From the fieldbus to ERP

Food production involves more than just 'good taste', as economic effi-ciency also plays a major role. Besides a range of other factors, manufacturing processes require a high degree of automation that makes it possible to maintain consistently high levels of quality for each charge and ensure efficient production. As a result of the horizontal and vertical integration of automation systems at food companies, managers are now setting their sights on the entire value chain, which typically extends from the production of a product out of the raw materials supplied to the product's filling, packaging and delivery.

Real-life food production facilities always contain a mix of different automation systems. While motion control systems, robots and PLCs are being used to automate internal logistics processes and packaging machines, process control systems manage the actual production steps.

Fieldbuses are gaining ground

Automation primarily involves collecting and processing information at the production level (field level) and using the appropriate methods to allow this information to act back on the process. The 'field' consists of the sensors and actuators that monitor and control the technical process. In line with the development of bus-compatible sensors and actuators and standardised fieldbuses, the horizontal integration of controls and field devices has proceeded in stages since the 1990s.

Bus systems such as Profibus-DP, Interbus and Foundation Fieldbus do not only reduce the amount of wiring required, they can also be easily expanded. In addition, they improve a system's immunity to interference because the signals are transmitted from the facility in series instead of in parallel. As a result, a single cable suffices to establish a connection between the controls and the sensors/actuators.

The ethernet has reached the field level

Thanks to its higher transmission rates, diverse range of IT services and new functions such as wireless LAN, the ethernet is increasingly expanding into the domain formerly reserved for fieldbuses.

The PC, which was originally designed for offices, is now increasingly common in industrial facilities as well, where it augments the previously dominant programmable logic controllers (PLCs). Whereas only one out of four machine construction companies used ethernet networks to establish a connection to a PLC in 2001, this share has increased to nearly one out of two in 2005. And one out of eight PLC users plans to purchase their first industrial PC, with experts expecting a trend towards panel PCs.

Wireless LAN, in turn, opens up additional opportunities which are very difficult to exploit with conventional bus systems. WLAN can be used, for example, to connect nearly inaccessible components without requiring any wiring. What's more, portable PCs and handheld computers that are directly connected to the control system allow users to control processes while remaining fully mobile. Radio transmission modules are no longer the only devices that can be integrated into automation systems, as automation devices with built-in radio communication systems are now also available. Despite these developments, the leading fieldbuses still possess certain advantages that will ensure they remain in use for the foreseeable future in applications where time and security are critical.

Connecting the management level

Increased demand for the comprehensive availability of data from the field all the way to the management level eventually caused a veritable ethernet hype. Since then, the spread of industrial PCs and the ethernet has been accompanied by a rapid process of vertical integration which brings together systems and functions that were previously located on different levels of automation. As a result of vertical integration, managers receive the PLC production data at the planning level. Manufacturing execution systems (MES) serve as the link between the machine controls and the enterprise resource planning (ERP) system. In combination with the appropriate evaluation methods, this data link allows processes to be continuously enhanced, thus ensuring the production of safe, high-quality food products.

Anuga FoodTec (Cologne, 4-7 April 2006) will showcase the wide field of state-of-the-art data networking with a special focus on the food manufacturing industry.

For further information visit www.anugafoodtec.de