The timer event is most commonly used for complex staged configurations. As such the Timer programming on the Marsa33 is very flexible.
There are 2 Timer configurations on the Marsa33. These are "Timer" and "Timer-Mtr". Both function almost identically but the "Timer-Mtr" (timer motor) has slightly different safety oriented differences. These will be discussed at the end of this section.
The Timer can be configured to 3 different modes. These are:
1. Delay from Launch detect.
2. Delay from Motor burnout.
3. Fire on altitude during ascent (Altitude Up).
For mode 2, firmware build only supports timing from the first motor burnout detected. A future firmware release is planned to enable timer events on up to 3 detected motor burnouts.
Mode 3 allows you to program an event when the rocket reaches a given altitude during ascent.
The Timer-Mtr event is meant to be selected when that timer is used to start a motor. In this case extra safety precautions are enforced on the programmed event. These are:
1. Continuity check is disabled on a Timer-Mtr channel to keep that pyro outputs OFF until the rocket is in flight.
2. The Timer-Mtr event will not fire if an in-flight anomaly is detected.
Altitude at Time lockout
For Timer modes delay from Launch and Delay from motor burnout a altitude lockout can be set to inhibit a timer event if the rocket has not reached a determined altitude when the timer delay is reached.
This is accomplished by setting the lockout altitude in Mode 3 (Altitude Up) and returning to Mode 1 or 2 to complete the timer programming.
If you are using Mode 1 or Mode 2 and do not want an altitude lockout, be sure to go to Mode 3 and set the altitude to 0 or other very low altitude.