Airfield Lighting
Safegate Group
Manual
Date: October 2016
Ref: SL-RE-E_SL-RT-E_SL-RN-E_SL-RTN-E_SL-SB-E
Version: 1.4
Page 27 of 42
3.
OPERATION
In this section you can find a description of the different technologies that enable the
operation of the light fixture and instructions regarding programming and connection
of the light fixture. Before you start, make sure you have read and understand §1.1
Safety Instructions.
3.1
TECHNOLOGY DESCRIPTION
3.1.1
ASP Safecontrol System Technology
A Safegate ASP-SC system is designed to provide individual monitoring of airfield
lighting using the series circuit as a means of communicating status information from
airfield lights and sensors. The same concept is used for lighting control providing the
foundation for SMGCS or A-SMGCS, which includes for example automation of stop
bars with or without sensors, taxiway guidance (routing) in combination with status
monitoring. For more information, see ASP-SafeControl documentation.
3.1.2
SafeLED IQ and the 2A concept
The ASP-SC System, using the IQ concept, is designed to provide selective switching
and/or monitoring of airfield lighting by use of an addressable switching unit inside
each individually controlled light fixture. A SafeLED IQ light fixture is connected to the
secondary side of a standard series circuit isolation transformer. Communications
to/from a SafeLED IQ light fixture uses a unique power line communication technique
developed by Safegate Group where the communication signals are superimposed on
the series circuit current.
In a 2A system the CCR is set at a low constant current and the ASP-SafeControl
manages the intensity level of every single SafeLED IQ light fixture. Furthermore the
SafeLED IQ light fixture could have different light intensity levels in the same circuit.
3.1.3
Sensor Interface Unit (SIU)
Sensors for presence- and direction detection of aircraft and vehicles on the airfield
can easily be interfaced to the ASP-SC system using a SIU. The SIU communicates
the detect/no-detect status signals as well as its own status to the series circuit in the
same manner as the SafeLED IQ. The SIU is also connected to the secondary side of
a standard isolation transformer using a standard 2-pin FAA-style connector.
Connection to the sensor is established using an IP68 rated 7-pin connector. The SIU
can also supply the sensor with DC-voltage from a built-in current to voltage
converter.
3.1.4
Network Concentrator Unit (NCU)
The NCU concentrates all incoming status information from the field, both lamp and
sensor statuses. The NCU includes redundant capability.
3.1.5
Series Circuit Modem (SCM)
The SCM is an interface to the series circuit which receives command from an NCU.
The SCM connects to the series circuit via a standard isolation transformer and to an
NCU via standard RS485 or RS232 serial communication.
3.1.6
Series Circuit Filter (SCF)
The SCF is connected across the Constant Current Regulator (CCR) series circuit
output and is used to contain the communication signalling within the airfield circuit
and minimize feedback into the regulator.
