FF1TERM and FF2TERM zero after calibration?

[Trnquill]

I just changed motors and propellers of my hex to lower kv and bigger diameter. I updated ESC32 firmware to latest official version (http://autoquad.org/software-downloads/?did=78) and ran the calibration as usual with qGroundControl v1.3 RC1. I left ESC32 to its default settings before calibrations.

After first calibration run (rpm to voltage) FF1TERM and FF2TERM said both "NaN". Not a number? I found it odd but couldn't remember if this was the case with my previous calibration runs with the previous motors and props, too.

After second calibration run (current limiter) FF1TERM and FF2TERM said both "0". I started comparing them to old calibration files and found out they had always had some value before. Why not now?

I noticed after upgrading firmware of all the ESC32's that I had forgot to adjust the motor poles count from default 14 to 28 that is actually is. So, I have to run the calibration again. But is there some explanation or a reason why FF1 and FF2TERMs were left 0 after the calibrations?

I'll report back if they are still 0 after second attempt.

[LPR]

I found that having the apms set too high during calibration will cause the "nan" to appear.

Larry

[Trnquill]

[chschmid]

Exactly. Put that to whatever your Motor (and prop) is rated.

If you do not have the numbers, connect the esc to your Radio and read the amps draw with a A-meter. Use this.
Cheers
Christof

[Trnquill]

Yeah, thanks! I know that field. I started gently with 10A (just to see if something explodes... ) but can't remember if the FF terms were NaN after that RpmToVoltage run. I then bumped it up to 30A or 35A (my motors are rated at 36A) and did both calibration runs, which resulted in FF terms being NaN and then 0.

I'll try today with lower max current.

[chschmid]

Maybe you can measure the max Amp of your mot/prop Combo or calculate it. www.ecalc.ch Use this value.

Cheers
Christof

[Trnquill]

eCalc gives maximum current of 20A, I'll use that.

[Trnquill]

25A didn't help, still NaN. But using 20A as max current did the trick! Thanks!

I think this is something worth mentioning in the wiki AND qGroundControl UI tooltips.

[chschmid]

Good to hear that it worked out well for you.

Cheers
Christof

[proff]

hi all
sorry but I experiencing the same problem with or without the High Amps limit my motors ( ony-22 740Kv ) are limited to 18A.
I tried with 5 to 20 A (5 8 10 12 15 16 18 20 ) always same problem always "nan" values (no 0) I got one time
FF1TERM 0
FF2TERM -1.90299e-31
but as FF1 is 0 results when commanding are the same
I'm calibrating with 4s lipo and 9x5 graupner eprop propeller
does any one have an idea ??

I tried to put some other values calibrated befor for totaly differents motor and props (tmotor 4008-12 800KV with graupner eprop 13x8)
FF1TERM +8.86648e-08
FF2TERM +1.83983e-03
and it works commands are accepted but result in RPM closed loop are not the good one ( obviously )

thank's for your help