The aim of communication between production machines is to collect data for further processing and evaluation. This is what makes aspects such as predictive maintenance or optimizing machine utilization within the production environment possible in the first place. This is where the OPC UA (Open Platform Communications Unified Architecture) standard can be seen as an opportunity and used as a compatible solution for all systems.

M2M communication is traditionally based on fieldbus technology. Classic fieldbus protocols such as Profibus or Modbus RTU have been in use for many years, are mature and widely used in network technology. The best-known Industrial Ethernet protocols are Ethernet/IP, Modbus TCP, Profinet and Ethercat.

However, the increasing spread of the 5G mobile communications standard will also influence and accelerate developments in the field of M2M communication, as the use of 5G replaces the physical networking of machines. Here in particular, there is clear potential to use the new possibilities of wireless networks to further advance the digitalization of the industrial environment.

OPC UA as a future-proof solution for automated communication

All components that are to be used for automation must support the established and widely used fieldbus protocols, but must also be compatible with Industrial Ethernet and the TCP/IP protocols commonly used in IT. At this point, innovation topics such as big data, predictive maintenance and the fact that classic IT systems are also increasingly becoming part of the automation landscape in industry come up again and again. But how can these requirements be met in the future and at the same time satisfy other requirements in the smart factory sector?

This is where OPC UA comes into play. OPC UA is already being used as an overarching architecture to ensure the necessary exchange of information between manufacturers and the interoperability of the various components. In this context, OPC UA is far more than just another communication standard for real-time communication in automation. Rather, OPC UA is a service-oriented architecture (SOA), based on an IP-based network and compatible with both IPv4 and IPv6. In addition, OPC UA is platform-independent, flexible to use, future-proof and can be expanded as required.

The independence of the physical transport medium and protocol should be particularly emphasized - which is a decisive advantage of OPC UA over other dedicated IoT data protocols.

"PubSub" standard enables communication down to sensor level

The OPC Foundation creates the necessary standards and cooperates with market leaders from the industry in order to always be able to meet the latest developments. For example, it has also published the Publish-Subscribe Standard (PubSub) for OPC UA as an important extension of the communication standard.

This standard is fully compatible with existing OPC UA technology and allows users to roll out OPC UA down to the lowest level of production, where controllers, sensors and embedded systems require optimized communication with low latency in local networks.

Standardized communication with DIN SPEC 92222

The aim of DIN SPEC 92222 "Reference Model for Industrial Cloud Federation" is standardized communication from the field device to the multi-cloud application based on OPC UA. Well-known companies such as Bosch, IBM, Fujitsu, Microsoft, Fraunhofer research institutes and the VDMA and Bitkom associations are involved.

Various approaches are defined to achieve this goal:

• Minimizing the number of technologies, norms and standards to be used,
• standardized interfaces for routing between the clouds as a prerequisite for a multi-cloud infrastructure,
• determining which transport protocols should be used for which application,
• Specific implementation determines how, for example, the configuration and provision of necessary components (e.g. brokers, relays or routers) is to be carried out,
• Creation of specifications for uniform authentication and authorization.

OPC UA is constantly being developed further. Thanks to the high level of acceptance - by manufacturers and the entire industrial sector - OPC UA is currently the most widely used, platform-independent communication standard to ensure interoperability and information exchange between machines and systems. With over 610 members of the OPC Foundation and thousands of OPC UA-compliant devices, OPC UA offers a future-proof framework for M2M, Smart Factory and Industry 4.0.

Christian Gügel, Senior Systems Engineer at Paessler