S800 Return to Home won't work.

S

steveq

Member
Hey Gurus!

I have a newly constructed DJI-S800. Put it together myself with no problems. It flies beautifully and is rock solid in the air, GPS lock is solid.
My radio is a Futaba 14SG. I have the Futaba Telemetry transmitter on board and a FatShark FPV transmitter.

Everything is working, IOC/Course Lock etc. EXCEPT "Return to Home".

I have mapped/assigned RTH to switch SF (a two position switch) and have set up the Failsafe. I'm pretty sure my switch set ups are correct, as all the others I have mapped/assigned have worked well, and the Wookong software changes correctly when I flick the RTH switch.
I have calibrated the compass and the LED changes accordingly when doing so. (Incidentally, do I need to do this before each flight, or is it a one off?)
When I flick the switch to return to home, nothing happens. It just sits there, almost as if it didn't even get the command (perhaps it didn't?).

I'm loathed to try a Failsafe (turning off the radio) until I know RTH is working properly, as if something goes wrong, recovery might not be an option!!

I've tried pretty much all I can think of, and I have scoured forums to try and find an answer.

Does anyone have any suggestions please?

Thanks heaps,

Steve Q. :)
 

EastCoastJib

EastCoastJib

Member
If I'm not mistaken this is a bug in the DJI firmware. the x3 return to home function is not working.... you have to mix in a separate 3 position switch or 2 position switch to throw your control mode in to fail safe. There are several threads that explain in great detail how to get this accomplished. Mine works beautifully with the mix, or if I turn the transmitter off... both conditions will return to home perfectly! I will try to find the specific thread and post it here.
 


P

PeterLester

Member
Nearly all issues will be with the RC transmitter configuration.....

Search for Jon Desjardins Futaba Transmitter and NAZA setup videos on Youtube using the Futaba T8FG Super and you should get most of the answers for your Futaba 14SG. I had similar problems but discovered that my trainer switch setup was intercepting the RTH function and disabling it......One has to be very thorough with NAZA or WKM Assistant bench testing before flying. Just because each function is verified thru to the MR does not mean that bench testing is complete. One has to input other switches to test for interference from other Tx switches etc. If your MR LEDs lights are responding to tell you RTH has been activated, then the RTH instruction has not been recognized by the controller.


steveq said:
Hey Gurus!

I have a newly constructed DJI-S800. Put it together myself with no problems. It flies beautifully and is rock solid in the air, GPS lock is solid.
My radio is a Futaba 14SG. I have the Futaba Telemetry transmitter on board and a FatShark FPV transmitter.

Everything is working, IOC/Course Lock etc. EXCEPT "Return to Home".

I have mapped/assigned RTH to switch SF (a two position switch) and have set up the Failsafe. I'm pretty sure my switch set ups are correct, as all the others I have mapped/assigned have worked well, and the Wookong software changes correctly when I flick the RTH switch.
I have calibrated the compass and the LED changes accordingly when doing so. (Incidentally, do I need to do this before each flight, or is it a one off?)
When I flick the switch to return to home, nothing happens. It just sits there, almost as if it didn't even get the command (perhaps it didn't?).

I'm loathed to try a Failsafe (turning off the radio) until I know RTH is working properly, as if something goes wrong, recovery might not be an option!!

I've tried pretty much all I can think of, and I have scoured forums to try and find an answer.

Does anyone have any suggestions please?

Thanks heaps,

Steve Q. :)
Click to expand...
 


EastCoastJib

EastCoastJib

Member
Also, you will need to recalibrate the compass if you change your flying field..(location), and addition or subtraction of weight/gear (center of gravity) or any changes to the gains for any changes to measurements related to the x,y,z axis of compass or IMU. Dont ask me how I know... :shame:
 

P

PeterLester

Member
EastCoatJib....... thx 4 the valuable tip...... couldn't understand why RTH did not work for me last night..... I had moved the IMU forward and down onto the antivibe mounting position and therefore had to change the x,y,z for IMU position. Seems to me though that a small change in flying field location should not require a magnetic compass recalibration since it is the angle of declination from true north that is the main concern and that is more of an East West longitude/distance issue.


EastCoastJib said:
Also, you will need to recalibrate the compass if you change your flying field..(location), and addition or subtraction of weight/gear (center of gravity) or any changes to the gains for any changes to measurements related to the x,y,z axis of compass or IMU. Dont ask me how I know... :shame:
Click to expand...
 

S

steveq

Member
Thanks heaps for your advice guys, it appears I now have something to do on Saturday!
I'll keep you posted on how it goes. :)
 

gtranquilla

gtranquilla

RadioActive
RTH tested again tonight after recalibrating the compass but it still did not work properly. After turning around and heading over the takeoff position it continued to climb........Had to override RTH to get it home safely.
EastCoastJib said:
Also, you will need to recalibrate the compass if you change your flying field..(location), and addition or subtraction of weight/gear (center of gravity) or any changes to the gains for any changes to measurements related to the x,y,z axis of compass or IMU. Dont ask me how I know... :shame:
Click to expand...
 
Last edited by a moderator:

EastCoastJib

EastCoastJib

Member
Did it record home position successfully upon powering up? When you start motors the first time you should see 10 or so fast cyan (light blue) flashes. This is of course with no red lights before starting motors for more than 8 seconds.
 

gtranquilla

gtranquilla

RadioActive
Yes.... waited for all red flashes to end...then took off in GPS mode with cyan leds flashing rapidly.... flew for a couple of minutes at a distance from takeoff position, activated RTH and it turned around, heading back over the original takeoff position but then began to climb.....and continued to a high altitude. It worked before many times... the change was the repositioning of the IMU from the center top of the MR to 18 cm forward and down to the antivibe platform..... Had to mount it backwards because the IMU cable is too short...... but configured WKM Assistant with all new x,y,z data. Then recalibrated the GPS compass as per manual......
EastCoastJib said:
Did it record home position successfully upon powering up? When you start motors the first time you should see 10 or so fast cyan (light blue) flashes. This is of course with no red lights before starting motors for more than 8 seconds.
Click to expand...
 

EastCoastJib

EastCoastJib

Member
Hmmm... just out of curiosity, what is the Tx failsafe throttle percentage set to? I've got mine set to 51% although I don't think that matters unless you actually turn off the Tx. Under the f/s tab in assistant.. are you set to alt-go home? what is the setting for height/altitude?
 

gtranquilla

gtranquilla

RadioActive
Thanks for your help...... I retraced all of my steps and made a very slight slight adjustment to COG then recalibrated the digital compass in a nearby abandoned soccer field away from vehicles etc. did a quick flight and tweaked the gains a bit in the air ..... but ran out of time for another RTH test...... will try later......... Throttle is configured above 10% as usual, Al-Gohome is configured on with height set at 25 meters.... Taking this item to a HPR - High Power Rocketry Launch event this weekend to get some aerial videos of some very big rockets on the pad and during launch. Will test RTH again at the site when conditions are right.
EastCoastJib said:
Hmmm... just out of curiosity, what is the Tx failsafe throttle percentage set to? I've got mine set to 51% although I don't think that matters unless you actually turn off the Tx. Under the f/s tab in assistant.. are you set to alt-go home? what is the setting for height/altitude?
Click to expand...
 

CrashMaster

CrashMaster

Member
Apparently firmware 5.22 has a flaw in it, now that will be new for DJI, where the manually engaged RTH will not work. However, I know low voltage RTH still works because it did that to me 2 days ago. Apparently it will be corrected in the next update.
 

S

steveq

Member
[Resolved] S800 Return to Home won't work.

Hey Guys,

Return To Home worked! Thanks so much for your help. For others trying to get this working here is a summary.


  1. (Apparently) there seems to be a bug in the Wookong software's return to home switch. You can still get it to work manually by setting up your failsafes on your radio. See the following YouTube videos on how to do this: http://www.youtube.com/watch?v=ck3tu-4UVgg and http://www.youtube.com/watch?v=SmDehc5PEUQ
  2. Calibrate the compass. This should only have to be done once at each new location. There is a video here for how to do this http://www.multirotorforums.com/showthread.php?11119-DJI-Naza-M-V2 or do this:
    1) Flick the man - atti. - atti./gps switch quickly back and forward 6-10 times.
    2) You should get a blue LED
    3) Hold s800 level/horizontal, rotate on the spot clockwise 360 degrees holding the multicopter
    4) You should get a green LED
    5) Turn the s800 on its side (90 degrees to horizontal) and rotate clockwise 360 degrees
    6) You should get a white LED - all done
    7) Red LED means it failed... try again.
  3. Upon powering up, wait for a bust of green flashes from the LED, then NO red. This means the Wookong has locked its current position as the home position. Can take up to 1 minute.
  4. Fly a distance greater than 10m from your recorded home position.
  5. Flick your RTH switch and watch her fly home and land autonomously!

Many thanks to EastCoastJib and PeterLester for their help.

Steve Q. :)
 

S

steveq

Member
Hey Again,

Am I safe to assume that this little trick of forcing a Failsafe to activate a Return to Home manually, means that I can now free up X3 to use on my gain control?

If so, and if DJI fix this bug, I'm tempted to leave the set up as is so I have a manual return to home AND gain control using X3, (the best of both worlds!)?

Thanks,

Steve Q :)
 
Last edited by a moderator:

MombasaFlash

MombasaFlash

Heli's & Tele's bloke
steveq said:
....2. Calibrate the compass. This should only have to be done once at each new location...
Click to expand...

What's all this about recalibrating the compass at each location? Never heard of that before - except perhaps when you change continents.
 

gtranquilla

gtranquilla

RadioActive
Recalibrating Digital compass in GPS module

DJI does not explain this at all.

Use the following tool to determine if/when to recalibrate your digital compass.......

In general the angle of declination changes substantially as you move east or west...... (North and South? not so much)
but also the angle of declination shifts over time..... its the liquid iron core of the earth that flows and allows for the shift which is apparently in response to the van allen radiation belt etc. etc.

And printed maps showing the angle of declination are DOA documents (dead on arrival) so that is why you need the following "living maps".:shame:


http://magnetic-declination.com/

MombasaFlash said:
What's all this about recalibrating the compass at each location? Never heard of that before - except perhaps when you change continents.
Click to expand...
 

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