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Industrial ETHERNET Switches ensure high reliability in a redundant ring


Industrial ETHERNET Switches from WAGO guarantee process safety through redundant ring topology in system networks. The contact technology specialist implemented this type of solution in the central compressed air supply for the BMW plant in Regensburg. The scalability of the network infrastructure, interoperability with third-party controllers, and V-LAN capabilities ensure that the system will have a long future.

Compressed air is an essential medium in automotive manufacturing. The BMW plant in Regensburg requires around 15,500 standard cubic meters of compressed air per hour – to handle chassis parts using vacuum grippers, for assembly tasks using compressed air impact screwdrivers, or to atomize paints in the Paint Shop. The dry, de-oiled compressed air for the entire plant is generated in the central compressed air supply in Building 91.1. It is located along the central line of the plant, along which all central function areas are grouped. The neighboring building, number 90.0, houses the central energy supply. The control room installed there scrupulously monitors the process for generating compressed air.

System with Vital Functions

Two years ago, the combined heat and power plant in the central energy supply was updated. Within the context of this project, a new, redundant network infrastructure with high failure safety was to be created for the adjacent central compressed air supply. In order to ensure redundancy for the infrastructure components, BMW decided on an ETHERNET ring topology. Instead of a hub distribution technology, the more flexible and safe switching technology was given a chance. The two buildings are now linked via fiber optic cables. In the central compressed air supply, the controllers and compressors are connected to the switches using copper wire.

The Regensburg plant had already had good experiences with WAGO’s automation products in previous years. This is why management decided to use industrial switches made in Minden for their ring. The scalability of the network infrastructure also played a role in this decision. This offered investment security by allowing the network technology to grow as new demands are placed on it. Due to the interoperability of WAGO products, the various third-party controllers in the network can be reliably coupled using the switches.

Managed Switch Ensures Safety

An important requirement for the system is that, during disruptions and failures, such as short interruptions, the system must autonomously restart and switch into safe operating mode. A configurable 852-104 Industrial Managed Switch functions as “Manager” for the ring’s necessary safety. Additional unmanaged 852-103 ETHERNET Switches are connected for distribution within the ring. If the managed switch detects a cable break or a fault in the network, it divides the ring into two lines so that all components are still available, except the faulty one.

Redundant Power Supply

The doubled, independent power supply also contributes to process safety. The WAGO Switches have ports for both power supply and redundant power supply, and can be supplied from different voltage sources/network devices. The switches also have two ports for dry contact that can be parameterized to acknowledge alarm functions using DIP switches. The dry contact is directed by a PLC to evaluate error messages.

The redundant power supply has a broad supply voltage range, from 9 to 48 volts, to ensure stable communication, even during short interruptions like voltage drops. The network components communicate with the zenOn control system from COPA_DATA using the TCP/IP network protocol. Due to the managed switch’s SNMP capability (Simple Network Management Protocol), the entire status of the network can be easily monitored via remote. Diagnostic data can be read from the controllers or even directly from the switches, thanks to a special SNMP driver in the control technology software. The 852-104 Managed Switch is designed for virtual networks (V-LAN’s) like those that are used in parts of the Regensburg facility. Should a V-LAN be used in the future in the central compressed air supply, the WAGO switch can be immediately used for the new application.

Good Support is Important

The technical aspects only formed part of the basis for the decision made by management at BMW Regensburg. Good support was also important for them. Robert Eisenhut, who is responsible for energy and building operations for Buildings 90.0 and 91.1, explains, “A direct contact person is important to us, because they can offer quick and targeted solutions. WAGO provides the customer care that is essential to our needs. We are well provided for the future in the central compressed air supply.”

Text: Jürgen Pfeifer, WAGO
Photo: Uwe Moosburger/vor-ort-foto.de