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Weird AH and stability problem with MK FC 2.5 and BL Ctrl 3.0

Discussion in 'Electronics' started by Ozkan Erden, Apr 16, 2014.

  1. Berndt Frogner

    Berndt Frogner New Member

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    Ozkan, I'm interested in your experiences with BL 3.0/FC 2.5 and different motors, I'm about to give up on the whole MK set up after using MK on several builds in the past. I'm trying to get the new combo to work with Tiger 4012-9 motors which I understand should be a workable config, what I experience is that I get 5 motors to start up when running motor test in Koptertool, while 3 'studders' and never 'fire up', I played around with what seems to be endless variants of BL configs with PWM values, timing, frequency etc (btw, has anyone seen any docs around these settings from MK ?), I have had the BL board returned and inspected by MK Germany and should be fully functional. My own very unscientific analysis is that what differs between the 5 working motors vs. the studdering 3 is friction. If I hand spin the 5 working motors they have less friction than the 3 studdering ones, could it be that the tolerance of the 4012's is off and that the margin between working and non-working is very narrow when using 4012 with BL 3.0 ? This alongside other issues reported around the new MK stack does not build confidence.

    On another note, why did you move away from Herc III if it worked great for you, I'm actually looking to move into that direction in combo with DJI A2 ?

    Best, //Berndt
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    Berndt,
    Have you updated the firmware in your BLs to 1.02d and followed the advice of MK to increase the StartPWM to 4?
    It seems to me that if there is a physical difference in your motors’ friction when turning them by hand, you have an issue with your motors, no?
     
  3. Berndt Frogner

    Berndt Frogner New Member

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    Steve,
    have not done the BL upgrade (which of course seems like a reasonable first step...), but since 5 out of 8 spins I didn't feel comfortable not understanding why this is the case even with the old FW. That alongside the fact that BL FW upgrade is not the swiftest process, but yes you are right, I will try it.

    Have tried all start PWM values (1-7) and in all timing combinations as well, interesting observation is that regardless parameter setting all motors behave the same, and yes, did 'Write' to EEPROM between changes ;)

    As for conclusion, yes, right now I lean towards it being a motor problem, but these are all new out of the box, and getting 3 (and really 4 because 1 is only starting after 3-4secs) out of 8 Dead On Arrival rises an even bigger question, what about manufacturing quality of these motors, how can I trust them in a production environment.
     
  4. Berndt Frogner

    Berndt Frogner New Member

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    Double checked and found my BL board reads version 1.02d so am I right in assuming that I have the current FW, is there a way to check it ?
     
  5. Ozkan Erden

    Ozkan Erden Distributor

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    Hello Berndt,
    I think it's not possible to see which firmware you are suing through MK Tool for BL Ctrl. It's possible for other components actually.

    First, I'd recommend you to update to the beta BL Ctrl firmware:

    http://www.mikrocontroller.com/files/upload/BL-Ctrl3_MEGA168_V1_02d_SVN799.hex

    Changelog:
    1. Improved motor-start
    2. internal speed limitation
    3. increased commutating speed (Max RPM is 200.000 devided by the number of magnets -> 16.666 RPM if you have 12magnets)
    4. Prepared for redundant FC-Operation
    5. Small bugfixes

    I tried BL Ctrl 3.0 with several motors including Tiger MN4014 KV400 which is very similar to yours. After updating the firmware, I setup timing to 28 and PWM start to 1 for all BL Ctrls and they are working flawlessly. The same settings for KDE 4014XF.

    I had the similar stuttering problems with motors but after the firmware upgrade and correct timing & PWM start settings, all motors are firing at the same time.

    As for Hercules III, I wasn't able to read the amps consumed on the telemetry screen; I could only see the voltage. Normally it's enough but, I am very used to see the amps consumed parallel to the voltage.
    For migrating to DJI: I have been to that path and came back to MK. Maybe, setting up a MK is not as user friendly as DJI but just integrated telemetry is one of the few reasons to choose MK over DJI, for me. When you have a problem, you can diagnose the issue with internal logging and MK provides lots of very valuable data to interpret.

    Lets solve the problem. You can follow this thread for upgrading the BL Ctrl firmware:
    http://forum.freeflysystems.com/index.php?threads/my-new-mk-heavy-lift-copter-project.3091/page-15

    It will be also helpful if you can send some close-up pictures of your setup.
     
  6. Berndt Frogner

    Berndt Frogner New Member

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    Thanks Ozkan, it's clear I need to do the upgrade even if I suspect I have the correct version (the physical board itself has a sticker with version 1.02d on it) since it seems impossible to read current FW version.

    Will also add a few pics or a video to visualize my issues.

    Will get back shortly when done and report back, btw tried your PWM and timing settings in the current set up with no difference.
     

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