©2015 adb group. all rights reserved airfield. our field. led approach sequence flashing system...

Airfield. Our Field.

2015 ADB Group. All Rights Reserved Scope of Application The SFL800D serves as approach sequential flashing light system and runway threshold identification flash lights (RTILS) on airports. The SFL system enables the pilot already to recognize the runway from a long distance and marks the active landing direction. The threshold identification lights indicate the begin of the runway. The system supports two different flash frequencies (1 / s or 2 / s). 3 intensity steps allow the adaptation to the actual metrological view.

2015 ADB Group. All Rights Reserved System Design The sequence flash system is installed complementary to the existing approach center line The common length is 900 m with a distance of 30 m between the flash lights The two Threshold Identification Lights (TIL) are placed beside the green threshold lighting. To avoid short distance glare to the pilot the last 300 m segment in front of the threshold is often not equipped with flash lights. This is especially the case in CAT II & III systems.

Differences in electrical characteristics CharacteristicsXenonLED Sensitivity to moistureProtections requiredVery robust Work safetyHigh voltage issues (max. 15,000 V) Absolutely safe ( max. 70 VDC) Lifetime~ 500 to 10,000 hours. High voltage circuitry requires maintenance attention. > 25,000 hours Light head dimensionsSmall (with separate Individual Control Cabinet) Requires larger optical output Inset lights availableVery limited. Inset light conditions (moisture, condensation, vibration) not beneficial for high voltage Xenon. Yes, no restrictions. Max. intensity may be limited by the available optical aperture. Can be solved by twin light combination.

2015 ADB Group. All Rights Reserved Light output from Xenon and LED Xenon Flash is extremely short with a high intensity peak (t < 10 s [micro seconds]) According to the Blondel & Rey calculation, parts of the rising and falling edges do not contribute to the effective intensity (optical losses) LED Flash intensity shape is close to a rectangular flat light signal ( t ~ 50 ms [milli-secs]) According to the Blondel & Rey calculation, the total light output contributes to the effective intensity

2015 ADB Group. All Rights Reserved Lets remember the BrocaSulzer-Effect Broca and Sulzer published in ~ 1902 that short pulses of definitely visible light of a certain duration will appear brighter than if the pulses lasted longer in time. It seems that the effect is a result of the visual signal evaluation in the human optic nerve and/or brain (till now no valid explanation available). The Broca-Sulzer-Effect has been confirmed by several scientific studies. The effect does not increase the physical amount of light but improves the perception! Broca-Sulzer brightness enhancement occurs at stimulus onset for high intensity incremental targets. Here flash brightness is plotted as a function of duration for flashes of different luminances. Data from Hart (1987) et al.

2015 ADB Group. All Rights Reserved What will be the optimized flash duration? According the Broca-Sulzer-Effect a flash with a duration of 40 70 ms should appear VERY much higher than a longer or shorter flash.

2015 ADB Group. All Rights Reserved Selection of the Flash Duration The best solution is a 50 ms flash It provides the best perception according the Broca- Sulzer-Effect. The LED current / thermal peak and the thermal dissipation can be handled. The required capacity voltage to provide the flash energy in the 50 ms time can be kept in the SELV range.

What is the benefit of overlapping light pulses? Short distance view The eye resolution can separate all sequenced flashing lights Recognized is the intensity of an individual light e.g. 15,000 cd Long Distance view The eye resolution cannot separate individual lights Recognized is a virtual light with an intensity formed by all lights covering the smallest viewing angle. (e.g. with 3 adjacent lights = 45,000cd) Single Flash at the Threshold Flash Cluster in the Row

2015 ADB Group. All Rights Reserved Components Control Unit with the power and communication interface to the field components Power Distribution Unit to feed the single flash light heads with SELV power and communication The flash lights (elevated or 12 inset) with the high power LEDs and the control electronics. Note: the inset lights may be installed by pairs The sequence flash system consist of:

2015 ADB Group. All Rights Reserved Principle Cabling The Control Unit placed in a sub-station supplies the flash system via a single power cable. The communication between the Control Unit and the flashes is achieved on separate wires of the same power cable. Control Unit Overvoltage Protection Unit System Layout Inset lights may be installed by pairs to increase the photometric performances

2015 ADB Group. All Rights Reserved Power and communication to the lights Power Supply to the flashing lights 400 V / 50 Hz or 60 Hz power supply voltage on two wires of the supply cable. The Power Distribution Unit transforms that voltage down to 36 VAC supply voltage for the flash lights. The safe separation with the extra low voltage level provides a Safety Extra Low Voltage (SELV) with the highest work safety. Data communication to the flashing lights Control and monitoring by two other wires of the supply cable. The control unit sets the required intensity level and the system configuration of the entire system. Individual address of the flash head defines the time of ignition. After ignition each flash light sends automatically the actual status to the control unit. A pair of combined inset lights consists of a master and a slave unit. The function is defined by the internal configuration. Only the master communicates with the control unit.

E.g. for elevated light with breakable coupling Safety Extra Low Voltage (SELV) < 50V 400 VAC Principle Wiring Diagram and Voltage Levels Control Unit Overvoltage Protection Unit Cable joint Power Distribution Unit Cable joint Connector of the light 2 wires for power (400V) 2 wires for control and monitoring 2 wires for power (400V) 2 wires for control and monitoring HO7RN-F 4-core cable (e.g. for electrical frangibility on approach masts) Optional connector ( = separation transformer) (contractor- made)

2015 ADB Group. All Rights Reserved Control Unit Input: 400 V 3 phases Output: 4-core cable 2 wires for power (400 VAC), 2 wires for communication Interface to remote Control and Monitoring System (CMS) via parallel or serial interface. Local control for the basic functions. Detailed maintenance and configuration of the system can be done over an external maintenance computer with the optional service software lucDMC.

2015 ADB Group. All Rights Reserved Local Control and Monitoring Local control for maintenance purposes on the internal control module 5 push buttons to select function (TIL, SFL, flash frequency...) + 1 rotary switch for brightness and remote/local control 9 LED indications show the actual status of the system. Note: The use of the internal local control should be limited to trained electricians. With opened Control Unit the suitable safety regulations must be applied!

2015 ADB Group. All Rights Reserved Remote Control Interfaces Parallel (multiwire) interface with in- and outputs on 24 VDC level. 2 redundant CAN-Bus ports For an optional serial interfacing with any other CMS brand the following interface can be provided on request: RS-485 (EIA-485) MODBUS/RTU, RCOM, RCOMplus ETHERNET MODBUS/TCP PROFIBUS DP

2015 ADB Group. All Rights Reserved Flashing lights which photometric requirements? Flashing lights are not specified in ICAO Annex 14 or ADM However, it seems logical that the beam dimensions should be the same as steady burning lights. But what about the intensity? Average intensity of 20,000 cd is often excessive and produces glare. FAA limits the intensity to a maximum of 20,000 cd, with a minimum of 8,000 cd for elevated lights and 5,000 cd for inset lights. Many lights of this type installed worldwide. Ideal solution: Use the ICAO beam angles Average intensity for elevated lights: 10,000 cd to avoid glare (meaning peak intensity 15,000 cd as most FAA lights) Inset lights should be approx. 60% of elevated lights as per FAA, as they are seen at shortest distance.

2015 ADB Group. All Rights Reserved Flashing lights Elevated flash light The elevated type is available as as a standard light with 12,500 cd * nominal intensity. or a extra high intensity light with 20,000 cd * for best far distance operation under low vis. Choosing the standard light helps to increase the LED lifetime. 12 inset flash light The single inset light provides a nominal intensity of 6500 cd *. To increase the operational effective intensity, two synchronized insets next to each other can be combined to form a single point of light. * Typical values of the effective Intensity on the highest brightness step.

2015 ADB Group. All Rights Reserved Customer benefits Reduced maintenance thanks to the reliability and long life time of the LEDs (xenon flash tubes have a very short life) IP68 for all outdoor equipment, including the elevated lights This is extremely useful for approach lights installed on masts, outside the airport perimeter, above fields, roads or sea...

2015 ADB Group. All Rights Reserved Customer benefits Low power consumption: 20VA per light Inexpensive and easy installation: Standard low voltage cable (HO7RN-F), of small diameter; typically: 2,5 mm from the Control Unit to the first light then 1,5 mm to the end of the line Same 4-core cable used for both the power supply and the communication. No separate bus. No individual electronic cabinet: only a simple transformer that can be installed in a transformer pit Safety: SELV at the level of the lights, instead of 400 or 2000V.

2015 ADB Group. All Rights Reserved LED Flashing Lights First LED Approach Flasher has been operating in Kassel, Germany since April 2013. Further installations are in Muenster (Germany) Nordholz (mil) (Germany) Frankfurt (Germany) Geilenkirchen (mil) (Germany) Finkenwerder (Germany) Dubai (UAE) Iasi (Romania) Innsbruck (Austria) Warsaw (Poland) Many more are due to be in operation soon.

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