What is the AGL control architecture?
Four levels of control — tower, ALCMS, substation and CCR — with commands passing down, status coming back up, and local control as the fallback.
The AGL control architecture arranges control of the airfield lighting in levels. A request made at the tower is coordinated by the ALCMS, carried out by the substation controller and delivered by the CCR to the series circuit. Each level passes the command on and reports back what happened.
Two ideas make the arrangement safe to use. Priority: a level set to local typically takes precedence over remote commands, so staff working at a substation or CCR are not surprised by a remote command. Resilience: redundant servers and network paths, and field controllers that keep running without the centre, mean losing one part does not lose the lights. Local or manual mode is a control fallback, not isolation. The circuit still has to be isolated, locked out and proved dead before work.
- Tower. The operator selects the lighting needed from a touch screen.
- ALCMS. Checks the request against logic and interlocks, and records it.
- Substation. The PLC or local panel passes the command on only if the selector allows it.
- CCR. Sets the circuit current and brightness step.
- Feedback. Status, faults and alarms return up the chain to the screens.
- Fallback. If control from above is lost, the substation or CCR can be operated locally.
Levels of control inside the ALCMS: who commands, which level has priority, how resilience and local control are arranged.
The chain of layers from operator to lights. See AGL control-system architecture.
Frequently Asked Questions
Q1What is the AGL control architecture?
The way airfield lighting control is arranged in levels, from the tower down to the CCR at the field end. A command is passed from level to level to switch a circuit or set its brightness, and status and alarms come back up the same chain.
Q2What are the levels of control?
Typically the tower or operator position, the ALCMS server and screens, the substation controller (a PLC or local panel), and the CCR itself with its local or manual front panel. The exact levels and names vary by airport and are set by the project specification.
Q3Which level has priority when commands conflict?
In most designs the level closest to the equipment takes priority when it is set to local, so a remote command cannot operate a circuit that staff are working on. The rules differ by site and system, so check the project specification and the manufacturer's documents.
Q4Is local mode a substitute for isolation?
No. Local mode only stops remote commands from operating the equipment. Before working on a circuit it still has to be isolated, locked out and proved dead under the permit-to-work.
Q5What keeps the lights operable if part of the control system fails?
Designs commonly add redundant servers and network paths, and field controllers that keep running without the central system. A local or manual mode at the substation and CCR lets staff operate the lights if control from above is lost. How much is provided depends on the project.
Q6How is this different from the AGL control-system architecture entry?
That entry in the Airfield Layout division shows the chain of layers from operator to lights. This entry focuses on the levels of control within the ALCMS division: who can command, which level takes priority, and how resilience and local control are arranged.
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