Strange behavior of Altitude Hold :( Help needed

Discussion in 'Cinestar 8' started by David Tivadze, Oct 31, 2014.

  1. David Tivadze

    David Tivadze Member

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    Hi ALL,
    I will try to say it one by one.
    1. I start the motors having all GPS switcher OFF, The MODE on OSD screen says FREE. As soon as I start the motors, immediately after word FREE there is another word (manual). So the I have MODE: FREE (manual). Whem I fly the copter I switch the MODE switch to PH, and I also have not just PH, but PH (manual). I have no explanation to this fact ( all trimers are at their central position), and I do not know if this issue has a connection with my MAIN problem, which is:
    2. I raise the copter at about 7 meters and switch the AH ON. Immediately copter starts to go down, I move a gas stick a little up, and reach the hover position. Now the copter stay and hold the altitude.
    3. Here strange things starts. I switch OFF AH and the copter immediately start to go up, very quickly. I switch off the AH. It stops to go up and hold the altitude. If I switch AH OFF again, the situation will be the same: the copter will go up very quickly and if I switch AH ON it will stop and hold altitude.

    It is my second fly with this new cinestar. The point is, that first flight was excellent. After that I made some tunings in MKTOOLs and now I have this problem. At my first fly the only problem which I had was some altitude loss when I switch the AH ON. It was not a little lost, about 1 m. It was the only problem. But now I really do not know what to do and how to begin to fix this strange thing.
    Thank You in advance for any help!
    Regards
    David
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Can you upload some screen images of the Easy and Misc setup windows from MK Tool, please David.
    Also, just as a convenient, can you use save the .mkp file with all the settings and post that too.

    Thanks
    Andy.
     
  3. David Tivadze

    David Tivadze Member

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    And here is the .mkp file
     

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  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmm. I see links to a web site in .ru but no images. Did you upload the images or try to paste a link? (You need to click on the Upload a file button at the bottom of the message window.

    Thanks
    Andy
     
  5. David Tivadze

    David Tivadze Member

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    May be now it will be ok :)
    David
     

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  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yes. If you can see them in your posting, then they're good. I'll have a look at them in a few minutes.
    Andy
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    On the Easy Window, try changing the Stick Neutral Point to a value of zero -- that enables the automatic AH, so it does not matter what the stick position is when you enable it -- the Flight Control board calculates the necessary amount of gas to hover at the altitude setpoint.

    Once you're in AH, then the throttle stick doesn't control the throttle directly but acts as a "go up" or "go down" controller.

    Andy.
     
  8. David Tivadze

    David Tivadze Member

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    Thank You, Andy. I replaced Stick neutral position point 127 TO zero. As for other parameters in my settings You think they are OK, don't You?
    David

    I can test the changes only tomorrow, because there is now midnight here :)
     
  9. David Tivadze

    David Tivadze Member

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    Forgot to describe one more "strange" ( may be not) thing. At very first time, when I switch AH on, copters goes down , and if I will not move gas stick a little bit up, it will go completely for landing. When I move the stick up and find the hover position and after that copters hold the altitude there.
     
  10. Holger Göhr

    Holger Göhr New Member

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    I think you emergency gas is at 65% a bit on the low side.( = 65% of hover throttle! the copter will fall straight out of the sky)
    I'd also set the hook on 'do not start without GPS fix' and the SD card.
     
  11. David Tivadze

    David Tivadze Member

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    Thanks Holger. I already corrected the emergency gas value, now it is something like 94%.
    Anyway, hope emergency moments never come ;
    Regards
    David
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Agreed. Holger beat me to the punch (I was in a meeting).

    On the MISC window my comments would be:
    1. I would also avoid Carefree mode like the plague. Do a search on the forum for other threads and why I think it's a really bad idea to use Carefree.
    2. Under voltage at 14.5 is *very* conservative. You may choose later on to set it to 14.4v.
    3. Emergency time: Increase to the maximum (I think it's 247).
    4. Emergency gas: 95% (always be sure that the "Use Vario Control" is checked and the % sign is present!)
    5. Compass error, SD card missing, GPX fix missing: Personally, I check the all. I really don't want to be flying with a compass error or without an SD card or a GPS fix!

    Andy.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sadly they will come, David.

    Andy.
     
  14. David Tivadze

    David Tivadze Member

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    Thank You Andy for Your comments. Tomorrow, if no rain, I will test this changes. Remarks about the emergency parameters are definitely very important. As for my problem, I mean strange behavior of the switch AH , I hope the changing stick neutral point will solve the issue I had.
    Will report results tomorrow after fly.
    Thank You again
    Regards
    David
     
  15. Holger Göhr

    Holger Göhr New Member

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    Andy, I think you meant the right thing, but 'ignore compass error' should actually be unchecked, as you do not want to ignore compass errors at start up (or just in special circumstances).
    GPS and SD card checked.
    Holger G.
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ooops. You are correct Holger. Apologies.
    I don't know why Holger/Ingo invert the logic of that setting.

    Andy.
     

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