At its Emden plant, the VW Group has set up one of its biggest body shop and conveyor systems networked using INTERBUS for the production of the new Passat. VW has invested DM 436 million, DM 319 million of which was spent on the most modern production technologies in the body shop alone.
180 S5 DCB host controller boards, 550 robots, 120 000 interlinked digital I/O signals and
15 000 meters of laid optic fiber cable - these are the impressive controller reference data for INTERBUS in the body shop.
Good experience with Golf and Polo production in Wolfsburg was the reason why networking of the INTERBUS with optic fibers was specified throughout the body shop.
Welding robots, handling and adhesive applicator robots from Kuka of Augsburg dominate the body shop. The robot controllers as a slave and the decentralized peripherals are connected to the corresponding S5 controllers within the body shop cells by means of INTERBUS via optic fiber cables.
Optic fibers are essential
in the body shop thanks to
their immunity to electromagnetic influences
The optic fiber cable is resistant to oil and abrasion. It is a duplex polymer fiber cable designed for fixed routing and is well suited to applications in harsh industrial environments such as now represented by the body shop for the all-galvanized Passat shell. A distance of 50 meters can be bridged using the polymer fiber as the transmission medium. This is sufficient for 90% of all transmission links.
For EMC reasons, polymer fibers have also been used in the
6 200 meter long skid conveyor system supplied by Eisenmann GmbH of Böblingen and the plant constructor, IPS GmbH of Schöningen.
Technical Advantages in Optic Fiber Networking
Comparing the installation costs of an INTERBUS network using optic fibers and the costs for a standard system on the basis of copper cables reveals that the former alternative is 10-15% more expensive. The extra costs are because the transmitter and receiver modules are slightly more expensive and there is also the price of the duplex polymer fiber cables to consider. However, these extra costs are offset by technical benefits such as a straightforward optic fiber connection which does not need special tools or technical expertise to prepare. It is significantly easier and six times as quick to connect the optic fiber connector as a copper cable alternative.
Simple preparation of the
optic fiber connection without
needing special tools:
the transition from copper
to light by Optosub
Also, there is no more time-consuming troubleshooting in case of dry joints or short-circuits due to unspliced or faulty wires. Furthermore, they offer the benefit of resistance to electromagnetic influences. All of these points have led to only INTERBUS components with an optic fiber interface being used in the body shop.
Components which do not yet have an optic fiber interface are connected to the INTERBUS via converters or bus terminal blocks which undertake the transition from optic fiber to copper. The necessary specifications, circuits and component descriptions are available to all equipment manufacturers who intend to develop their own optic fiber-capable components for INTERBUS. The information takes the form of the guidelines for the INTERBUS Club and a supplement to DIN 19258. This ensures components from different manufacturers will work together in an INTERBUS network without
difficulty.
Dipl.-Ing. Reinhard Böhling