Although all industrial sectors are still a long way from the ideal state outlined by the term Industry 4.0, a faster implementation of digitalization strategies can be seen, especially in industries that deal with consumer-oriented products, solutions and services. One reason for this is that consumer-oriented products generally require more customer-oriented individualization. Secondly, the risks to people and the environment posed by these manufacturing operations are often orders of magnitude lower than the risks that need to be safeguarded against when operating large-scale chemical plants, for example. And last but not least, consumer-oriented products and services are subject to greater pressure to change - product life cycles are significantly shorter.

But what does this mean for process automation and process sensor technology if it is installed in large-scale plants such as chemical plants or in the oil and gas industry? Representatives of NAMUR - the international association of users of automation technology in the process industry - make a clear statement on this: The actual process automation, which ensures the safe and efficient operation of the systems, should not be changed lightly. Proven operation and technical suitability for operation in the harsh reality of the process plant are therefore indispensable components of process automation.

The structure of the asset administration shell as well as the original and the additional high-performance digital interface. The additional interface can initially be implemented as a genuine additional physical interface.

© Pepperl+Fuchs

Other NAMUR representatives have taken up this idea and propose an implementation of the asset administration shell described in the results paper of the Industry 4.0 platform (BMWi 2016) that takes this idea into account. According to this, an OPC/UA server is implemented in each field device - especially the process sensors - which exchanges all parameterization and diagnostic data with an OPC/UA client implemented in the externally 'hosted' administration shell during the entire operation of the field device. The field device also receives an additional digital wireless or wired high-performance interface. All additional new digital applications are supplied via this parallel infrastructure. At the same time, the original interface to the control system remains unchanged. The additional interface can initially be implemented as a genuine additional physical interface. Wireless HART, for example, is a solution available today.

Wireless data transmission

In addition to the existing 4 to 20 mA interface, which provides the connection to the control system, a wireless HART adapter is subsequently added to the device. The wireless transmission of HART data allows all parameter and diagnostic information from the field device to be recorded throughout its life cycle. The HART-capable 4 to 20 mA field devices already installed today can be easily extended with a digital interface, but the conversion to OPC/UA must then be carried out in the administration shell.

A subsequently integrated wireless HART adapter allows all parameter and diagnostic information from the field device to be recorded and transmitted wirelessly throughout its life cycle.

© Pepperl+Fuchs

In a similar way, sensors and actuators equipped with an I/O-Link interface, for example via 'SmartBridge' adapters from Pepperl+Fuchs, can be equipped with an additional digital interface. If necessary, an OPC/UA server can be embedded in these adapters.

The disadvantage remains that this second interface and the associated infrastructure mean further investment and additional engineering. These additional costs must either be amortized through additional efficiency and productivity gains or even enable completely new business processes - with corresponding earnings potential - in the first place. For this reason, wireless HART or 'SmartBridge' will probably remain bridging technologies that are only used selectively or at least not across the board.

Consequently, the asset administration shell model as a field device data manager for applications outside the classic automation pyramid will only become interesting for broad applications if the next generation of field devices has a single physically implemented, high-performance interface that supplies both the control system and the new digital applications with data.

The virtual interface

The second interface is therefore only implemented as a logical, virtual interface. It therefore makes sense to equip future field devices with only one IP interface and to represent both real-time capable control and process monitoring as well as new digital applications and various services via an OPC/UA server. A group of manufacturers, including Pepperl+Fuchs, has therefore set about developing an IEEE-standardized IP communication physics (APL) that primarily takes into account the requirements of process automation. Together with the intrinsically safe electrical power supply, IP communication is to be made possible via just two wires over a cable length of up to 1000 m. The requirements of the NAMUR position paper "An Ethernet communication system for the process industry" from February 2016 are fully taken into account. The first implementations are currently not expected before 2018.

It is certainly not too bold a vision to assume that all field devices will be directly connected to the Industrial Internet of Things via such an IP interface in the future. The automation pyramid will then be fully mapped in the RAMI 4.0 reference architecture. The control system, programmable logic controllers and other control and monitoring systems can then also be integrated into these networks and, if necessary, new applications can be allocated in the cloud.

Author:
Dr. Gunther Kegel is Chairman of the Management Board of Pepperl+Fuchs in Mannheim.