Mr. Hoppe, at SPS IPC Drives 2015 you announced that you would be tackling the topics of open source and publish/subscribe for OPC UA. How far have the plans progressed?
Hoppe : The open source announcement has already been implemented: We are already making the C# and Java sources available on GitHub, with the AnsiC version to follow. The opening up was an important step to promote evaluation in the IT sector in particular.

The publish/subscribe extension of the existing client-server communication is extremely important for the optimized message flow in sensor and cloud networks. The working group responsible for this is very active with 42 well-known companies. The companies Beckhoff, B&R, Bosch Rexroth, CAS, Honeywell, IBH-Softec, National Instruments, Real Time Automation, Sick, Softing and Unified Automation are already demonstrating an initial implementation at the Hannover Messe 2016.

At the end of last year, you also set up a working group dedicated to Time Sensitive Networking - TSN for short. What is the status quo there?
Hoppe: The combination of TSN and OPC UA raises high expectations! More than 40 companies are also active in this working group, fortunately including many companies from the network sector that were not previously members of the OPC Foundation - I would like to mention Cisco in this context. However, it was still too early for a live demo at the trade fair. This is mainly due to the fact that standardization for TSN itself is not yet complete. However, initial results have already been incorporated into the underlying OPC UA PubSub specification. One focus of the working group is now to coordinate the requirements of OPC UA for the configuration of TSN with current TSN standardizations - for example at the IEEE.

At the press conference in Hanover, Thomas Hahn was the first Siemens representative on the speaker's podium, who emphasized the support for OPC UA. What signal effect do you expect this to have?
Hoppe: What many people don't realize is that Siemens is the European founding member of the OPC Foundation, a member of the OPC Board from the very beginning and the annual organizer of the Interoperability Meeting in Nuremberg. Siemens has also worked intensively internally on integrating the technology into a wide range of products - today you can already find OPC UA in nine different device categories from Siemens, including S7 controllers and drives.

With Matt Vasey, you have now elected the company Microsoft to the board of the OPC Foundation ...
Hoppe: ... which means that we have another major IT provider on the board alongside SAP - and that's important. After all, although OPC UA technology originated from the requirements in the field of automation, it scales beautifully from the sensor to the IT and cloud world and therefore also to other industries. The OPC Foundation shows that it has an international presence, brings IT and automation together and also delivers internationally with OPC UA as an IEC standard. - What other organization does this?

How serious is Microsoft about its OPC commitment?
Hoppe: Very seriously! Forward thinkers such as Azure architect Clemens Vasters recognized early on that OPC UA is more than just a protocol - it's a complete framework that ensures industrial interoperability and is also expandable. Vasters has been a member of the OPC UA Core technical working group and advisory board for two years and has made a significant contribution with his knowledge to the expansion of the OPC stack with Pub/Sub. The result: Microsoft is now the first cloud provider to have a direct OPC UA AMQP channel in the cloud! All current and future OPC UA servers can therefore communicate AMQP directly in Microsoft's Azure Cloud after the stack update. With the Publisher, Fieldgateway & Relay and other OPC UA services for visualization in the cloud, Microsoft is now delivering a total of four strategic OPC UA implementations in the Azure Cloud - some of them as open source variants. And last but not least, Microsoft is also making an OPC UA client available in open source as a Windows universal app - so the client runs on the Windows 10 cell phone and in the Hololense glasses. Who would have expected that! OPC UA from the sensor to the IT & cloud world is therefore a reality and is growing into a secure USB connector for software - the world protocol or Esperanto for machines!

OPC UA is becoming 'the' world protocol for machines! DDS is out of the race?
Hoppe: It makes no sense to fuel an imaginary competitive situation. In a joint paper by the OPC Foundation and the DDS-supporting Object Management Group (OMG), we recently described that OPC UA and DDS are actually in different sectors - DDS is more likely to be used in medicine and the military, while OPC UA is used in automation with all its facets. There are only a few fields of application in which OPC UA and DDS overlap - for example in the energy sector, but again with different applications. We have also described how a bridge functionality can bring together the applications from both worlds with their different requirements for common applications. There are essentially two variants: A mapping of DDS objects into the OPC UA namespace - as is already done by many other organizations such as Profinet, Ethercat, Powerlink, CAN, Sercos, IO-Link, CC-Link - or by extending the OPC UA Pub/Sub with a potential UA DDS in addition to UA-UDP, UA-AMQP. All in all, this demonstrates the potential technological extensibility of the OPC UA standard. As already mentioned, Microsoft recognized this extensibility early on and has already implemented it in products.

Incidentally, there is no reason why MQTT should not be integrated into the OPC UA stack as a pub/sub, there just needs to be an advocate and initiator. And the prophecy that this will happen is not exactly spectacular. This is because the smallest sensors, which only have extremely few kilobytes of resources, cannot host a complete OPC UA server. These devices will nevertheless send an OPC UA-compatible JSON directly - via AMQP or MQTT - in order to communicate seamlessly with the existing remote stations. OPC UA provides the meaning of the data, including access authorizations, and scales from the sensor to IT - also via AMQP and probably soon via MQTT.