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Compass calibration

Discussion in 'Phantom FC40 Discussion' started by leekiya, Mar 21, 2015.

  1. leekiya

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    Every time I do a compass calibration after the warm up procedure I power down and then power up again before take off. Do I need to do this or can I just take off after compass calibration. I am all ways worried the calibration and lifting it up will have upset it's homelock or something so that's why I start again.
     
  2. J Dot

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    No need to power cycle,
    I do this ( p2v )
    1) turn on tx, ( range extender p2v )
    2) turn on bird ( f40 )
    3) let bird boot up, 30 secs or so
    4) compass calibration
    5) wait for sats, and home lock
    6) lift off ( 8-10 feet / 2-3 meters up )
    7( look for STABLE HOVER ) if good have fun,
    If hover unstable, or anything weird, LAND
    RECALIBRATE COMPASS, try again.
    8) I do compass cal only once in a while or when
    I go far away ( more than 50 miles or so )

    But no need to power cycle after calibration!

    Hope this helps!

    Take care, Fly safe!
    J Dot
     
  3. IflyinWY

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    What J Dot said and,

    Put the Phantom back where it booted, facing the same direction, so it doesn't get confused at liftoff.

    Compass Calibration:
    I see some folks standing in one spot and rotating with the Phantom being held in an outstretched arm.
    I prefer to pivot myself around the Phantom while holding it directly over the point where it booted.

    I've had serious issues resulting from doing the Compass Dance over buried power lines. :(
     
  4. Monte55

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    I have 2 of the P1 Phantoms. I understand they are so close to the FC40 other than frequency used. This is what I do and never had a problem. First flight of the day...do a compass calibration. I am in Naza mode with IOC enabled. Anytime you change something on quad like having a gps tracker, add or remove camera etc....do the dance. Also I don't understand doing the compass dance first. I always wait for my quad to give me the 2 sets of quick green flashes indicating course lock and home lock are good. I, then do the compass calibration on the first battery...even if I am in the same flying area. This has always worked for me and I have had no problems. After liftoff, I always test cl and hl and if ok, go fly and have fun.

    PS...IT is important to remember which way the quad is facing at start up for course lock to work as you would expect.
     
  5. J Dot

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    I am in an area, where I do not get good GPS signals. Some days are better than others,
    But unfortunately, it can take up to SEVERAL minutes to gain 6 for sat. And home lock!
    So I do compass first , just to kill time, as I seem to have plenty! Lol.
    I have never had an issue this way either! I guess it would be more of a preference thing?
    Whatever is comfertable for you!

    I also spin just the phantom during compass cal, he is right some hold bird while they spin round!
    Neither way is wrong, it all seems to reach the same desired outcome, a nicely calibrated machine!

    Take care, Fly safe!
    J Dot
     
  6. Monte55

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    I guess I have been lucky getting gps lock. I'm in Missouri. Cold start may take 45 seconds or so on first battery...then do compass dance. Second battery..no dance....2 sets of green flashes. ..about 30 seconds. Ready to fly. Maybe I'm spoiled.
     
  7. Lonewolf

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    Interfering with the initial startup/bootup to do a compass calibration is not the proper way. Letting the craft finish its startup/bootup routine THEN, doing the compass calibration is the proper way. For some reason, people seem to think that the compass is directly related to the home point. It isn't. All the compass is for is to let the Phantom know where on the planet it's at. That's all. You can take the Phantom 10 miles away and fly it with no problems without recalibrating the compass. It still knows geographically where it's at from the first compass calibration you did 10 miles back. Of course if you were to fly it 100's of miles from the initial calibration, it most likely will have an issue.

    Why then does the first set of flashing green lights tell you its found its home point before you've even did a compass calibration then? It's just NOT necessary to interrupt the initial startup/bootup routine. IMO, interrupting it is just asking for issues to occur because of interrupting a crucial routine.
     
  8. Monte55

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    As I understand, the first set of quick green flashes sets course lock. Second set of flashes is recording home point but not locked in till you start the motors. I agree to let the quad sit there undisturbed on a level surface during power up to let the gyros etc to stabilize. Then, if needed, calibrate compass.
     
  9. Lonewolf

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    No. The first set of rapid green flashes indicates it found your HOMEPOINT. The second set of rapid green flashes indicates it found the GPS satellites. Course Lock is when you are facing a certain direction and flip the switch to course lock it will follow that line of sight for you.

    As an example, in GPS, if you face the Phantom to the North and push the stick FWD, it will go FWD to the North, pull back and it will come back to the South. In Course Lock, however, if you're facing North then rotate and face the Phantom East and are in Course Lock when you push the stick to go FWD it will STILL go NORTH instead of going EAST in the direction it's now facing. Pull back and it will go STILL go SOUTH even though it's facing EAST.
     
  10. Lonewolf

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    I always start my compass calib facing my North magnetic declination. -8ยบ of North. Then I turn the craft counter-clockwise for both horizontal and vertical. By doing so, I eliminate the "Toilet Bowl Swilling" effect you sometimes see when in hover. (It won't hover steady. It will go in a slow small circle usually in a clockwise rotation while in hover.)
     
  11. Monte55

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    Home point and finding gps sats is the same thing thing. You seem to be a bit confused although some of what you say is correct.
    BTW when do You think it get's course lock?
     
  12. Lonewolf

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    Hmm. I see now what our issue is. Sorry, first set of rapid green flashes means it found forward direction. Which is the SAMETHING as Course Lock. The 2nd set of rapid green found and recorded the Homepoint.

    I thought you meant Course Lock being when you switch to CL on the S2 switch which will then allow you to maneuver the Phantom differently.