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2.2.7 Theory of Operation
Background Information: AGLAS uses power line carrier technology to communicate between controlling units on an airfield
lighting series circuit. A AGLAS system typically consists of one high voltage modem, or Master, connected with the Constant
Current Regulator (CCR) powering the airfield lighting circuit and many slave units, or Remotes, collocated with individual lights in
the field. A typical AGLAS topology is provided in Figure 6.
Figure 6:
Typical AGLAS Topology
2.2.7.1 Architecture
Figure 7 depicts the general nature of the system components and their interactions. The “Control System”, shown in grey, is an
external ALCMS system that provides controlling commands and digests Master and Fixture status reports. There is typically only
one control system in the architecture. The “Master”, shown in blue, is the high voltage modem that communicates commands to
and receives status from the fixtures. There can be many masters in a given system. Masters digest commands from the control
system and provide status to it. Masters also communicate amongst themselves to maintain communication timing
synchronization. Each master communicates with the fixtures on its respective circuit.
Legend
Commands from ATC (Fiber Optic)
Field communication (Ethernet)
Power line
Dual
Remote
