[SOLVED] 3.5.0-rc4 disarms immediately without saying the reason

After I got the right firmware installed in [SOLVED] 3.5.0-rc4 Looses frame type on reboot and calibrated my sensors I could finally arm the copter (well, almost).

I press the safety switch, make sure that the motor interlock switch is in the right position and give the stick command for arming. I get the beep/armed light and GCS says ARMED except about a second later it disarms itself with no messages to the GCS. I can’t get the motors to spin during that second either.

Has anyone else encountered anything similar?

What do you have the disarm delay parameter set for?

At first it was set to the default value, I think maybe 2 seconds? EDIT: looking at the source the default might have been 10 as well

I tried setting it to 0 (=disabled) with no effect

It’s probably disarming for another reason. What mode are you in?

I’ve tested Stabilize and Acro modes. I’ve attached the logs from one attempt.

When those logs were taken the copter was powered and connected through USB with no power to the PM or motors.

I’ve also tried with power through the power module and no USB connected. The issue seems to be the same.logs_not_arming.zip (353.0 KB)

EDIT: There is also no GPS lock as this is indoors but that should not be an issue in Acro/Stablize right?

Looks like you have the motor interlock enabled. So to arm you’ll need to have the interlock so that the motors don’t spin. Then after arming you need to flick the switch so that they’re allowed to spin.

The vehicle is arming but then disarming about 5 seconds later. I think our motor interlock, when enabled, halves the regular disarm-delay time. If that seems odd, talk to Rob Lefebvre! The motor interlock was mostly added for helicopter users I think. Maybe you want to use the kill switch instead? It’s very similar but a little less complex. It’s explained on the wiki a bit on the “auxiliar function switches” page. http://ardupilot.org/copter/docs/channel-7-and-8-options.html

Yup, that was it. Thanks!

I didn’t realize that with the interlock you need to arm in one position then flick the switch to the other position. The documentation doesn’t really say that clearly.