OPC UA facilitates access to machines and data

The ‘Open Platform Communications Unified Architecture’ (OPC UA) standard is becoming increasingly established in machine and plant construction. The open interface standard is intended to define the mechanisms of cooperation in the industrial environment. It enables machine and plant construction to digitally network production with the help of IT.

Machines and plants can thus be redesigned as needed via Plug & Work – regardless of which manufacturers the machines and components in production come from.

Find out more in a conversation with Thomas Krainz (Industrie Informatik) and Stefan Hoppe (OPC Foundation).

“OPC UA is a framework for industrial interoperability. This means that you can use it to exchange data and its meaning – i.e. information – via interfaces in a standardised way,” said Stefan Hoppe, OPC Foundation Global Vice President. “It’s like a USB connector – it allows machines, devices, services and their interaction to be described. Ultimately, OPC UA reduces software engineering costs. Currently, operators such as Volkswagen, Miele and others are pushing for mandatory adoption, thus increasing the pressure for widespread adaptation of the standard.”

Another major advantage is also the significantly improved security: OPC UA was developed under the aspect of ‘security by design’. “This has been confirmed by the Federal Office for Information Security. Mechanical engineers have special core knowledge in their domain – but often not in IT security. So it makes sense to use a transparent standard that has been validated and is consensus,” Hoppe continues.

Easier communication and increased efficiency

Thomas Krainz, member of the management team at the MES provider Industrie Informatik and responsible for ‘Strategic Product Management’, relies on an integrated OPC UA server. “While the use of OPC technology has so far focused on the one-way transfer of data from the machine to IT, we are going one step further with the cronetwork MES solution. By means of an integrated OPC UA server, the transfer of data to a wide variety of recipients becomes possible.”

Krainz sees clear advantages for all involved through the uniform use of the OPC UA standard: “As an IT company, we have easier communication in the projects, and efficiency also increases. In the future, automation and control specialists can also take care of other things in the projects and don’t always have to work on individual interfaces.”

For machine builders, data access will become easier for different systems and service providers. In the future, this could lead to further additional services and services for the machines. “New services are emerging around the standards – and not just from an MES provider’s point of view.” Easier data access will also make communication and integration easier for everyone. Finally, on the customer side, there would be time and cost savings in implementation and ongoing operation.

Adaptation most advanced in Europe

According to experts, Germany in particular and Europe in general are ahead of the international competition in terms of acceptance and use of OPC UA. Stefan Hoppe comments: “I see the adaptation in Europe as the most advanced, the Industry 4.0 initiative has given a huge boost. The VDMA recognised at an early stage that the standardised description of data and interfaces and their significance are the most important things for the implementation of Industrie 4.0 and the Industrial Internet of Things.”

Thus, so-called ‘OPC UA Companion Specifications’ are currently being created at the VDMA in 15 different specialist groups of member companies in the areas of robotics, injection moulding machines, intelligent cameras, etc. – with the task of defining standardised data and interfaces. “VDMA is also coordinating these groups with each other to avoid overlaps, which is a Herculean task. Other countries are looking at these activities to adopt them as quickly as possible,” Hoppe continues.

MES expert Thomas Krainz also sees this pole position: “Especially in the DACH area, OPC UA technology is being pushed strongly and has established itself. These three countries are characterised by standardisation and ongoing optimisation.” The initiatives launched around Industry 4.0 by politicians also underline the relevance of OPC UA.

Delivering data in real time and on an order-by-order basis

If current surveys are to be believed, the topic of ‘standardisation’, as already indicated above, is probably the greatest challenge in the implementation of Industry 4.0 measures. Especially with regard to machine communication, there is a wild conglomeration of communication protocols and drivers. Plant-specific individual solutions are the order of the day. With cronetwork MES, the software provider Industrie Informatik breaks this circle and relies on standard communication in the machine environment with an integrated OPC UA server. This means that data and information can also be returned to the shop floor via the OPC UA server. The aim here is not to take over the machine control, but rather to comprehensively capture data, including machine and operating data, and then pass it on in compliance with the OPC communication standard – to a wide variety of recipients along the entire value chain. The possible areas of application and scenarios are correspondingly diverse.

Security, safety and investment security

It is in the nature of things that, with all the efforts around OPC UA, questions also arise about aspects such as security, safety or investment security: “OPC UA has built-in security mechanisms at various levels such as transport, information access and the application, which naturally also has a positive influence on the topic of IT security,” says Stefan Hoppe.

Recently, a separate group was set up at the OPC Foundation to deal intensively with the topic of ‘functional security’. “As far as investment security is concerned, the following can be said: since OPC UA is a framework – i.e. much more than just a protocol – further protocols can be added for the future,” Hoppe continues. However, the actual value of the standardised data and interfaces remains, and that is exactly what machine builders appreciate.

For Thomas Krainz, one thing is certain: “Above all, investment security is essential. Because the independence from special suppliers and providers is guaranteed by the new standards. In the CRM area, completely new business models can emerge as a result.”

But OPC UA is not just dreams of the future for many companies, but already lived reality, which could be implemented and realised in many projects: “Because in the past without standards many projects already got bogged down in the idea (for cost reasons, for example), many solutions were not implemented. Today, however, we can develop our MES solution properly because with OPC UA we have easier access to machines and the associated data,” reports Thomas Krainz. This development essentially extends across the entire IT sector.

OPC UA PubSub specification

OPC UA continues to develop in order to be able to cover further areas of communication. Thus, the OPC Foundation published the ‘OPC UA PubSub Specification’ in the spring of this year. This extends the previous field of application of a 1:1 confirmed communication with an unconfirmed broadcast approach. “PubSub enables the further adoption of OPC UA in the smallest embedded devices, which require optimised communication with low power and low latency in local networks,” explains Stefan Hoppe.

“On the other hand, the PubSub implementation via MQTT (Message Queue Telemetry Transport) also enables the use of OPC UA in highly scalable and cloud-based applications, where a virtually unlimited number of edge data sources – such as sensors – can securely deliver to internet-based broker applications over public wide area networks (WANs),” says Hoppe.

Distribution of tasks not endangered by OPC UA

For Krainz, the VDMA’s efforts are very positive because they also involve the machine-builders. Basically, all the efforts of the associations are very positive and worth mentioning. “However, the technology for machine builders should not be blown up too far,” warns Thomas Krainz of MES specialist Industrie Informatik. There are already complaints here that the OPC UA standard can do more and more and that one can no longer completely follow IT developments on the machine builder side. “You therefore have to be careful that the complexity does not increase even more and remains solvable. Otherwise, the standard would then fail quite early.”

Krainz also does not see the distribution of tasks among the users of the OPC UA standard endangered: “The core competences of mechanical engineers are closer in our direction when it comes to mechatronics topics, but a mechanical engineer still does not become an IT company because of that.” Acquisitions can be observed, but this does not mean that experience and know-how are also bought. “The whole thing is a question of core competencies that cannot be arbitrarily shifted back and forth between hardware and software overnight,” concludes Krainz.