As general contractor
for AUDI AG in Ingolstadt, Dürr Systems GmbH, Stuttgart, completed
the new paint shop within under 1 1/2 years. The A3, A4 Limousine, A4 Avant
and the Audi TT are painted here. Audi und Dürr stepped on new ground
with their distributed control technology and their universal PC-based
visualization and control system.
Their job was to build a paint shop that should allow 400,000 bodies and
parts to be painted annually. The four individual, model-oriented segments
of the paint shop allow a high degree of flexibility with respect to segment-independent
operating methods, planning of capacities and capacity utilisation strategies.
When they enter the paint shop, the bodies are pre-sorted with the color
sorting memory and then transported to the corresponding segments according
to vehicle type. Parts made of aluminum, plastic or diecast are, for the
most part, painted in the same way as the bodies and then supplied "just-in-time"
to the 4 so-called "deco" lines for assembly.
High demands on the control technology
To control a paint process of the above functionality, flexibility
and complexity, the control system has to fulfil the following requirements:
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Highly flexible control functions;
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Simple grasp of the complex system due to easy operation and monitoring;
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Integration of the control system in Audi's vehicle transport control system;
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Networking the controllers and computers to form a complete system with
uniform information management;
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Over 90 % system availability
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Restart time less than max. 15 minutes after failures
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Reduction in the variety of spare parts by use of uniform control components;
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Reduction in engineering and commissioning costs
Control technology "Made by Dürr"
Control systems for process, application, material handling and environmental
technology have been structured uniformly and connected via a higher-level
control system. Great emphasis has been placed on compliance with industrial
standards such as Windows-NT, Ethernet, TCP/IP and INTERBUS.
Decentralisation of control technology
Dürr DIM 21 (Decentral Intelligent Module control system for the
21st century) replaces the central switch cabinet technology which is the
current state-of-the-art technology. Small control modules are located
directly on the spot on the mechanical functional units and are networked
via INTERBUS. At the Audi works in Ingolstadt, the first paint shop ever
was decentralized as a consequence using this technology. PHOENIX motor
control switches, for example, were used as DIM 21 modules for materials
handling technology to control the roller conveyors, transverse shifting
carriage or elevator tables, as well as self-built standard modules.
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66,000 digital I/Os, 7,400 analog I/Os and 2,000 motor control switches
were networked and connected to the PLCs via approx. 500 bus terminals.
110 gateway modules establish the connection of the various INTERBUS lines.
The I/O interfaces between the PLCs are thus effective, transparent, interference-resistant
and easy to configure.
The following advantages of decentralization using DIM 21 modules have
proved to be effective in practice:
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Saving switch cabinet space;
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Fast trouble-shooting by simply exchanging entire modules;
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Integration of extended diagnostics information via detailed fault messages;
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Lower level of electro-magnetic interference in the network compared to
"conventional switchgear" due to electronic switching via the motor control
switches;
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Reduction of building and installation costs.
Dürr Basis Software controls the painting process
The plant is controlled by 90 Simatic S5-115U controllers. These PLCs
communicate with the Dürr EMOS-PCs (Equipment Monitoring and Operating
System) used for visualization as well as with the entire Dürr EMOS-SM
control system via an Ethernet bus operating under TCP/IP. The 200 semigraphical
operating panels used are also connected to the PLCs via INTERBUS. The
advantages:
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Location and elimination of malfunctions during production without programming
equipment;
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Graphical or semigraphical depiction of the conveyor lines on the spot
on the operator panels allows the variables and markers to be displayed
convenientla for error analysis and elimination.
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On the spot parameterization of the frequency converter;
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Data exchange with the read/write system via INTERBUS without any additional
equipment being connected.
PC-based operation and monitoring
Operating, monitoring and parameterization of the entire painting process
was implemented and standardized entirely on a PC basis. The user interface
not only provides detailed and transparent information, but also guarantees
immediate reaction in the case of malfunctions in the sprawling sections
of the plant. 50 Dürr EMOS PCs were distributed to cover the paint
shop. Today, all areas of the process, i. e. process engineering, application
technology, materials handling and environmental technology are operated
using one uniform user interface.
Conclusion
Consistent use of modules and standardization, the use of tried and
tested standard components, and decentralization within the whole plant
made it possible to put such a complex plant into operation so quickly.
Using the technology successfully implemented in Ingolstadt, paint shops
– including another paint shop for Audi in the Brazilian Curitiba
and paint shops for VW in Shanghai and Bratislava – are being
built and put into operation for DaimlerChrysler in Juiz de Fora, Brazil,
and for Steyr Daimler Puch in Graz.  |
