Airports present a dynamic environment, with runway and taxiway expansions and surface rehabilitation ongoing. Airside construction and maintenance are common events, whether for new construction or maintenance. With fiber optic cable runs all around, there exists the risk that the fiber can be damaged during construction and the control system will be knocked offline.
As industrial wireless solutions began to emerge, Liberty considered their distinct advantages in use as backup communications to the fiber lines. Cost reduction associated with installation, maintenance, and replacement of fiber was a major driver, but even more valuable was the assurance of increasing uptime by implementing an independent backup communication system.
“Uptime and maintenance aspects are a huge consideration,” says Liberty’s control systems product manager Tom Wodzinski. “If the system goes down, a maintenance team must be brought in. The costs of this can be significant, particularly if the occurrence is at night or on a weekend. But, if the system is able to automatically switch over to the wireless backup, this cost is avoided.”
Liberty has been using Wireless Ethernet products successfully since the late 1990s, however it began to experience problems as the amount of multicast I/O traffic on their network increased. After some research and consultation with the automation group at Gerrie Electric Distribution, Liberty discovered that ProSoft Technology’s 2.4 GHz Industrial Hotspots were better able to support their application needs.
Comments Rob Porter, automation product manager for Gerrie, “When ProSoft Technology released these radios, which were specifically designed and optimized for EtherNet/IP, it made for the right solution and Liberty was quick to take advantage of it.”
“We went with ProSoft because they are able to handle high multicast traffic,” says Wodzinski, “ ... and upon using the radios we also found the configuration tools were much more simplified. From our standpoint as a system integrator, we were able to reduce development and installation costs because we could employ the same local electrical contractors that perform the installation of our electrical equipment to mount the data radios.”
Seamless Transition to Backup Communication
In one installation, Liberty supplied the airfield lighting control system to the Canadian Forces Base (CFB) in Trenton, Ontario. CFB Trenton is a military airfield providing deployment support for military and humanitarian efforts around the world. The basic system relies on wireless back up for the ALCMS functions. In a later system expansion, eight new Rockwell Automation POINT I/OTM drops were added to the wireless network, providing real-time control and monitoring of high mast apron lighting around the airfield. The cost to install seven wireless nodes to the network came in at less than half of the cost of a conventional hardwired configuration.
In June 2010, the unexpected did happen. A contractor dug through a major telecommunications duct bank containing the main fiber optic communication cables for the airfield lighting. Communications and airport operations continued flawlessly on the wireless radio network for the next week while new cables were procured and installed.
Reaching Remote Sites
In a majority of airside projects, site equipment is deployed over a large physical area. Locations may involve a few I/O points and remote operator consoles which are potentially distributed over distances up to five miles. In these situations, it’s often not economical to run fiber and wireless becomes the primary line of communication.
In fact, Liberty has standardized on wireless as the primary network for the more distributed applications on the airfield, including control from central deicing facilities. Because of the toxicity of the anti-freezing agent glycol which is used in the deicing process, environmental regulations now require airports to designate an area for the de-icing process, where glycol used to spray the planes is collected into reservoirs, cleaned and discharged. These deicing facilities are generally remote from the main terminals, so independent lighting systems may be used to guide planes into the appropriate bays for spraying.
Mobile Connectivity and Transferability
INFORMATION TECHNOLOGY 2004 In this special section, AIRPORT BUSINESS takes a look at information technology products and services available to airports and airport-based businesses. More...