There's hardly a more important topic at the filling station than the fuel price, irrespective of which side of the fuel pumps you may be standing on. Consumer and manufacturers of fuel and lubricants are pleased about every single cent that they can save.
Savings can be achieved by opting for a single system to handle wide-branching production facilities, a system that has already become a byword for economy. AS-Interface pricing was the decisive reason why an AS-Interface solution was selected along with PROFIBUS PA for the new building of a large-scale fuel and lubrication production system in the Rhine-Main area, completed at the end of 2006.
It's a well-known fact that this automation-based bus (AS-Interface) operates more cost effectively and efficiently than any other. The integration of a general AS-Interface network in the subordinate fieldbus is no more complicated than that required for a normal standard slave, so the user benefits from the inherent strengths of the AS-Interface, particularly in combination with other systems.
AS-Interface can be perfectly integrated into this extensive system with multiple sub-branches and large network coverage. A clear advantage is the fact that the AS-Interface does not need to consider the topology coupled with its ability to use unscreened cables. The fast connection technology helps to save additional time during commissioning. In the new process system, including storage technology for fuel and lubrication, a dual master device was used to achieve a network distance of roughly one kilometer.
The star-shaped wiring starts in the control cabinet with several repeaters and power extenders. The power supply with auxiliary power is provided by two 8 A power supply units in K24 housing. For emergencies, an extra 8 A power supply unit provides a backup. It can be activated when required. Additional repeaters in G4 housing were used in the field to bridge the distance. Quite often, there was a distance of 20 meters or more between stations. The AS-Interface capable position sensors are used to scan flaps and switch mechanical drives. This enables the AS-Interface to control the system's lifelines. Pepperl+Fuchs also has an AS-Interface module for Zone 1 that is fully enclosed and approved by the German Technical Inspection Agency TÜV. Cleverly grouped, significant savings can be achieved in the area of process engineering.
Because of the large network distances involved, the system is approved using the AS-Interface Analyzer, while telegram quality is also checked. This form of diagnosis enabled optimizations to be made using repeaters while the approval report also documented the functional integrity of the AS-Interface. After all, process reliability is what it is all about.