizes so-called testbeds, platforms for experimentation of large development projects, to identify which technologies are best suited to Internet of Things (IoT) applications. The test installation of B&R, IIC member since 2016, has been an integral part of the IIC’s TSN testbed since the beginning. The objective is to examine the interoperability of components on a multi-vendor network with TSN. The first protocol being tested with TSN in this testbed will be OPC UA. It is the first time that the majority of the automation market is working together in a harmonized, industrial environment targeting seamless integration of all components independently of the vendor.

Low resource intensity

Code size and resource requirements play a vital role for practical OPC UA applications. If OPC UA were only able to run on powerful industrial PCs and controllers, use in machinery and equipment would be out of the question. By implementing OPC UA on a bus controller from its X20 system, B&R has clearly demonstrated the feasibility of I/O-level applications for OPC UA. It proves that OPC UA is perfectly scalable to any conceivable task at the line level and beyond.

Reduced network traffic

An important new feature of the OPC UA specification is the publisher/subscriber extension (OPC UA pub/sub), which allows OPC UA TSN to achieve the necessary performance and optimizes cyclic communication. By implementing OPC UA pub/sub on a controller, B&R was able to test this model. It adds to the OPC UA communication via client-server mechanism, where a client requests information and receives a response from a server. On networks with large numbers of nodes, client-server traffic increases disproportionately and impairs the performance of the system.

client server model
The figure demonstrates the client-server mechanism (Source: B&R)

In contrast, the publisher/subscriber model enables both one-to-many and many-to-many communication. Server data will be sent to the network (publisher), which can be received by every client (subscriber). The advantage of this approach is that the need for a permanent connection between client and server becomes obsolete. Consequently, intensive network traffic can be brought to a minimum, which saves resources.

Responsible for the development of the specification for OPC UA’s publisher/subscriber model is the OPC Foundation working group, in which B&R is actively participating. The specifications are expected to be completed by the end of the year. Many manufacturers could begin rapid implementation soon thereafter.

tsn publisher subscriber model
Visualization of the publisher/subscriber model (Source: B&R)

OPC UA as a standard

There seems to be no doubt about it that the OPC UA movement is gaining traction. Organizations like EUROMAP are basing their work on the vendor-independent protocol. The leading developer of global standards for the plastics industry recently defined OPC UA as the basis for two new EUROMAP interfaces.

Another example of OPC UA’s increasing acceptance is OMAC, the umbrella organization for the packaging industry. OMAC is integrating OPC UA into its PackML standard and automation suppliers are working on implementations. It really is astonishing how quickly such well-established industry standards are now turning to OPC UA. The performance demonstrated by our field testing with OPC UA TSN confirms that they’re moving in the right direction.

For access to hardware or support with management and implementation of TSN standards, don’t hesitate to contact EBV TSN experts here!

Learn more about IEEE TSN standards here and learn how to get started here.

Learn more about B&R’s activities with OPC UA TSN here.

Author Bio:

Together with a global team, Sebastian Sachse is responsible for the technology marketing of Open Automation Technologies at B&R. In this context he’s representing B&R in the organizations such as the IIC, OPC Foundation and VDMA. Throughout the last eleven years he held several positions in the automation business and gathered experience as Support Engineer, Promotor for Industrial Solutions and Technology Manager. He graduated from the “Duale Hochschule Mannheim” as “Dipl.-Ing. (DH) Elektrotechnik”

 

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