ESC Calibration

Apparently, on the PnF model ... the ESCs are not calibrated at factory. This might be because a radio is not installed until owner receives it. I figure, better safe than sorry ... so I researched it.

http://copter.ardupilot.com/wiki/initial-setup/esc-motor/#All_at_once_calibration

Just a reminder that the steps in this blog are presented in the proper chronological order. For instance ... the radio system (and other sensors) should already be properly calibrated in MissionPlanner before attempting this. Likewise, parameters like THR_MAX,1000 should already be set. However, PC should not be connected for this procedure.

Procedure seems to work, but the tones and led flashing are a little different than the posted "all at once" YouTube video (I think since he had full-APM Flight-Controller). If you look closely behind the Red Arming-Light Lens on the Nova, you will see there is actually 2 tiny leds behind it (a red one, and a yellow one). When they both flash (I call it a strobe effect) it indicates you have entered a calibration-mode ... one that you initiated with TX and quad (as opposed to one from MissionPlanner). In this case it's the ESC (All-at-Once) Calibration Mode,

http://www.youtube.com/watch?v=gYoknRObfOg

Also, he is using Mode-1 radio, while most of us here in the USA are flying Mode-2 (throttle on left). As the video shows, you enter this mode by holding the (Mode-2) Throttle (left stick) down and to the right ... like you are Arming, but much longer.

Nova ESC Calibration Summary (with FrSky radio set):

1. Start with Nova's props removed and lipo battery disconnected.
2. Turn on TX and move throttle to Full.
3. Switch to Stabilize Mode on TX.
4. Connect Nova main lipo battery
5. Red/yellow leds behind Arming lens will strobe-flash
6. Unplug Nova lipo, wait 3 secs, then plug back in (leave TX Throttle on Full)
7. Nova's red/yellow leds behind Arming lens should still be strobe-flashing
8. Fairly quickly (within 1.5 secs) move Throttle stick to OFF (or bottom of throw)
9. Nova will beep 3 times (2 short, 1 long) signally this step is complete (with v1.0 ESCs)
1. With v1.6 ESCs, you might get an extra 4 beeps in the beginning, but not with v1.0 ESC IIRC.
10. You should now test throttle and get an even response from all 4 motors.
11. Unplug main lipo battery, wait a few seconds, and then reconnect it.
12. Now arm the motors (with right rudder/low throttle for 4 secs). 
13. All your motors should spin if given a little throttle.
14. Your ESC's are now calibrated. No further action is required.

I can't think of a good reason to have motors spin on arming (and several good reasons NOT to), so I then went to:
MissionPlanner / Config & Tuning / Standard Parameters / ...
and set the parameter "MOT_SPIN_ARMED" to "Do Not Spin".
The parameter had a null or empty value at first. Strangely, I had to set it and write it several times before it took effect. Anyway, it works properly now (even after power on/off cycle). A related parameter is THR_MIN, but I left it unmodified.

Motor Test is not required for successful ESC calibration, but it certainly would not hurt to do it. They should all spin and sound about the same. I test motors from MissionPlanner/Terminal (type "test", then "motors"). It will start at Motor#1 [M1] (aka Fore-Starboard Motor) but instead of following the true X4 diagonal-like M# pattern, it will instead ... proceed Clockwise around quad (so it's M1, M4, M2, M3).

When I power up my Nova with LiPo battery, mine always plays (a kinda musical) series of tones or beeps ... short-short-short-(pause)-long. This is with four stock v1.0 ESCs and the 3S-LiPo.
Stock-white Radio Note 1: I don't have one (or have ever held one), but according to forum posts, the ESC calibration with "stock white radio set" is a little different due to the way the TX & RX Bind together on power-cycle. Some say to use a temporary 5v power source (likely a battery) to keep on-board RX powered-up during entire procedure. Or, you can try this way-1 (direct-link) or this way-2 . Finally, Mr.Jagger in forums says this version #3 is best. Be sure to find one that actually works and "settings take".

Stock-white Radio Note 2: True APM Modes and comparable (Nova-CX20 Mode): Stabilize (Manual), Loiter (Stable), Simple (Direction Locked), Altitude Hold (Altitude Hold), RTL (Return To Home). In my docs, I always use the true APM flight-mode-names.

Stock-white Radio Note 3 (using confusing Mode-names from Nova/CX20 Owner's Manual): If you are having trouble Arming quad, here is a summary: If you have GPS-3D Lock (solid green light) AND hdop <= 2.0, you can (and should) Arm in Stable switch mode. Then, switch to Manual mode and take-off. Otherwise, you can just Arm in Manual mode ... but don't expect RTH (pilot invoked or emergency) to work during that flight. Also, don't switch to and try to use any GPS dependent modes like Stable during that flight.