OPC UA for Machinery: Interface description for the entire mechanical engineering


Extensive work is currently being carried out under the umbrella of the VDMA to standardize the interfaces of machines and components in individual sectors. In the "OPC UA for Machinery" Companion Specification all basic information models resulting from this work are combined.

The preferred standard for these future-oriented interfaces is OPC UA (Open Platform Communication Unified Architecture). OPC UA offers besides the technology the possibility to describe products and functions. This is done in the form of so-called Companion Specifications, which are specific to the industry. Currently, around 30 working groups within the VDMA are working on such Companion Specifications, and over 450 companies in the industry are involved in the preparation process.

Due to the central coordination within the VDMA, it turned out that some interface contents occur across industries. Accordingly, the idea was born to create a basic specification for the entire machine and plant construction. This base specification will be called "OPC UA for Machinery". On the one hand, this is to be used as a basic building block for existing and emerging Companion Specifications. On the other hand, machines or equipment of the mechanical engineering industry can use the contents of the specification if no standardized interface of their own industry is yet available.

"OPC UA for Machinery is the basic building block for Industrie 4.0 communication"

In order to enable early adaptation, content is developed and published in so-called building blocks. This reduces the development time and thus allows to use content that would otherwise not be public. In addition, depending on requirements, only certain or all building blocks can be used in the industry-specific Companion Specifications. This also applies to use without industry-specific companion specifications.

Procedure and working method
The working mode for creating "OPC UA for Machinery" differs from the usual procedure found in industry-specific Companion Specifications. First, a group of experts prepares a draft for each building block in the so-called core working group. The expert group is composed of specialists from various industries who have a high level of expertise in both OPC UA and mechanical engineering, especially for the addressed topic. At regular intervals, the draft prepared by the core working group is compared with the members of the overall working group. All members of the VDMA and the OPC Foundation are eligible to participate in the overall working group. As soon as the developed draft has reached a certain degree of maturity, the document is passed on to the OPC UA working groups of the VDMA for review. Only after the comments submitted in the VDMA internal review process have been processed, a Release Candidate will be given into the public objection phase.
Part I already published The first two building blocks have been available to the public in the form of a release candidate since the end of April. Each Building Block covers one use case. The first two use cases covered are:
  • Identification and nameplate of machines
  • Finding all machines in the server
In order to identify the next needed use cases and further requirements, feedback was gathered from the OPC UA working groups of the mechanical and plant engineering and manufacturing industries, as well as the Industry 4.0 community. These were collected and evaluated to create a plan of action for the next topics to be addressed. The work will continue seamlessly, so that further building blocks will be published continuously until the end of the project. The following use cases were identified as the next topics to be addressed:
  • Identification and nameplate of components
  • Machine status

Heiko Herden
VDMA Forum Industrie 4.0 / OPC UA
Phone +49 69 6603-1315
E-Mail heiko.herden@vdma.org