”GREEN” LIGHT IN THE VOLKSWAGEN PLANT

“It started when the former lighting controller became increasingly susceptible to faults after more than 26 years of operation and the eff ort for maintenance and material procurement increased signifi - cantly,” remembers Dieter Basse of AutoVision GmbH, who works closely with Volkswagen’s Emden plant on technical questions. Added to this, was the fact that effi ciency evaluations for the lighting used in the more than 15 plant halls was no longer possible. And thus a crucial question remained unanswered in Emden: how and where can valuable energy be saved? “This is not just a matter of the money,” emphasizes Werner Lindenbeck, who is responsible for operating materials management at Volkwagen’s northernmost production location in Germany: “We are very conscious of our responsibility with respect to the environment.”

Visions at the plant
One thing was already clear to the people responsible for the plant in Emden during the search for an alternative solution: they did not simply want to replace and thus tread water. Rather, they wanted to take several steps in the direction of the future. A cooperation arose in which the Emden plant, the plant service of AutoVision GmbH and Volkswagen Coaching GmbH (a 100% subsidiary of Volkswagen AG), worked together in interdisciplinary fashion. The goal: a Web-based lighting controller that every authorized employee can access via the intranet. It will be user-friendly and operated using graphic elements, which provides wide-ranging evaluation possibilities, and builds on the existing cabling of the old lighting system.  “To accomplish all of this, we were dependent not only on the latest programming and markup languages from IT, but also on systemindependent hardware components. This is where WAGO’s design clearly exceeded those of the competition,” says Dr. Steff en Wolf of Volkswagen Coaching, who was in charge of the development and implementation of the software. The crucial WAGO components are the programmable fieldbus controller (fl exible automation) and the three-phase power measurement modules (detailed measurement of energy consumption).

Control and monitor right from the office
One of the biggest challenges in designing the new lighting controller was the existing lighting network, which would remain in service. Earlier, the twisted pair network transmitted information from the switch cabinets in the heating plant to the individual relays in the halls. In order to shift the administration from the heating plant to the offi ce, the existing line network had to be expanded. “Here there was no choice but to add new CAT lines from the server room to the halls. WAGO’s ETHERNET controller was connected to these; it controlled the additional substations. This way, there arose a vertical integration of the data, reaching from the relays to the existing twisted-pair cabling to the intranet,” explains Dieter Basse. To handle this, about 14 master stations with ETHERNET controllers communicate via switches with the control system and via RS-485 bus module with a total of 220 substations with MODBUS controllers. The substations are also autonomous small controllers, which with 16 digital inputs and outputs control more than 7000 relays and thus all lighting elements in the plant’s halls. If the fi eldbus fails, then the substations are programmed to switch the lighting on immediately.

Measuring measurement
The new lighting controller is connected to the plant’s two weather stations. Together with the lighting scenarios saved for various work shifts models, the light in the halls is used very effi ciently. In order to obtain clear usage fi gures, the current for all three phases is measured using current transformers and the WAGO power measurement modules. From the PCs in the offi ces, it is possible to trace in detail which hall used how much current when. This creates an ideal basis for further optimization. Werner Lindenbeck looks back at the balance optimistically after just the fi rst few months: “We estimate that based on the new energy effi ciency, we will achieve six-digit savings.”