There has been a lot of movement in the cloud provider market for some time now: A large number of providers are entering the market - with their own infrastructure or platform solutions as well as cloud services for machines and systems. A segmentation of the market can be observed more and more: Increasingly, mechanical engineering companies and component manufacturers are also offering their own cloud-based systems and services. In some cases, these require component or machine data or even access to machine functions to be available to the respective manufacturer in order to provide the service.

DIN SPEC 92222: a reference model

It is now becoming increasingly necessary to build a consensus for communication and data exchange between field devices and the cloud systems. This consensus building is referred to below as 'industrial cloud federation'.

From a technical perspective, industrial cloud federation encompasses communication from field or edge components to the cloud of a system operator as well as in the opposite direction. On the other hand, industrial cloud federation also describes cross-company communication between different cloud systems (technological) or cloud systems controlled and/or operated by different companies (organizational).

DIN SPEC 92222: It is intended to answer a whole series of questions for the respective interest groups.

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Rapid provision of the standard to the public is necessary in order to implement data-driven applications and innovative new business models cost-efficiently and to enable investment security for all stakeholders involved. An agile standardization approach in the form of a DIN SPEC was therefore chosen.

29 institutions are currently involved in the development of the DIN SPEC: 22 companies - industry giants and SMEs from all the stakeholder groups mentioned, four associations and three research institutes of the Fraunhofer Gesellschaft. In order to achieve the ambitious goals, the following in particular

• collect and prioritize concrete use cases from the workshop participants that are related to the Industrial Cloud Federation
• determine the standardization requirements for implementation
• define the solution patterns for implementation
• and evaluate the content of the standard.

The role of OPC UA

As part of the activities of DIN SPEC 92222, particular attention will be paid to minimizing the number of technologies, norms and standards to be used. DIN SPEC 92222 focuses exclusively on the area of Industrie 4.0 - manufacturing, production, mechanical and plant engineering - and will be integrated into the existing standardization landscape and recommendations of relevant committees.

In this context, OPC UA represents a promising starting point for Industry 4.0 - not least because OPC UA has been recommended by the Industry 4.0 platform and defined as a prerequisite for Industry 4.0 components. As part of the work on DIN SPEC 92222, the OPC UA standard was intensively examined with regard to its suitability for the Industrial Cloud Federation. One of the key findings: Telemetry - the transmission of measured values to a cloud - is already covered within the OPC UA standard at a solid level of maturity for Industrial Cloud Federation. As part of DIN SPEC 92222, aspects such as the routing of data across cloud systems must now be examined in more detail. The situation is different for functionalities that go beyond telemetry, such as access from the cloud for querying the OPC UA information model or calling methods. There is a need for standardization for the industrial cloud federation here.

OPC UA is independent of a specific transport protocol and can therefore be used on the basis of different protocols - TCP, MQTT or AMQP. The standard also evaluates and defines which transport protocols should be used for which application.

The LNI 4.0 Cloud Testbed

The 'Cloud2Cloud' testbed was initiated in collaboration with the Labs Network Industry 4.0 to ensure the practical suitability of DIN SPEC 92222. Here, various partners are testing specific use cases for SMEs in a pre-competitive environment in order to implement the new standard and associated framework conditions in practice in a cost-effective and low-risk manner.

DIN SPEC 92222 is expected to be published in the first quarter of 2019 and will be available to download free of charge from Beuth Verlag.

Authors:
Filiz Elmas is Project Coordinator Digital Technologies, Digital Technologies Department at DIN;
Dr. Christoph Legat is a software professional at Expleo in Germany.