Desired operation of a new sequencer.
Hello,
I'm finishing the development of a new sequencer/failsafe for air operated retracts, but have a doubt about what is the desired operation after power-up,so I would like to have some feedback of "real life" use.
The device is composed of two sections. One is an air pressure sensor used for to detect an air loss and to extend the gear before running out of air. The current pressure can be transmitted over telemetry to Jeti, Multiplex and Futaba radios. Failsafe pressure can be adjusted from 0 to 10 bar.
The other section is the sequencer. It have 5 outputs (4 if telemetry used) and one input. The outputs can drive air valves or servos, for servo use the endpoints of the 5 outputs are freely adjustable. The sequencer have 5 steps (Gear Up, GearDown and 3 intermediate steps). In each of the 5 steps, the position of the 5 outputs is configurable, as it is the time spend on each step. All programming is done by use the Xicoy data terminal (used in Wren, KT, Jetcentral, JetsMunt and other engines).
All is working fine, software is in last test phase and hardware being manufactured. We plan to launch the product in a couple of weeks, but still I'm not sure ofthe power-up sequence, meaning what the device should do after power up.
In current software,once the power is applied, the device wait 3 seconds to give time to the receiver output to stabilize. After this delay, if the command received is "Gear Up", it does nothing to prevent the gear to collapse if the gear switch on the TX has been inadvertently left in gear up position. Once the command received is "Gear Down", it arms, sets the outputs to "gear down" position and on next transition to "Gear Up" it does the retract sequence as programmed.
This should work fine if the gear is always extended at power-up, that is the usual situation, but in the case that the system is switched-on when the gear is retracted, it looks that could cause issues. If a door is programmed to be in closed position when the gear is down, then this door will keep closed when the system set the outputs to "gear down" position once armed, so this will prevent the strut to extend and possibly causing damage to the door.
To prevent this possibility of damage, I think that a solution could be that at power-up the system set the all the outputs to the doors to OPEN position, allowing the gear to extend if it was retracted, and few seconds later, the doors that should be closed when the gear is extended, will close. This avoid the possibility of door damage, but will cause the doors to cycle at each power-up. Only the doors that should be closed when the gear is down would cycle.
Would this be acceptable? I'm open to suggestions, now it's the time of the "wish list".
Thanks for your feedback,
Gaspar
Last edited by Gaspar; 11-15-2015 at 02:55 AM.