Westermo Data Communications has received an order for sixty five of their Lynx400 ultra-rapid reconfiguration industrial Ethernet switches to support an industrial Ethernet network that will manage safety information on the new A75 motorway in France. The A75, also known as `La Méridienne’, is the panoramic motorway between Clermont-Ferrand and Béziers, which provides a new North to South route in the exceptionally beautiful region of the Massif Central made famous by the new Millau multi-span cable-stayed viaduct which it runs over.

In a forthcoming project, the networked safety information system including variable message signs (VMS), weather stations, vehicle counting, emergency calls and surveillance videos will all use an Ethernet network to send an receive all information.

The network architecture is based on a backbone consisting of two gigabit high-speed Ethernet trunks. Each node is configured for optimum transport of the information flows for the various functions. Westermo Lynx400 Ethernet switches with optical couplers cable of spanning over 40 km enable local communication with the VMS, radio data transmission station and weather station.

The flows generated are channelled by VLAN sub-networks to avoid network overloads and ensure real-time interchange of all the necessary information. The selection of Westermo industrial products with high MTBF and wide temperature, vibration and shock resistance ensures the high availability of this solution.

In addition to the Industrial Ethernet switches, Westermo are also supplying LD-64 converters specifically for the Millau multi-span cable-stayed viaduct. The variable message signs (VMS) located just before and on the viaduct itself communicate over a serial communication protocol using a redundant optical fibre Ethernet link based on Westermo LD-64 converters.

The Westermo LD-64 converters are used to build a redundant ring network over fibre where connected equipment has either an RS-232 or RS-422/485 interfaces. As the fibre is completely insensitive to external interference it is the perfect solution for applications in exposed locations such as the roadside and when there is a requirement for fault tolerant communication.

The LD-64 provides a high level of data security as fibre or fibre pair failure does not affect the communication. There are also digital alarm outputs that can be connected to a relay to control an external alarm indicator.

LD-64 supports data rates of up to 375 kbit/s, which meet the requirements of the Millau project. The device can also handle transmission ranges up to 25 km using single-mode cable essential in this case.

Lynx Switch

LD-64