Pan issue with Graupner MX12 & Radians

Discussion in 'Radian' started by Glenn McKenna, Sep 9, 2013.

  1. Glenn McKenna

    Glenn McKenna New Member

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    Hi,
    I'm having issues with the pan radian where it connects for about 10 seconds (and I have a sort of 'jerky' type of control with it) and then it just cuts out entirely and I have to power cycle everything to get it back to that spot again - where it then just does the same thing again. I feel like I've tried everything and have read through the forums and haven't found a similar issue that gets resolved. Any thoughts/input to go on from here? I'm about to flash the firmware on the radians to see if that helps. Oh - I've also tried assigning pan to the different radians to make sure it's not an issue with just one of them but the same thing happens no matter which radian I use.
    Thanks for any feedback/input,
    Glenn
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Can you tell us more about how you have the Radian wired up -- more specifically, do you have it connected to the same power supply as the servos? If so, these kick out a lot of electrical spikes down the +5v wire and it could be that these are causing problems.

    So can you describe the electrical set up and how you have the Radians wired up, please?

    If you copy and paste the questionnaire at http://forum.freeflysystems.com/index.php?threads/radian-issue-please-read-this-first.744/, you can then fill in your answers and be sure you've answered everything. :)

    Thanks
    Andy.
     
  3. Glenn McKenna

    Glenn McKenna New Member

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    Hi Andy,
    first off - great work on that tutorial video for the Cinestar, very helpful indeed.
    As for the Radians, yes, they are both connected to the same power supply - however, we do have the BEC wired in to pull the amps down which I thought was enough to help with that issue - not sure. Basically though, we've got the battery going into the BEC and then from there, right into the Graupner MX12. From there, out to the Pan Radian then Roll then tilt Radians - wired the same as it's described in the Freefly Radian manual. The roll and tilt work fine, but the roll does seem to be getting too much power as we need to pull the gain all the way down to 10, otherwise, it kind of moves very quickly/crazy and then faults out and we no longer have control. At the gain setting of 10%, it at least doesn't cut out - it's just still not very responsive to the controls. I've also swapped out the pan and roll Radians to see if it was an issue with one specifically but that didn't work either. It feels like a setting in the Graupner but we've tried all we can within that as well as with the Radian software. My last test to try is to flash out the firmware on the Radians and see if that does anything but I don't feel that's likely to make a difference.
    Thanks for the response and let me know if you've any thoughts.
    Glenn

    Aircraft Type: C8
    Gimbal Type: 3 Axis
    Radian Type ( 1, 2 , 3 axis) 3
    Gimbal Power source: 1200 mAh Lipo
    Gimbal Radio Type: Graupner MX 12
    Radian Communication Protocol (S.Bus, PPM, PWM, Spektrum) PPM

    Connections: Change these to match your setup
    Roll Sensor:
    Port
    1. power from Pan sensor
    2.
    3. To Tilt sensor
    4. To Roll Servo

    Tilt Sensor:
    Port
    1. power from Roll sensor
    2.
    3. power to HDMI convertor (although not in use during this trouble shooting phase)
    4. To Tilt Servo

    Pan Sensor:
    Port
    1. GR-12 receiver and power.
    2.
    3. To Roll sensor
    4. To Pan servo

    Symptoms:
    can connect to Pan Radian but it doesn't perform properly - ultra sensitive and uncontrollable.

    Video coming shortly.
     
  4. Gary Haynes

    Gary Haynes Administrator
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    What voltage are running out of the BEC? Also photos of your setup or even cellphone videos always help.
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Glenn:
    Thanks for the compliment on the DVDs! :D Glad you found them helpful.

    It still has that funny feeling that this might be a power supply/noise issue -- especially if you have swapped Radians and the problem remained the same.

    I would start by simplifying the system. For example, feed the output from the receiver and power to just the pan Radian and sensor. Don't even have the tilt and roll Radians and servos connected up. See if the problem still persists.

    If it does, can you hook up the Radian software and check to see what's happening with the Slew control for the Pan Radian-- is it also twitching left and right -- if so, the Radian is really seeing bogus "commands" to twitch. If it's not, then it still might be electrical noise on the +5v line.

    Bear in mind that if you have the gimbal resting on your bench, the Pan servo will spin the top part of the copter -- to really check what the Pan Radian and servo are doing you need to suspend the copter by the battery plate so that the gimbal is not in contact with the bench. I've seen people do this from a hook in the ceiling, or even just using two chair backs with the gimbal in between them (the chair backs are fine for this test, but not good for balancing the entire Cinestar/gimbal combo, of course).

    After that, assuming the problem didn't go away, you might want to consider swapping out the pan servo. That might just be the cause of the electrical spikes that are causing the problem.

    If the problem goes away, then add back in the Roll Radian and Servo and test again.

    Please post results of what you find.

    Andy.
     
  6. Glenn McKenna

    Glenn McKenna New Member

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  7. Gary Haynes

    Gary Haynes Administrator
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    Glenn we need to know what the voltage is on the output side that is going into the receiver. The Castle BEC is adjustable through software and the factory default is usually 5.1 volts. But you need to check it to make sure what voltage is actually set.
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Just to augment what Gary said, Glenn, you need a CastleLink USB adapter (http://www.castlecreations.com/products/castle_link.html) and the Castle Link software (http://www.castlecreations.com/downloads.html). You install the software on a PC, connect up the cable to the BEC, and then you can set the output voltage.

    I think you may have confused the voltage with maximum current value. (If you are not familiar with the terms, one often-used analogy is that of a garden hose. Voltage represents water pressure. Current represents (as the name implies), the volume of water flowing through the hose -- or in this case, the maximum flow.)

    Hope this helps.

    Andy.
     
  9. Glenn McKenna

    Glenn McKenna New Member

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    Thanks for the suggestions Gary & Andy!
    I had no idea that BEC was programmable - and am also surprised that it doesn't come with the usb connector (or at least mention it - guess it's common knowledge for most). Regardless, I have since order one and shall post results as soon as it arrives.
    Thanks!
     
  10. Glenn McKenna

    Glenn McKenna New Member

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    Ok - several weeks later and the issue has finally been resolved. I have yet to look back through the build process/manual for the gimbal, but it turns out that the problem was with 4 screws - and a lack there of. On the star plate that attaches the gimbal to the bottom of the Cinestar, there are 8 screws that go in here. Four that attach the plate to the gimbal and four that connect the plate with the pan servo. Without those in place, the pan servo would not be able to get proper traction and would thus spin quickly and then shut itself down automatically. Without physically being able to see that this was taking place, the spinning/loosing traction, I couldn’t see that the problem was within the physical build and not the electronics - which led to many many hours of trouble shooting down several rabbit holes that I took all the way to the end. And again - without these screws, I was unable to see that it wasn't connecting properly - the pan servo was definitely connecting, just not in the proper way.

    Lesson learned:
    1 - there’s always a benefit to having issues. I spent many many hours in the forums, reading manuals and adjusting settings on every component on the gimbal - the radians, servo’s, Graupner transmitter/receiver, etc. This was not time lost as I actually learned a ton about other issues people have as well as a ton about my gear and how it works - as well as feeling like I could trouble shoot a lot more now as it comes up.
    2 - before jumping into the electronics, first check all physical aspects - tighten screws, make sure screws are actually there, tighten belts, make sure belts are actually there - make sure that you actually have a gimbal in front of you - ha! Sounds funny but hey, you might be sitting in front of a small car which has significantly different wiring. Sorry - just trying to make myself feel a little better about such a simple issue.
    3 - while it seems like you shouldn’t shoot video of your issue to post in the forums because you don't see how it'll help, shoot video of your issue - just in case someone else see’s something simple like this. I actually shot video of my problem several times but never sent it in because I didn’t think someone would be able to ‘see’ my issue - I really felt like it was internal. But who knows, someone might have seen the lack of screws. A long shot, but still worth trying.

    Lastly - a huge thanks to Casey & Riley at Quadrocopter. They not only helped resolve the issue, but also helped with a few other wiring aspects I hadn't yet gotten to - awesome helpful guys indeed.

    Oh - and if anyone has any issues with their gimbal, please feel free to reach out as I now feel like I know that thing like no other. I'm also open to gimbal trouble shooting competitions, do they exist? Here's a quick glimpse of our first shoot out with the gimbal in proper working condition:


    Thanks, and may your troubles be smooth, enjoyable and rewarding.

    Glenn
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Glenn: Many thanks for posting the resolution and the sage advice it contains -- more to the point, the news that you learned so much from the issue and also that you resolved the issue! Way to go!

    Andy.
     
  12. Glenn McKenna

    Glenn McKenna New Member

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    Thanks Andy, appreciate all of your patient help and insight along the way. I keep hearing your voice from the Cinestar build video - 'just ask me how I know'. We say that regularly - how true indeed.
     

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