Moxa equips world's fifth longest tunnel

Moxa has fitted its Ethernet network equipment to the emergency traffic control system on Taiwan’s Hsuehshan Tunnel; the fifth longest tunnel in the world. The project is composed of three independent 12.9km (8 miles) tunnels, which run through Hsuehshan Mountain. 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 in the event of an emergency by lowering appropriate gates to effectively divert traffic and prevent vehicle entry into danger areas.

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 the entry gates immediately. For transmission requirements between the control gates, the system integrator has used Moxa’s EDS-508-SS-SC to form a single-mode fiber optic Ethernet redundant ring network, which will 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.

The company’s products are ruggedly designed for extreme and hazardous environments, with a wide-temperature range to withstand roadside or tunnel conditions. The NPort 5230 device servers connect RS-232/422/485 serial devices for remote control/monitoring and feature: easy configuration and real-time administration by web browser, Windows utility, or Telnet/serial console. The EDS-508A-SS-SC units feature: Turbo Ring and Turbo Chain technologies for recovery times under 20 ms at 250-switch load; and support IGMP snooping and tag VLAN for more efficient bandwidth usage.

31 August 2012