DESIGNING AN AIRFIELD LIGHTS CONTROLLER (Second try)
Howdy Guys,
I need some advice in designing and building a circuit that will sequentially turn on three lights and after a preset time, sequentially turn them back off. The lights are part of an airfield lighting system on a private residential airport. I originally posted this request on AAC about half a year ago ( https://forum.allaboutcircuits.com/...ling-the-lights-at-a-private-airfield.148305/ ) but that thread languished and ultimately died, largely because I was unsure of what I wanted to accomplish at the time. While that thread attracted several helpful replies, I've decided to start a new thread to keep the old discussion from creeping in and confusing things! Please note that since our runway is restricted (not open to regular public-use) the FAA doesn't approve or disapprove such installations other than to offer guidance.
The purpose of the three light systems are to aid an inbound pilot in locating our runway at night and determining the wind direction and intensity prior to landing. The lights will be turned on by the inbound pilot keying his/her communications microphone 5 times within 5 seconds on a designated frequency (an FAA standard). After landing, the pilot can extinguish the lights by clicking his/her mic another 3 times, or the lights will automatically extinguish after 12-15 minutes. A professionally-built ground-based receiver/decoder for receiving the pilot’s mic clicks (aka “squelch breaks”) has already been purchased but I still need to build the light sequencer and timer.
The sequencer/timer that I need to build should function as follows:
1. Upon receiving and decoding the pilot’s mic clicks, an internal set of “dry” SPDT contacts will change state for 1, 15, 30 or 60 minutes (selectable during system installation) and will immediately activate our rotating beacon.
2. 2-5 seconds later (the actual delay will be determined after initial system installation and testing) the windsock’s floodlight will illuminate, thus completing the “turn on” sequence.
3a. The “automatic shutdown” sequence will start 10-15 minutes later (again, determined by system testing). The windsock’s floodlight extinguishes first and the rotating beacon will extinguish 2-5 seconds later. At the same time the beacon extinguishes, the obstacle lights on top of the tower will illuminate and remain illuminated for 5 minutes.
- or -
3b. The system can be shut down manually by the pilot by clicking his/her mic 3 more times after the turn on sequence has completed. (This will toggle a different set of SPDT contacts within the receiver/decoder unit.) Other than shutting down earlier than the automatic sequence (3a) the manual shutdown sequence will be the same order as the automatic sequence.
Notes:
1. All lights and the rotating beacon will be activated via heavy duty relays, lighting contactors. or solid state relays located at the top of the 42ft rotating beacon tower.
2. The Receiver-Decoder unit, as well as all other beacon controls, will be located in a hangar 150ft away. All tower power circuits are 110VAC and the control circuits are 24VAC. Twenty 16ga "signal" wires and five 12ga "low voltage power" wires in underground conduits connect the control unit in the hangar to the relay cabinet at the top of the beacon tower
3. All of my designs so far have been based around commercially-available "delay" relays because a “simple” sequencer is preferred over one that requires complicated programming. That said, I’m not totally against a “Smart Relay” or Arduino, providing that I don’t have to call NASA for help in troubleshooting the system!
Unfortunately, all of my designs so far have turned out amazingly way-overcomplicated! (A simple circuit somehow eludes me!!!) Your help is greatly appreciated!
Harvey
Howdy Guys,
I need some advice in designing and building a circuit that will sequentially turn on three lights and after a preset time, sequentially turn them back off. The lights are part of an airfield lighting system on a private residential airport. I originally posted this request on AAC about half a year ago ( https://forum.allaboutcircuits.com/...ling-the-lights-at-a-private-airfield.148305/ ) but that thread languished and ultimately died, largely because I was unsure of what I wanted to accomplish at the time. While that thread attracted several helpful replies, I've decided to start a new thread to keep the old discussion from creeping in and confusing things! Please note that since our runway is restricted (not open to regular public-use) the FAA doesn't approve or disapprove such installations other than to offer guidance.
The purpose of the three light systems are to aid an inbound pilot in locating our runway at night and determining the wind direction and intensity prior to landing. The lights will be turned on by the inbound pilot keying his/her communications microphone 5 times within 5 seconds on a designated frequency (an FAA standard). After landing, the pilot can extinguish the lights by clicking his/her mic another 3 times, or the lights will automatically extinguish after 12-15 minutes. A professionally-built ground-based receiver/decoder for receiving the pilot’s mic clicks (aka “squelch breaks”) has already been purchased but I still need to build the light sequencer and timer.
The sequencer/timer that I need to build should function as follows:
1. Upon receiving and decoding the pilot’s mic clicks, an internal set of “dry” SPDT contacts will change state for 1, 15, 30 or 60 minutes (selectable during system installation) and will immediately activate our rotating beacon.
2. 2-5 seconds later (the actual delay will be determined after initial system installation and testing) the windsock’s floodlight will illuminate, thus completing the “turn on” sequence.
3a. The “automatic shutdown” sequence will start 10-15 minutes later (again, determined by system testing). The windsock’s floodlight extinguishes first and the rotating beacon will extinguish 2-5 seconds later. At the same time the beacon extinguishes, the obstacle lights on top of the tower will illuminate and remain illuminated for 5 minutes.
- or -
3b. The system can be shut down manually by the pilot by clicking his/her mic 3 more times after the turn on sequence has completed. (This will toggle a different set of SPDT contacts within the receiver/decoder unit.) Other than shutting down earlier than the automatic sequence (3a) the manual shutdown sequence will be the same order as the automatic sequence.
Notes:
1. All lights and the rotating beacon will be activated via heavy duty relays, lighting contactors. or solid state relays located at the top of the 42ft rotating beacon tower.
2. The Receiver-Decoder unit, as well as all other beacon controls, will be located in a hangar 150ft away. All tower power circuits are 110VAC and the control circuits are 24VAC. Twenty 16ga "signal" wires and five 12ga "low voltage power" wires in underground conduits connect the control unit in the hangar to the relay cabinet at the top of the beacon tower
3. All of my designs so far have been based around commercially-available "delay" relays because a “simple” sequencer is preferred over one that requires complicated programming. That said, I’m not totally against a “Smart Relay” or Arduino, providing that I don’t have to call NASA for help in troubleshooting the system!
Unfortunately, all of my designs so far have turned out amazingly way-overcomplicated! (A simple circuit somehow eludes me!!!) Your help is greatly appreciated!
Harvey
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