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Motors start but I can't throttle up

Discussion in 'Electronics' started by Morgan Friedland, Sep 13, 2012.

  1. Morgan Friedland

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    Yesterday morning I went out to for a quick fly at the park. I did my pre-flight checks (Battery voltage 16.1, Transmitter looks good, Prop checks, Power on, compass and gyro calibrated and motors started)

    I then give it some gas and the motors spin up about 5% and go back to idle even though I keep increasing the throttle. I go full up and down on the throttle but the motors keep repeating; Increase about 5% and then back to idle. I power cycle everything and try again. Lights on the ESC's are green. Compass and gps are green. No buzzer noises.

    I go home and connect MK and examine all the settings. Everything looks good. TX is showing full servo motion on all channels as normal.

    I pull the SD card from the Navi board and realize that nothing has been logging to it. Hmm. Do I need to format the card with a particular file system? It is currently MS-DOS Fat32.

    Any ideas would be greatly appreciated.

    Morgan
     
  2. Adam Paugh

    Adam Paugh Distributor

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    Hello Morgan,
    Check to see that your alt. hold/gps switchs are in the off position on your transmitter prior at take off. Also check in the MKTool in the "Misc" tab that the undervoltage setting is at "33"...or at 3.3v/cell.
    Don't think the SD card would have much to do with it although MK does state that the card should be FAT16 formatted.
    Greetings,
    Adam
     
  3. Morgan Friedland

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    Alt. hold/gps switches are off. MKTool Misc tab showed 144 (14.4v). I changed it to 33 and wrote them to the FC. Started engines and no change. With Gas all the way down the motors idle normally. As soon as I gas up a bit, the motors actually decrease in rpm and stay there.

    Thanks for the ideas.
     
  4. Howard Dapp

    Howard Dapp Active Member

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    For safety, If you haven't done so already, i'd remove the props...just in case the problem decides to fix itself during problem solving. Next i'd disconnect gps/compass from the flt control board, then I would disable gps, compass and pressure sensor in mktools. Any change?
     
  5. Morgan Friedland

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    I yanked GPS and Navi cables from FC. Turned off altitude hold, gps and all other navi functions from MKTools. I wrote it all to the FC and hen it would not start. Just got beeping errors.

    I now have a SD Card in Navi board formatted FAT16 but still not logging. I will pursue finding out why this is happening and hopefully get some diagnostics.

    As another troubleshooting idea, I saved my current MKTool configuration and started over with the defaults. Set my controller to Graupner HOTT. Wrote config to the C8 with same results. Motors actually run faster with gas all the way down. Move it up a little and the motors spin down to a fixed RPM that is a bit slower.

    I am starting to wonder if it is my TX. A few days ago I cracked the LCD panel when my thumb pressed against it too hard. (It didn't take much!) Anyway, my LCD screen is unreadable so I am not able to adjust it at this time. Replacement parts are on the way so I may be stuck until then. Perhaps I accidentally made some changes although it shows up in the channel tab of MKTools as working correctly.

    I'm trying to think about what changes I made to the bird and I think I may have upgraded the firmware from 88m to 88n the night before although I am not certain. I will get the logging to the SD fixed so that I will have some more data.

    Again, thanks for taking a stab at it. Looks like I will have to have my daughter jump off the roof holding the 3 axis gimbal with my new STAB boards so I can see how well they work. ;)
     
  6. Josh Lambeth

    Josh Lambeth Well-Known Member

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    The sd card issue is a common one. I had to go get a new card for it to work.

    In ml tools try checking the boxes for ignore compass errors and sd card missing on startup and see if that works.
     
  7. Morgan Friedland

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    Thanks. I purchased a new card and that seems to be logging correctly now. I have checked the boxes to ignore errors and sd cards. The weird thing is the motors start just fine but will not throttle past 40 on gas. It works all the way up to 39 and then the RPMs slow down to a fixed speed when gas is between 40 and 240. It will rev up when I try to nick/roll and I can spin the motors fast when performing a motor test in MKTools. Clearly all the hardware is working. Perhaps I have a software configuration corruption where it doesn't want to take off for some reason?

    Has anybody ever downgraded their firmware? I'm currently running 88n and 24n. I think this problem started when I upgraded from 88m and 24m. Below is my settings.ini pulled form the SD card. There are no other files nor a log folder. Is that only created when you are able to lift off?

    ######## MikroKopter configuration file ########
    #------------------------------------------------------


    # KML logging interval in ms (0 = disabled)
    KMLLOGGING = 500

    # GPX logging interval in ms (0 = disabled)
    GPXLOGGING = 1000

    # max. altitude in m
    MAX_FLYING_ALT = 0

    # max. range in m
    MAX_FLYING_RANGE = 0

    # Auto-descend range in m (0 = disabled) (only comm. License)
    DESCEND_RANGE = 0

    # GPS SBAS mode (0 = off, 1 = on)
    GPS_SBAS_DGPS_ON = 1

    # minimum time of the Waypoint-Event value (seconds)
    MIN_EVENT_TIME = 2

    # GPS configmode (0 = off, 1 = on)
    GPSAUTOCONFIG = 1
     
  8. Morgan Friedland

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    I Reinitialized the EEPROM. Everything looked good in the terminal but didn't fix the problem. I was going to downgrade the firmware to 88m /24m but it looks like it is no longer available online. Can anyone email me a copy?

    Grasping for straws....

    Morgan
     
  9. Morgan Friedland

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    Thanks. I was able to downgrade to 88m/24m but the motors still will not rev up beyond 30rps. Tonight I am going to disconnect and check everything again. The only thing I have not been able to troubleshoot is the MX-20 transmitter. Seems unlikely that would be the problem as I can see the throttle values in MKTools Is there any way to get better realtime diagnostic information form the flight controller? Morgan
     
  10. Arthur Vieira

    Arthur Vieira Flight Squad

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    When you test the motors via MK Tools, do they work?
    When you pump up the throttle after calibrating the gyros, do the MK Tools shows Channel 1 moving up?
    Have you checked if you are on the right MK Model Memory on the MK? Maybe it's on a unconfigured model?
    When you calibrate the Gyros, do you hear any different beep?
     
  11. Morgan Friedland

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    Testing motors in MK Tools works perfectly. One at a time or all at once.
    Pumping up throttle after calibrating shows channel 1 moving up with the full range of motion.
    MK Model Memory has been confirmed. It is the correct model.
    Calibrating Gyros gives the normal two beeps. Once calibrated, I can start the motors.

    One interesting note: When I unplugged both ribbons between Flight Control and Navigation boards as well as disabling the gps, altitude hold, position hold, it would not start. Would receive continuous beeps (2 per second I think). I never could start the motors without GPS and Navi connected.
     
  12. Josh Lambeth

    Josh Lambeth Well-Known Member

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    And you have the ignore compass error on startup checked? Has the copter flown before? Try recalibrating the ACCs. Up and to the right on the throttle then calibrate gyros normally. Make sure copter is perfectly level.
     
  13. Howard Dapp

    Howard Dapp Active Member

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    Is that your only bird? pull the rx and try it on another craft using the same tx.
     
  14. Arthur Vieira

    Arthur Vieira Flight Squad

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    Double check if the Carefree mode is not always on and also check if the Altitude mode is not in Vario all the time, if it is check the sensor on the FC if one of it's "legs" isn't broken.
    Good luck.
     
  15. Morgan Friedland

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    Eating some crow here. You were correct. The model memory in MK was set to 3. I somehow incremented it from 2 to 3. Clearly I need to read the manual as I still have no idea what this function does.

    Thanks to all who chimed in with their ideas. I could not have fixed this without your help.
     
  16. Arthur Vieira

    Arthur Vieira Flight Squad

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    Morgan,
    Glad I could help.
    The MK has 5 Memory Settings, they are used for different flying configs, for example. You can have a smooth setup in model memory 3 for filming and a more aggressive setup in memory 4 (Pid settings, etc).
    For changing the model memory is very simply and sometimes we do it without knowing. If you move the Right Stick to some positions during Gyro calibration a memory is selected. Take a look at this picture: http://www.mikrokopter.de/ucwiki/en/Mikrokopter-Get-started#Calibrate_sensors_and_choose_Setting
    In MK Tools you can select the memory on a combo box on the bottom of the window, it's just a number (1 to 5).
    To check what memory you are pay attention to the number of beeps the MK does just after Gyro calibration, normally it beeps 3 times - that's for memory 3.
    Good luck and nice flying ;)
     
  17. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Morgan: On that same link that Arthur sent you (http://www.mikrokopter.de/ucwiki/en/Mikrokopter-Get-started) it also says: "For beginners it is advisable to start with setting 3. In this setting, the joystick movements are not too sensitive."

    So I'm a bit puzzled why you were having problems with it set to 3 when that's the recommended starting value?

    Andy.
     
  18. Morgan Friedland

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    Well it turns out it wasn't the settings number after all. I thought the bird was fixed late one night when I started it inside with props on. (I know I know but I was feeling lazy and running low on nylon nuts. I have it tethered to the desk with a strap so it will not fly)

    I started the engines normally and gave it some gas. The engines revved up much higher than in the past. What I didn't know is I was inadvertently giving it some yaw which caused half the motors to spin much faster. Hence, I thought it was working.

    Not until Saturday afternoon did I finally get the STAB boards installed did I realized it still was not working. After some depressing moments, I decided to calibrate the compass and try one last time. I had actually never been able to calibrate the compass before as my hearing is shot in the high frequencies so I can't really hear the tones very well. I got my wife to translate the buzzer noises and successfully calibrated. Engines start and lift off!!!. 3 days wasted!!!!!
     
  19. Dwayne Griffiths

    Dwayne Griffiths New Member

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    Thanks for the follow up post! I just finished building my Cinestar 8 last night and was doing some initial tests and I experienced the same issue you described. I have yet to calibrate my compass, that will be the first thing I do when I get home.
     

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