esc calibration problem cc3d nighthawk libre/Openpilot

[jar]

I am at the stage where i am running through the configuration for my cc3d on LibrePilot (same thing happens in the last OP release)

When I get to ESC Calibration it will not calibrate correctly - I get a couple of short beeps then a long flat tone. running the rest of the procedure will NOT get the motors spinning at neutral speed or get any other tones from the ESC';s (step 6 in the calibration procedure)

However, if I say PWM control not PPM, i do seem to get the right noises from the ESC, they can calibrate and I can do the neutral speed setup.

It is definitely set to ppm and of course if i leave it to pwm then the tx/rx setup does nothing (it does allow me to configure the TX/RX part of the setup if i set ppm)

I must have made a typical newbie error somewhere, does anyone have any advice?

Setup

• Nighthawk 250/2 kit with Simon series esc';s and MT2204 KV230 motors
• cc3d
• frsky d4r-II (bound to a djt module in a Turnigy 9xtreme running ERSky 9x)
• set to ppm mode using pins 1-2 and 8 on the ccd

Note - even if i save the results of my test back to the cc3d, when i start the test again it ALWAYS defaults to pwm, i thought it would have remembered this but as i haven';t used it before i don';t know.

[ched]

I thought cc3d used pin3 as the ppm input not pin8? Is there a reason you are using pin8?

[jar]

Thanks for that, but it has confused me now !

The configuration summary in librepilot shows it on pin 8 (as does a lot of other sites)

http://uavspeak.com/how-to/lumenier-qav250-build-part-3/ ( about halfway down)

Hopwever here shows pin 1-2-3
http://www.dronetrest.com/t/turnigy-9x-connecting-ppm-to-cc3d/1364

I must be missing something :-)

John

[ched]

The second link you posted might give you a clue
This seems to show that pin8 is fine if you are using oneshot.
It looks like you can only use pin8 for ppm if you are also using oneshot (esc setting).

So if your esc are oneshot and you have connected pin8 I guess you can select the option for pin8 in openpilot. Otherwise it might be worth using pin3 for the ppm signal. Just one thing, I remember on my cc3d the colour code was not the same as the diagrams. ie pin3 on the cc3d receiver plug was not the white wire!!!!! So check the pin numbers.

Hope that gives you some clues?

[quadfather]

You say Simon Series ESCs.  That suggests Emax 12A to me, so the following ESC-related advice is based on that.  They don';t support OneShot unless you have flashed BLHeli to them.

Remember, don';t mess with the quad on the bench and have the props on the motors!

I wouldn';t bother with the vehicle setup wizard.  I had better results doing the setup manually.

In the Hardware section select PPM+NoOneShot for the receiver port, the PPM signal is on pin 3.  If you indeed have OneShot ESCs, then select PPM_PIN8+OneShot and the PPM signal is on pin 8.

In the Vehicle section assign the motors to the output channels according to the image.  If for some reason your ESCs aren';t plugged into the FC in the default order you can change that under Motor Output Channels.

In the Output section set the update rates to 400 Hz.  I found that 490 Hz or PWMSync does not work reliably on these ESCs.  If you have OneShot then set that in the update rates.  You could try PWMSync, the receiver port needs to be in OneShot mode for this.

Remember to save every time you make changes in one of the tabs.  When you have set it all up as above disconnect (power off) the FC, wait a few seconds, then plug it back in.

Then proceed to the Input section and do the transmitter calibration.  Ideally the lowest value is 1000 or a little less, and the highest value is 2000 or a little more.  You can adjust this using weights or subtrims on the transmitter.  My Taranis with D4R-II goes from 990ish to 2010ish out of the box, which is a good range and I don';t bother fine tuning this (though some people would).  The crucial bit is that you can go from 1000 to 2000.

To manually calibrate the ESCs, disconnect the battery from the quad, but leave the USB cable plugged in.  Go to the Output tab and do the following:

1. Enable Live Testing

2. Link all for motors by ticking the boxes on the far right

3. Click on one of the motor sliders (so that the GUI has focus on them) and press End on your keyboard.  The sliders should all jump to the far right (2000).  Press Home on your keyboard and they should all jump to the left.  If that works reliably, press End so they are on the far right.  Don';t click anything else now to retain focus on the sliders.

4. Plug in the battery and wait for the calibration song.  On the default Emax firmware that';s just a low-high beep sequence.

5. Quickly press Home, the default firmware does not play a confirmation, but simply boots the ESCs with the ascending melody (one beep per battery cell).  If you wait too long the ESCs will enter programming mode, something you do not want (ask me how I know).  If you do accidentally enter programming mode (it plays a longish melody) don';t do anything with the sliders and disconnect the battery.

6. Manually move the sliders to the right until all motors spin.  If you can get them to start within 10us of each other, that would be a pretty good result for the Emax ESCs.  If the difference is bigger, you could repeat the calibration and see if it helps.

7. Untick the Link boxes and disable Live Testing.

8. Save

Let us know how you get on.

[jar]

Thanks for the replies guys, yes they are the emax supplied ones with the nighthawk kit. They are not the oneshot ones (althought the emax website itself lists oneshot esc';s as a no cost extra with the kit)

I think i got confused with the conflicting walkthroughs that show different configurations but do not always mention what components they use.

when i walked through the configurator, and chose the rapid esc ( not oneshot) with PPM the diagram shows me pin 8 it only shows pin3 with the standard esc';s so maybe thats not 100% correct :-)

Once all 3 sprogs are in bed I will have a go again with quadfathers rather comprehensive help in the above post 

John R

[ched]

Good Luck and let us know how you get on.

[quadfather]

Thanks for the replies guys, yes they are the emax supplied ones with the nighthawk kit. They are not the oneshot ones (althought the emax website itself lists oneshot esc';s as a no cost extra with the kit)

I think i got confused with the conflicting walkthroughs that show different configurations but do not always mention what components they use.

when i walked through the configurator, and chose the rapid esc ( not oneshot) with PPM the diagram shows me pin 8 it only shows pin3 with the standard esc';s so maybe thats not 100% correct :-)

Once all 3 sprogs are in bed I will have a go again with quadfathers rather comprehensive help in the above post 

John R

I believe that RapidESC uses the PWMSync update rate.  For that you need to configure the receiver port as OneShot (even though you';re not using OneShot), or the wizard probably does it for you.  If you go with standard PWM for the ESC you can set it up as in my post above, i.e. using pin 3 for PPM.

[jar]

Well thanks to the quadfathers walkthrough i managed to get as far as the motor test and it all seems to be working as expected, with one small issue.

Three of the motors spin up within 10us of each other (1087, 1077 and 1080) the other spins up at 1036. I will try to calibrate again when i get a chance to see if it helps. Thanks ever so much for the help!

John R