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That's what we call "nose-over", since it's pretty much guaranteed that your rocket is pointing
downward. There's also a low-velocity check, your rocket has to be going relatively slowly
before the deployment channels are enabled. For most flights that will be a second or two
before apogee.
In general, if you're using dual-deployment then you should set this to ZERO. The other settings
are designed for delaying the drogue using the Proton as a backup deployment controller in a
dual-controller redundant setup, or for special-purpose uses (i.e. the 5-second setting is designed
for ejecting ARLISS CanSats... if you're not familiar with them, check out www.arliss.org, it's
very cool). Typically, the backup controller will have the drogue setting delayed slightly from
the primary controller, so that if the primary controller fails the backup will fire and deploy the
drogue. You should model your flight with a program such as OpenRocket or Rocsim in order to
determine the best delay setting, you want to make sure that the rocket won't be going too fast
before the backup controller deploys the drogue. Typically, 1.0 to 3.0 seconds is adequate.
The fields are:
Delay (0-9 secs, default is 0):
Set the time delay from nose-over to deployment.
Deploy Mode (Igniter/Servo, default is Igniter):
Selects Igniter mode (on-off) or servo mode (CH1-3 only).
Pulse Width (Igniter mode only): (1-9 secs, default is 1):
Controls how long the output will fire in Igniter mode.
Servo Skew (Servo mode only): (CCW 100%-CW100%, CH1-3 only, def. is 100% CCW):
Controls how far the servo will move when triggered. When the servo is Reset, it will go in the
opposite direction the same amount, i.e. if you have it set to CCW 75% it will go to CW 75%
when reset.
About Servo Mode...
Servo mode assumes that the servo is going rotate to the selected position relative to the zero-
degree center position when actuated, and it's going to rotate in the opposite position by the
same amount when reset. Typically, you're going to use some kind of trap-door or pull-pin
mechanism, and there needs to be some way to close the door or reset the pin before you fly.
That's done with the Test Menu... more on that in the Appendixes.
The servo pulses are sent for 2 seconds, which is plenty long enough for any servo. Once the
two seconds are up, no more servo pulses are sent, so the servo basically stays where it is, at the
end of its selected travel.
Direction/Skews are in relation to the center point of the servo's travel. Ideally, a servo would
have 180 degrees of travel, so full counter-clockwise (CCW) would go 90 degrees to the left of
center, and full clockwise (CW) would go 90 degrees to the right of center. The reality is that
many servos do not have 180 degrees of travel, so we label them by percent of travel which is
ALWAYS related directly to the standard pulse-width of the servos (1.0 to 2.0 ms in a 20 ms
window).
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