Interface standard Flexibility is important for a market-capable standard
Dr. Alexander Broos is in charge of research and technology at the VDW. In an interview, he explains which global challenges must be overcome in implementing a new, uniform OPC standard.
The development of umati (universal machine tool interface) as an internationally recognised standard interface is progressing ever further. This demands know-how from all participants and initiators. For, on the one hand, the OPC UA specification for machine tools has to be maintained; on the other hand, the necessary prerequisites and adaptations have to be supplied for the machines and control systems of the participants.
Dr. Broos, what stage has umati reached?
At the moment, we are working on something like umati 1.0. There will certainly be further developments, as is usual for software in the context of practical applications. At some point there will be umati 1.1 or umati 2.0. Realising this for all the norms and standards involved is a complex process. In concrete terms, we have to react to changes, if necessary also with an update. And we have to decide how downwards compatibility is to be realised.
Is umati a rival for the US standard MT-Connect?
Both umati and MT-Connect are open interfaces. Umati relies entirely on the freely configurable OPC UA as a communications platform. OPC UA creates a framework with clear rules for how machines correspond with each other. The precise content of the communications has to be determined individually by defining parameters in an OPC UA companion specification, which represents something like a “dictionary”. In the effort to work out a unified dictionary, harmonisations are also taking place between umati and MT Connect. As far as implementation is concerned, however, there are some differences. In this regard, umati is aiming to build on special domain knowledge in the machine-tool industry for a focused realisation of semantics and the information model.
What role is the VDMA playing here?
The OPC Foundation has signed a cooperation agreement with the VDMA (Federation of German machine and installation builders). This means that, for all sectors in machine and installation construction, the VDMA functions as the German and European platform, and as a strategic partner of the OPC Foundation. Firms wishing to implement the OPC use the so-called sector-structured VDMA uniformity sheets. In particular, the VDMA specialist groups for robotics + automation and for plastic and rubber machines have of course already developed a standard of their own. Other groups, such as the makers of packaging machines, are also working on this. We in the VDW, with our own sector initiative, are therefore working in a very competent environment, are involved in the developments at the VDMA, and in the long term can profit from the synergies developed there.
What does this diversification mean for manufacturers in the individual sectors?
Sector-specific standards are of course also important for OPC UA, indeed inescapable. The differences are too great between the various sectors. Furthermore, there will also always be manufacturer- or customer-specific requirements for data which cannot be standardised in the first place. Nevertheless, there will also be a certain constant component across all sector boundaries. The aim is for this component to be represented as an information unit of the greatest possible general validity, equally applicable in all sectors. The relevant harmonisation takes place at the VDMA. When one considers the joint goal of the most generally valid and broadly applicable standard possible, of course, this process demands a certain flexibility from all participants. I am however optimistic that we will move forward together relatively quickly towards this goal.
“We have to react to changes, if necessary also with an update.” - Dr. Alexander Broos, VDW.