Important safety issue with Aurdupilot 2.7. I speak from experience. No damage done,
but it was a completely unexpected jump to full throttle while I was attempting to program my
Castle Phoenix 25 in a skyfun sitting on my workbench. To enter programing mode you must power up the ESC with the throttle set to max. The moter ESC won't arm unless it gets a zero signal. So I turn on the Tx at full throttle. Power up the AP/receiver, and after the servo demo RXXXXXXZZZZZZZZZZZZZZZZ
I quickly held it down with one hand and went for the fuse with the other. It sucked in the foam block it was sitting on
and stopped the prop just before I pulled the motor fuse. Unplanned 100% throttle is unsafe.
While the Tx was sending a control signal for manual the Demo_Servos called the <Set_servo_mux>.
This causes the main 328 processor to over ride the fail safe processor by over powering its pull up resister.
When your in "hardware manual" you can be overridden. I have known that for a while. Its OK to do for a short time.
When the set_servo_mux does it's over ride thing, the ESC gets it's zero thottle and arms.
After the servos wiggle and and a short delay, back to the receiver at 100%
I have taken out the demo servos for this reason.
Anticipation of something unforeseen like this is why I have a 15 amp motor fuse on the outside of the fuse.
It also serves as a safety switch so I can power up the computer without the ESC. I am not using the BEC in the ECC for
avionics power. That way if there is a meltdown of the motor or ESC or a crash blocking the prop
the fuse will blow to the ESC and everything else still works.
You need to be a member of diydrones to add comments!
Replies