Applications

Optimal advanced technology at BMW

Benefits from WAGO-I/O-SYSTEM
The advanced technology sets specific demands on the fieldbus connections. Large quantities of inputs and outputs are scattered kilometers apart in various small groups.

New configurations are created with each new change in production. The standard fieldbus node was never used to its fullest potential and therefore was too expensive for many application. The advanced technology at BMW, Munich reacted quickly to this. WAGO-I/O-SYSTEM is standard installation for the past two years, used mainly in raw material as a point control.

The BMW building "Vierzylinder" (four cylinder) is also a symbol of Munich. Since 1922 this has been home to the company's main office and production. The oldest producer of BMWs worldwide, the Munich branch is not only for management but also a production site. The plant near the Olympiapark is where the 3 series BMW is presently being built. The plant is being used at 100% capacity. More than 170,000 vehicles have passed through this plant -- from limousines to BMW compacts all having different options. New options are continuously added.

Because of its location, expanding the Munich site is impossible. All available rooms need to be used at their fullest capacity. This also applies to the raw material and the production departments that press each individual part of an automobile. Over 400 robots are used.

Network

Sometimes the various models run through one production stations and sometimes they run through different production stations. In addition, there are stations for random quality controls and eventually some re-working. The conveyor resemble more of a network than the classical seperate lines. This network is adjusted for the production of new models and any variations.
BMW uses an electronic hanging conveyor system from AFT GmbH (Schopfheim, Germany) for moving the crude car assemblies. This utilizes both signal and hoist joints. A ceiling rail carries the electronic transport device attached with different items such asparts or partially assemblies. Each moving device is equipped with its own electronic drive. Even fifteen kilometers of rail at different levels connected by a hoist joint can work well. The work stations are at ground level and the above tracks distribute and shunt the units.

The problem

Each line contains a write/read system that uses an antenna to communicate to the SPS. Switches and disconnectable channels make it possible to control the individual carriers. During a large remodeling project in 1996, this communication between the carriers and SPS was changed to fieldbus technology. Parts for production were already being delivered using an Interbus; this was also used for advanced technology. Introducing fieldbus technology into the advanced technology, gave the planner yet more specialized problems:

Though only binary signals are being processed, input and outputs are distributed extent routes. The pneumatic operated devices with one straight and one branched rail, have more than 200 switches and need 8 inputs and 2 outputs with 24 V control voltage. Depending on the routing track switched paths, empty carriersdetection, etc are needed. An input and output of 24 V to 230 V is needed. Standard fieldbus nodes with exact quantity of inputs and outputs and only one switching voltage, usually had unused modules or complex wiring.

Changes to these routes need be made efficiently. Engineer Michael Philipp, is responsible for the planning of advanced technology at BMWs raw material: "The limited space in the building needs be used optimally. Any remodelling cannot stop production." The remodelling of the routes will be done in small steps and during breaks. This created the need that the fieldbus node communicate with the switches. If a route change is imminent, the switch including the controller will need to be changed. The fieldbus and power supply can be reconnected. Any additional inputs and outputs needed for more switching positions should be easily installed. The search for a solution brought Mr. Philipp to the WAGO-I/O-SYSTEM. BMW has been using WAGO rail-mounted terminal blocks with CAGE CLAMP® already.

The solution

Due to the past success, this new system was accepted with open an open mind. Michael Philipp: "We already had determined to go with the cage clamp connections. WAGO made its offer." Within a short time frame, a test program was initiated.

The test phase

Compatibility with the existing controls was proven quickly. A test length of 4 weeks, also proved that the WAGO I/O System would have no problems. Nothing stood in the way of installing a prototype into the extisting device field. Only 3 months after the start of th test, BMW was convinced in the WAGO IO System. These were brought in on a large scale.
The implemention from 1996 to 1998 was uncomplicated. Since then the system has proven itself as absolutely realiable. The switch boxes are built perfectly around the nodes. The limited space left will still allow any expansions. Michael Philipp (pictured): "If a production change requires additional input or outputs, we just fit the new bus modules to the node." Even permanent sub-distribution is more compact thanks to WAGO front entry technology.

The finish

Besides the switch controls, BMW uses WAGO I/O System in the finishing of the front-end assembly, hood and trunk. Space is a concern even here and can become an issue for the planner. No space is available to stock parts next to the production lines with conveyors. Parallel to the lines is an endless chain of parts for each work station. The speed of the chain allows for assembly and removal without any stops. The shortest distance and an ergonomical height eases the work. Furthermore, compact and user-friendly tools and assembly devices are integrated into each station. Parts are taken off the rail that runs over the production line, and then attached to the automobile. As the line moves, the tool moves along on the rail.

Das Lob

Für einen reibungslosen Ablauf ist nicht nur eine leistungsfähige Steuerung gefragt, sondern auch eine intelligente und flexible Anbindung der Peripherie. Über den Bandlauf verteilt sind Meldeleuchten, Werkzeugabfragen und Fahrschalter. Werkzeugabfragen schützen die wertvollen Montagelehren vor Kollisionen. Fahrschalter dienen zum vorübergehenden Anhalten der Montagelinie.
Neue Modelle fordern neue Komponenten, andere entfallen dafür. Das wandlungsfähige WAGO-I/O-SYSTEM wächst nach Bedarf mit. Kontinuierlich wird Prozeßoptimierung betrieben. Statt "Hier hätten wir noch eine Meldeleuchte einbauen sollen" heißt es mit WAGO: "Hier muß noch eine Leuchte hin. Bauen wir sie ein." Statt endloser Verkabelung wird einfach eine weitere Klemme auf den Feldbusknoten aufgerastet.
Michael Philipp: "Mit WAGO können wir Feldbusknoten ohne Reserve aufbauen. Die Granularität ist für uns ein großer Kostenvorteil."
Immer noch werden alte Verkabelungen aus der Anlage entfernt. Dezentrale Automation macht sie flexibler und übersichtlicher - mit dem WAGO-I/O-SYSTEM konsequent bis in die Spitzen der Peripherie.