Phase #3 of OSADL project on OPC UA PubSub over TSN successfully completed

By: Carsten Emde

Another important milestone on the way to interoperable Open Source real-time Ethernet has been reached

Since 2018, Fraunhofer IOSB, Kalycito and OSADL have been forming a working group to create a publically available framework for real-time communication over Ethernet, based on OPC UA and TSN. The associated work was divided into several project phases. With the successful completion of phase #3 another important milestone has now been reached.

Phase #3 of the "Building an Open Source OPC UA over TSN Ecosystem" project received funding of €117,500 from participating companies. Specifically, these are the following companies (in alphabetical order):

• ABB
• Arm
• B&R
• Intel
• Kontron Europe
• Siemens

 

In addition, the following companies provided funding in the previous two project phases:

• Balluff
• Heidelberger Druckmaschinen
• Linutronix
• Nestfield
• Pepperl+Fuchs
• Pilz
• SICK
• TQ-Systems
• WIKA Mobile Control

The software developed within the project concerned the OPC UA stack open62541, publisher and subscriber applications for PubSub as well as installation and configuration scripts for TSN.

1. OPC UA stack open62541

The OPC UA stack open62541 has been successfully developed further and has meanwhile become the second most used OPC UA stack worldwide. After the successful certification according to the "Micro Embedded Device Server" profile, the certification according to the "Standard UA Server" profile is now aimed for, for which meanwhile about 80 to 90% of the requirements are fulfilled. Successful certification to this much more advanced profile is expected in the next few months.

2. PubSub security

An outstanding achievement in this project was the complete implementation of an encryption layer, so that the requirements for PubSub security are now met.

3. TSN

With the help of a Quick Start Guide under an Open Source license that was developed as part of the project, interested individuals can test set up an OPC UA PubSub connection over TSN and perform their own performance tests between two Intel systems that are equipped with a standard Linux distribution. The included instructions explain the steps to set up real-time Linux and to run examples of publisher and subscriber applications on one of the two systems respectively. These applications use bandwidth reservation and timestamp-based transmission of network packets, and the maximum latency between the theoretical and the actually measured arrival time of the network packets is provided as result. If the systems are correctly configured, the measured latency is of the same order of magnitude as the system latency (see 30-hour latency recording below); this proves that an ideal real-time Ethernet connection was created. Thus, the real-time Ethernet set of methods that OPC UA PubSub over TSN provides qualifies as a worthy Open Source successor to the existing predominantly proprietary protocols and for the first time opens up novel end-to-end communication concepts from the sensor to the cloud.

The above-mentioned companies participating in the project have thus made a significant contribution to the technological progress of the automation industry, which is recognized and appreciated on many occasions.

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