HobbyKing 300MM HEX Seems to go to 100% throttle on Fail Safe
« on: September 03, 2017, 10:20:31 am »
Like my title says I was trying to do a range check and suddenly my motors went wide open when I expected them to come to a stop.  I have tried resetting fail safe in the LibrePilot GCS and on the Tx to both extremes, but the behavior is always the same about 1 full sec of 100% throttle then nothing.  I took a screen shot of the GCS you can see as soon as I turn off the Tx my throttle setting jumps to 1900+.  Is this in my flight controller / my Tx / or my Rx any help would be appreciated.

Attached is Screen shot as soon as the Tx is turned off and a GCS export.  Below is a video I made showing the Tx and GCS settings and my hex losing its shit when the Rx turns off.




• HobbyKing 300 Hex
• Orange R618XL Rx / Devo 7E Tx
• KINGKONG 1806-2280KV Motors
• KINGKONG 12A 2-4S OPTO BLHeli ESC’s
• Mini CC3D Flight Controller
• 5040 Propellers

Re: HobbyKing 300MM HEX Seems to go to 100% throttle on Fail Safe
« Reply #1 on: September 03, 2017, 10:50:33 am »
I see that you are using PPM.  I recall seeing a similar issue with OpLink PPM a few months ago.

This may be that PPM stream remains valid for a short time at the beginning of failsafe, and with long pulses instead of short ones or "last valid".

You might try reversing your transmitter throttle channel in the transmitter, and also in the GCS Input section.  That way it should go low instead of going high.  This still isn't perfectly correct in that you should be able to set the failsafe throttle to 50% and have it go there from where ever it was rather than first jumping to 0% or 100%.

Someone who knows this issue better will probably be along to clarify some of this.

f5soh

  • *****
  • 4007
    • LibrePilot
Re: HobbyKing 300MM HEX Seems to go to 100% throttle on Fail Safe
« Reply #2 on: September 03, 2017, 12:10:20 pm »
If FC failsafe occurs the Throttle value you setup will be applied.
You can check the FC failsafe status looking at the SystemHealth panel, the orange INPUT alarm says the FC is in failsafe.
At same time the Input tab show slider to their max, but not used.

In your case seems the full Throttle comes from your receiver that still output a valid signal for a short time.

From receiver manual:
Quote
SMART FAILSAFE FEATURE
The R618 X features advanced failsafe. Advanced FailSafe is ideal for most types of aircraft. With advanced FailSafe, when signal is lost for the short time (less than 1 second) all channels will hold last command. If the signal loss occurs for more than 1 second all channels go to predefined position according to transmitters sticks and switches` positions remembered during binding procedure. That is why it is important to set a throttle channel at zero and other channels (switches and sticks) to your preferable hold position during binding procedure.

Try rebinding your receiver and take care about stick positions.

Redo the Transmitter wizard or a calibration, your neutral for Throttle is not correct.
« Last Edit: September 03, 2017, 12:14:07 pm by f5soh »

Re: HobbyKing 300MM HEX Seems to go to 100% throttle on Fail Safe
« Reply #3 on: September 10, 2017, 06:39:43 am »
I did end up reversing the the throttle and reversing throttle in GCS.  The throttle neutral is set to 1500 in GCS and that is accurate 1500 is midstick on my Tx.  And like the picture shows as soon as my Tx is turned off the value shoots to 1934  I don't see how that relates to neutral.   Additionally my Tx has been recently calibrated and works fine with my other quadcopters.  This is the only machine that behave this way.

Re: HobbyKing 300MM HEX Seems to go to 100% throttle on Fail Safe
« Reply #4 on: September 10, 2017, 08:59:18 am »
Throttle neutral should be set so that the motors are spinning slowly but reliably; not 50% power.

The default has FC failsafe (not RC failsafe) setting the motors to min (to turn them off), not neutral.  If your min is 1900 it will set it to 1900.


I am told that this was the GCS input tab, not the output tab.  The above is for the output tab.
« Last Edit: September 10, 2017, 06:18:08 pm by TheOtherCliff »

f5soh

  • *****
  • 4007
    • LibrePilot
Re: HobbyKing 300MM HEX Seems to go to 100% throttle on Fail Safe
« Reply #5 on: September 10, 2017, 11:21:55 am »
Quote
Throttle neutral should be set so that the motors are spinning slowly but reliably; not 50% power.
Throttle neutral in Input tab has nothing related about the Motor neutral in Output tab

Quote
The throttle neutral is set to 1500 in GCS and that is accurate 1500 is midstick on my Tx
Your wrong Throttle neutral simply mean while moving the Throttle stick you start to really apply Throttle at middle stick.
If you want to use the half stick range instead of full stick travel, you're fine.

As already reported your 1934µs value comes certainly from recorded failsafe values while you do the last binding.

Redo the binding with all sticks in neutral position and Throttle stick to minimum, move all trims to 0 and undo the reverse throttle you set.
Redo transmitter wizard (and set the Throttle neutral to 1500 if you really want that) because you have others issues in channels values.
« Last Edit: September 10, 2017, 11:25:12 am by f5soh »