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The World’s Fifth Longest Tunnel Deploys Ethernet for Mission-Critical Traffic Control System
2012-08-27

Location / Country : Taiwan

Product Solutions:
EDS-505A/EDS-508A Series

5 and 8-port managed Ethernet switches

NPort 5210/NPort 5230/NPort 5232 Series

2-port RS-232/422/485 serial device servers


Introduction
Project Introduction

Taiwan’s Hsuehshan Tunnel is the second longest road tunnel in Southeast Asia (fifth longest in the world) and is composed of three independent tunnels (one pilot tunnel, one West-bound tunnel, and one East-bound tunnel) stretching 12.9 kilometers through Hsuehshan Mountain, the second highest mountain in East Asia.

Emergencies occurring inside a tunnel of this length can be disastrous, especially a fire-related incident. To minimize traveler casualties during an emergency, a traffic control system, consisting of two entry gates and two exit gates, is deployed to respond accordingly in events of emergencies by lowering appropriate gates to effectively divert traffic and prevent vehicle entry into dangerous areas.


System Requirements

• Industrial-grade durability to withstand roadside conditions
• Integration of serial-based PLCs to the Ethernet network
• Redundant network connectivity to ensure system functionality


Moxa Solution

The tunnel gate system is controlled by OMRON PLCs that respond to automated traffic control signals or can be manually operated. The serial-based PLCs are integrated onto the Ethernet network using Moxa’s NPort 5230 serial-to-Ethernet device servers. When an emergency occurs, the NPort 5230 allows PLCs to be directly accessible from the network to lower entry gates immediately.

For transmission requirements between the control gates, the system integrator utilized Moxa’s EDS-508-SS-SC to form a single-mode fiber optic Ethernet redundant ring network to ensure continuous network connectivity in case of a segment failure. The fiber ring network is also linked to the local control room via a fiber connection. With deployment of this reliable network for traffic control, Hsuehshan Tunnel operators can regulate traffic flow to ensure the safety of travelers in the event of an emergency.


Why Moxa

• The NPort 5230 device servers connect RS-232/422/485 serial devices for remote control/monitoring
• Easy configuration and real-time administration by web browser, Windows utility, or Telnet/serial console
• The EDS-508A-SS-SC features Turbo Ring and Turbo Chain technologies for recovery times under 20 ms at 250-switch load
• The EDS-508A-SS-SC supports IGMP snooping and tagged VLAN for more efficient bandwidth usage
• Moxa’s industrial products offer wide-temperature operation for severe environments
• All Moxa products are ruggedly designed for extreme and hazardous environments with high MTBF and a 5-year warranty