Post-Katrina: Rugged fiber-optic network is set to report through hurricanes
|Weed Instrument EOTec 2000 Industrial Ethernet Switched Media Converters and Switches provide fiber optic conversion to and from wire based Ethernet for long distance communications over multi-mode or single mode fiber optic cable.|
For levee and canal monitoring in post-Katrina New Orleans, U.S. Army Corps of Engineers installed a new monitoring system with help from Prime Controls, Sutron Corp., and Weed Instrument fiber-optic based communication modules. Good engineering and the latest technology is helping keep New Orleans dry. The
The devastation that resulted from Hurricane Katrina prompted the Corps, which has responsibility over the city’s system of levees and canals, to install a new monitoring system on the 17th Street, Orleans Avenue and London Avenue canals. For that general contractor Prime Controls turned to real-time hydrological and weather monitoring system developer Sutron Corp . of Sterling, VA. Sutron Weed Instrument fiber optic based communication modules.
|Weed Instrument fiber optic topologies include repeater, point-to-point, daisy chain, star, self healing ring and dual self healing ring.|
“The goal of this project was to monitor meteorological parameters. They wanted to monitor if a storm was coming through,” says Faisal Al-Mtwali, an electrical engineer with Sutron. “They also were monitoring the water level in the canals.”
Such information is vital if the operation of a canal’s pumps and gates are to be automatically managed by a supervisory control and data acquisition (SCADA) system. The control system needs data quickly, which is one reason why fiber optic communications were selected.
Another reason has to do with the far-flung nature of the operation. There are 12 stations in the project, scattered along tens of thousands of feet of canals. The runs are too long for any copper wire but well within the capabilities of a fiber connection.
|Sutron Monitor Datalogger is said to be a easy-to-use, affordable (&$1000) weather or hydro station logger with 16 measurements and equation processing.|
Another critical selection criterion was low electrical power draw on the Weed modules. This becomes vitally important when the system goes into battery back up mode. If a hurricane were to hit and knock out region-wide power, having a low power draw would be an advantage. The system can
The system has operated since December 2006. Before that, there was no automatic way to bring
Since a great portion of New Orleans is below the water level of nearby Lake Pontchartrain, this lack of visibility increased the city’s
|Sutron Satlink2 Transmitter/Logger (SL2) has|
As part of the infrastructure improvements implemented after Hurricane Katrina, the Corps installed monitoring stations. Since these had to work no matter the conditions, they have redundant communications capabilities. The primary telemetry path for the SCADA system was over fiber optic cable running Modbus industrial automation protocol.
Products from Weed Instrument play a key role in this communication. “We use the 2C10, the electrical module interface, for the RS-232/RS-485 protocol,” says Al-Mtwali
The connection between SCADA, pumps, and remote gates has to be robust to
Another data telemetry conduit is through the GOES satellite, running a high data rate option to a geostationary satellite thousands of miles overhead. This path provides hourly transmission of 15-minute interval stage data of such measurements as water level, temperature, relative humidity, rainfall, and barometric pressure, as well as wind speed and direction.
The GOES link provides wide-area dissemination of the water level data, with the information transmitted to and monitored by personnel at the Corps’ Vicksburg, MS, regional headquarters. This connection is extremely reliable, requiring no land lines or terrestrial repeaters.
It also can automatically sound an alert if a problem is detected, explains Al-Mtwali.
The final data route is through Iridium satellite phone modems, a slower and more costly link than GOES. One advantage that the Iridium channel offers is two-way voice and data communication, which can be important in a crisis. Iridium also offers a last ditch link, used if all else fails.
Because of the multiple channel setup, if the fiber breaks the station will still be logging and transmitting data. Indeed, so long as there is power and the antennas exist, the monitoring stations can continue to do their job. This information then helps the Corps do its job in ensuring that the levees and canals protecting New Orleans don’t fail.
To date, the system has not been subjected to a severe test;
The Corp offers a video with details on the Hurricane and Storm Damage Risk Reduction System .
The Corp also offers more information, photos and maps of the New Orleans canals and levees .
— Edited by Mark T. Hoske , editor in chief
Control Engineering News Desk
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