Communication technologies: supporting digitalisation

02 November 2020

Dr Peter Wenzel comments on industrial technology trends and the impact they are having on industrial communication solutions.

Digitisation can only be successfully implemented areawide in production environments if the communication systems can take into account big data requirements. Big data is served by various data sources, in particular also those that deliver during production with the participation of sensors and actuators. On the one hand, this requires a higher bandwidth with which the data generated in the production environment can be transported to the cloud. On the other hand, standardised data formats are required for an efficient and barrier-free exchange of information.

PROFIBUS & PROFINET International (PI) is already undertaking innovation projects that aim to increase both the bandwidth and the development of its technologies from a communication-related to an information-oriented technology portfolio.

The already available integration of TSN basic functions into PROFINET provides higher bandwidths due to the implicit opening for Gbit and forms the basis for the required interoperability of convergent networks. In process automation, there is a major innovation step with Ethernet-APL, which significantly increases the bandwidth available today. In addition, the move from Ethernet to the sensor level will enable a much more efficient exchange of information due to the associated standardisation of the protocol. Ethernet-APL uses Single Pair Ethernet (SPE), IEEE Std 802.3-2019 (10BASE-T1L), which enables cable lengths of up to 1,000m.

In factory automation there is already the IO-Link sensor communication protocol is already available. Today it allows for cable lengths of up to 20m and supports data rates of up to 230.4 kbaud for IO-Link device – master communication. The IO-Link experts recognised the potential of SPE for IO-Link and started an activity in which the new possibilities of SPE for the IO-Link ecosystem should be investigated. 

To implement the second factor, in cooperation with other organisations, PI has defined open and standardised semantics for the device description and the application-related data to be transferred. PI relies on OPC UA for horizontal communication between different controls and the vertical to higher levels. The data itself is supplied by subordinate IO-Link and/or PROFINET networks. In most cases, this already works on the basis of the TCP/IP protocol, which has been available for years and can be operated co-existently in PROFINET networks.

The transitions from PROFINET to OPC UA required further standardisation of the data formats in close cooperation with the OPC Foundation. The result is the OPC UA PROFINET Companion Specification, in which an OPC UA Information Model for the representation of the standardised object model of PROFINET has been defined. As a result, applications based on OPC UA services can access objects from PROFINET devices regardless of the manufacturer. Comparable information has been specified in the OPC UA for IO-Link Companion Specification. 

Big data
As a basis, big data requires a high degree of machine-processable, standardised information that is available across all companies and industries which can be used as the basis for a machine-processable data flow across the various systems from the sensor to the cloud. The data already available today must be converted into clearly usable information with the help of semantic standards. In cooperation with eCl@ss e.V., the parameters defined in the specification documents by PI are expanded to include semantic identifiers.

The measures described support operational technology (OT) in its automation task by providing open, standardised real-time functions for horizontal communication in the field. The open, cross-level data models are a necessary prerequisite for seamless vertical data transfer to IT for efficient production control, monitoring, analysis and optimisation in the Industry 4.0 era.

Dr Peter Wenzel is executive director of PROFIBUS & PROFINET International, Germany.

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