ESC Calibration

Automatic ESC calibration (all at once)

This method works once you have all the ESCs connected to the power distribution board and have connected all your RC cables as instructed earlier in the manual and have otherwise set up your multicopter.

Safety First! - Remove the props!

1. Disconnect USB and battery. The entire system must not have power
2. Turn your radio on and put the radio throttle stick at maximum.
3. Connect the Lipo to power the APM, radio receiver and ESCs. You will probably hear one or two short musical tone from the ESCs.
4. When the APM boots, the Red-Blue LEDs will cycle slowly and continuously
5. Leaving the throttle stick at full, disconnect the Lipo and reconnect it again to reboot the APM and power the system. The APM will now pass the radio signal directly to the ESCs, triggering calibration. The Red-Blue LEDs will cycle quickly - You will probably hear the short musical note and then 2 beeps (it depends on what brand of ESC you have; the 3DR ones will do as described). After the two beeps there is a pause, during this pause drop the throttle to full down. You should hear confirmation/arming beeps. Move quickly to the next step.
6. Do not unplug, move the throttle up a little to confirm all ESCs are armed and the motors are working in sync.
7. Unplug the battery again and then reconnect. Now arm the APM with right rudder/low throttle for 4 secs, release rudder and then all your motors should spin if given a little throttle.
8. Your ESC's are now calibrated. No further action is required.

Note: If after performing an Automatic ESC calibration the ESCs still beep quickly and continuously on power-up, make sure you have done the radio calibration in the Mission Planner!

Reference: ​https://code.google.com/p/arducopter/wiki/AC2_ESC