Attitude status bad (white led double flash)

[Sebas600]

Been flying a couple of times now but I deep getting the double white LED flash every one in a while.

Has anyone had this? Is this a big problem? Is it dangerous?

It does't stay long like that. when landing it always goes away. gets it in att. and gps att.

my gps is locking on in 30-40 sec to no red flash (cold boot) but it is near other electronics but shielded.

View attachment 1648

thanks for any help on the subject

Sebas

 

[Droider]

@Sebas.. nice looking build.

I get it quite regular on my little quad but it does not seem to make any difference as to flight performance.. I keep reading the manual but still not sure of the implications of the white light every now and again.

Maybe some one from DJI can elaborate on the significance of it

Dave

 

[BorisS]

Seba there are a lot of complaints on Rcgroups at the moment of getting white flashes since firmware 4.22. I am still on 4.0 with my setups do i cant back it up. I am pretty sure that you mounted you IMU correctly and didnt use any vibrations dampeners to mount it or similar, anything that wouldnt give it a solid connection to the frame.

Boris

 

[vislaw]

They've pulled down firmware 4.22 until they can check out the reported problems. I'd suggest going back to 4.2 if yhou are on 4.22 now.

 

[Sebas600]

Thanks for all the replies on the subject.
I still have the 4.2 firmware on the setup.
The IMU is mounted with foam tape to the frame as described in the manual. is this wrong? should the connection be solid?

Sometimes i can see some twitchy movement when hovering, no white led flash, fast small corrections. but this isn't good for video quality.
what could cause this? the props are balanced. vibrations are minimal.

View attachment 1652View attachment 1653View attachment 1654

 

[nisouck]

If I have a look onto manual I can see into manual page 26, for atti or GPS mode :
for a double white flash: Status fair
for a triple white flash : Status bad


So where is the problem IF NO OTHER manifestation or problem ??

 

[Sebas600]

There is no other manifestation of the problem...
that is why I'm asking... would be stupid not to ask.
I assume the system is not displaying this for no reason...

there is no visual sign of anything going wrong. behaving different or extreme drifting what so ever.
there is no clear sign of this happening when doing a particular movement or anything.

this is why i'm asking, rather now then ask when it has plummeted to the ground and then ask...

 

[BorisS]

Seb dont know if you have seen this but its a good explanation:from RC groups

Just got it from Chinese forum and translate roughly

Regarding White LED flash

White LED is the signal of IMU status, which has nothing to do with firmware version. So using new firmware won’t cause more/less appearance of white LED.

Logic meaning of white LED flash:
1. Error value between GPS data and IMU computing, which happens when: A, GPS signal unstable. Sometimes get adequate satellites with low reliability, which differs too much from the IMU computing. B. Fierce movement during flight makes the sensor in IMU out of working range, the computing result of IMU is different to GPS data. C. Vibration causes noise to IMU.
2. Error value between Compass data and IMU computing, which happens when: A. Compass not calibrated correctly. B. External interference to compass after successful calibration. B. Fierce movement during flight makes the sensor in IMU out of working range, the computing result of IMU is different to GPS data. C. Vibration causes noise to IMU.
3. Error value between barometer and IMU computing, which happens on crafts with high vibration.

Solution:
1. Intermittent white LED is no problem, especially when doing fierce movements. Hold the position for a while and the white flash would be off.
2. When searching GPS (3 red flash to 1 or none), it is normal to have white LED flash, even the craft is on the ground. If everything ok, the flash should stop soon.
3. In some cases, even though GPS is adequate (no red flash or just 1 red flash),but it’s not reliable, and the LED might flash in white. If the craft is still on the ground, pls fly carefully as it may not hold position in GPS mode, drifting/hunting, showing severe attitude correction of the craft. Pls do not fly in GPS mode in this case. What’s more, the GPS signal strength varies from time to time even on the same spot.
4. If white flashes happens when you yaw, even very slowly, pls recalibrate the Compass. Pls be noted that it is not necessary to calibrate at every new flying area unless components is added/removed, or mounting location changed no matter they are electric or mechanical. Since multirotor is a highly integrated system with different components, pls make sure the GPS/Compass is far from noises, interference, electronics or wires with high ampere.
5. Vibration will cause white LED flashing, too. The high frequency vibration might be result from unbalanced motor or props. So pls check all mechanical connection, and balance on motors and props.

The above is the reason and solution on white LED flash. Intermittent flash is normal, which won’t matter during flight. For continuous and frequent flash, pls check your craft according to the above and fly carefully.

 

[Sebas600]

Great! thank Boris, this is the answer is was looking for! going to check accordingly.

thanks again :02.47-tranquillity:

is there a trick for aligning the IMU and GPS?

Have put the GPS on a small pole now. still inside the dome but max up.

 

[RTRyder]

Thanks for all the replies on the subject.
I still have the 4.2 firmware on the setup.
The IMU is mounted with foam tape to the frame as described in the manual. is this wrong? should the connection be solid?

Sometimes i can see some twitchy movement when hovering, no white led flash, fast small corrections. but this isn't good for video quality.
what could cause this? the props are balanced. vibrations are minimal.

It should be solidly mounted, the IMU has vibration isolation inside the case. The twiching is another problem entirely and I've found through much trial and error that it is directly related to the props in use. On the CineStar 6 if I use Graupner 11 x 5 props the twitching/wobble is pretty much nonexistant, if I swap to APC 11 x 4.7 I can see a slight side to side movement in the recorded video even though it looks pretty stable from the ground. If I swap to APC 12 inch or Xoar 12 x 5 props the wobble is much more apparent, easily seen by just watching the CS in a hover high enough to be out of ground effect and also more pronounced in the video. My theory is that the WKM cannot compensate correctly when the props have excess lift for the weight of the craft or a large surface area on the blades that resist fast speed transitions. If you compare a Graupner prop to an APC it's very easy to see the difference in blade design and the Graupners are a lot stiffer. The Xoar fare better than other 12 inch props I've tried I think largely because they are also very stiff and have a much smaller surface area on the blade as well when compared to the APC slow flyer props.

I'm trying a couple things with the CineStar to see if I can eliminate the twitch and wobble. Most large multis have issues with yaw authority and control response to some degree because of the size, the CS being 825mm motor to motor certainly falls into this category. A solution that Mk has used with their XL frames is to incline the motors approximately 2 degrees towards the direction of rotation, I did this last night on the CS and will be testing it today to see if it does indeed help. The other thing is to try out a set of 12 inch APC thin electric props which have a form similar to the Graupner. The last thing I will try if neither of these help is to reflash the firmware on the ESCs with a more multirotor friendly version that decreases response time and eliminates throttle filtering that was implemented for use on planes and helis, but I'll save that for a last resort mainly because if it makes things worse there's no going back to the original firmware so that would mean a new set of ESCs.

Ken

 

[BorisS]

Ken you would the the flash with you DYS or ? do you have a source to the Firmware i would try it with my 20A dys on the CX. If it goes wrong it dosent really matter since i wanted to change them anyways because of the clicking i get from them, which i dont like because i dont know the reason and that makes me nervous.

Thanks

Boris

 

[RTRyder]

Ken you would the the flash with you DYS or ? do you have a source to the Firmware i would try it with my 20A dys on the CX. If it goes wrong it dosent really matter since i wanted to change them anyways because of the clicking i get from them, which i dont like because i dont know the reason and that makes me nervous.

Thanks

Boris

The clicking is caused by the wrong timing being set for the motor in use, it can be reprogrammed by using a Turnigy programming card on the DYS (same ESC under the shrink wrap). The AXI I have on the CS were clicking badly on low timing, I reset it to high timing and the clicking is gone. If you want to try the reflash all the information you need is here... http://www.rcgroups.com/forums/showthread.php?t=1513678

Ken

 

[Sebas600]

Thanks for the in tell on that one Ken.
ordered the Graupners to test if this will fix the problem for me.

Sebas

 

[BorisS]

thanks ken, have them on mid at the moment will try high. Is it a rule the motors will produce more heat at a higher timing or do they just produce more heat with the wrong timing ?

 

[jhardway]

good stuff guys I just want to say thanks, I find the information help and good to know.