Massive issues. Help ASAP. Lost a day of shooting and money!

Discussion in 'MōVI M10' started by Sam Donaghy Bell, Mar 4, 2014.

  1. Graydon Tranquilla

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    The only way to confirm your batteries are good is to determine the internal resistance of each battery. Most quality battery chargers provide that capability. Low internal resistance indicates that the battery chemistry is degraded. Some significantly degraded batteries will still charge to almost full volts. If batteries are confirmed good then....do the following:

    If the voltage does not drop at the batteries when connected to the loads but one or more of the loads is showing a significantly reduced voltage level across it... you have a high resistance connection somewhere between the battery and one of the loads. It's basic ohms law.... you have inadvertently created a voltage division circuit. http://www.solved-problems.com/circuits/circuits-articles/482/voltage-divider-voltage-division-rule/ ...... Also all loads must be wired in parallel to avoid voltage division.

    On the otherhand if the voltage read across the battery terminals suddenly drops while one or more loads is connected, then you one or more of the loads has become very low resistance and therefore is acting much like a short circuit.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    If I understand you correctly, Christopher, you're not using System -> Write Settings, or are you?

    Andy.
     
  3. Sam Donaghy Bell

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    I'm still here guys, Christopher is just asking and doing everything that I am. Thanks!
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sam: Are you using the System -> Write Settings after you have set up the gains?

    Here's what it says on page 04-P20 of the MoVI manual (I've emphasized the relevant sentence) -- please confirm that you are indeed doing the Write Settings:

    The Freefly Configuration GUI (Graphical User Interface) is the tool ​
    that allows you to adjust the software parameters of the MōVI. ​
    Changing these parameters will allow you to custom-tailor the MōVI’s ​
    behavior for particular shots, as well as complete the initial setup ​
    required for the MōVI. An important point to note is that you can
    change parameters in the GUI live with a tablet, but the changes will
    not be saved unless you write the configuration changes. This tells the
    MōVI to store the new settings and recall them upon power-up.

    Thanks
    Andy
     
  5. Christopher Aran

    Christopher Aran New Member

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    Correct, that is something I did not do. Seems like that might answer both Sam and my issue. Will test this out soon. Thanks for the info!
     
  6. Sam Donaghy Bell

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    N
    No this does not answer my issue unfortunately because I do this every single time I change gains.. Unless the gains would have jumped down but they were fine when I initially wrote them.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    OK. If you do a System -> Write Settings, and the settings are not preserved across a power off and power up, you need to open up a ticket with support@freeflysystems.com as I suspect there is an issue with the controller.

    Andy.
     
  8. Sam Donaghy Bell

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    An issue with the controller? Surely if the handset looses signal it just goes back to its majestic centre point? I can really do very little with out the epic on the rig but as you know I've been shooed away from set...
     
  9. Gary Haynes

    Gary Haynes Administrator
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    Chris you can save the settings in the Android version. once you get everything setup click on the System at the upper right side of the Android screen and then click on Write Settings.

    Similar for the Mac version.
     
    Christopher Aran likes this.
  10. Sam Donaghy Bell

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    So I just powered up the rig and handset. (No camera on). Checked the tablet to see what it read. I was really hoping to see the gains back at 10 but they weren't. Pan stiffness 118 Roll 47 and Tilt 45. These are the exact same numbers I had on the test day. Could my balance be THAT far out?

    Now correct me if I'm wrong.. If the gains are too high I will get oscillations, if the gains are too low the rig cant cope and will go limp??

    Those seem like pretty high gains to me? No?

    Thanks,

    Sam
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Right -- but the first problem I was addressing was the inability for the controller to preserve its gain settings across a power off -- if it couldn't do that, then there may be other issues with the controller that might explain the "go limp."

    It's hard to say whether your balance is correct or not -- the balance is (EDIT) essentially independent of the gain settings. There may be some interaction between the gain settings you need if the balance is a bit off, but really they're more or less independent.

    Certainly if the gains are too high you will see oscillation. But if the gains are too low, the MoVI will just be "lazy" in terms of its tracking. The "going limp" phenomenon suggests something other than the gains being wrong, at least in my experience.


    Hard to say -- the gains are specific to the camera, the lens, the way that you're holding the MoVI (two-handed or single handed from the top).

    Andy.
     
  12. Sam Donaghy Bell

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    If the balance was off enough would this cause the limpness?

    Sam
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    It certainly doesn't on my MoVI -- if I deliberately cause an imbalance by strapping a LiPo to the boom (as I did just now), the MoVI comes up, struggles to bring the Roll axis level, hums a bit, but doesn't give up and go limp.

    Andy.
     
  14. Sam Donaghy Bell

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    Then I really am stumped as to why it would go limp...? There seems to be problems but no problems that would cause the limpness... Not good...
     
  15. Ben Huddleston

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    I can weigh in with my experience: I used almost that exact setup recently for a 20-day shoot (Epic, Arri UltraPrime LDS lenses, even heavier than the regular Ultras, RTmotion FF setup, etc). I would experience that same MoVI-going-limp from time to time and what I determined was that it is a compound problem.

    1. When your camera package is approaching the upper weight limit, perfect balance is imperative. Get it PERFECT. My setup was 11.99lbs for a 12lb rated gimbal.
    2. The Freefly LiPo batteries are the culprit. They're fine when fully charged and the lipo is a healthy one, but at 50%, if I were to aggressively move the MoVI, it would go limp as you experienced. I finally figured that if I changed the lipo when the 3 lights went to 2, it would eliminate that problem completely, provided the balance was good.

    Unexpected flaccidness is an unwelcome state. Sorry you lost out on the job. Get extra lipo batteries and swap em out often.
     
  16. Sam Donaghy Bell

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    Really...? 50%... Not great. I'm good with every balance but my pan balance needs work. Everytime I think get it and tighten the screw and try it again it's off. Frustrating. This is a great help Ben thank you.
     
  17. Kurt Wallrath

    Kurt Wallrath Member

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    Ben's advice is perfect when your rig weights in at more than 10lbs. I've gotten into a habit of changing LiPo batteries on the MoVI shortly after the first LED battery indicator goes out on the 3 LED battery indicator on the back of the MoVI. Also, buy a LiPo battery voltage checker to make sure none of the cells drop below 3.4 volts.

    After you've balanced the MoVI and set the strength (gains) of each motor, check the motor chart on the GUI. (it's under the "chart" tab on an Android tablet). Once you're on the "chart" tab, click on "motors" so you can see how much strain is on each motor. I usually am happy with the initial balance being between -10% and 10% (a positive value is one direction from the MoVI's initial position and a negative value is the other direction) with 0% strain being the optimum number. If you find your initial balance higher than 10% or lower than -10%, I find it helpful to do a quick rebalance for the motor that's straining. I'm neurotic so if I'm a tech, I keep my eye on that chart to see if the motor are straining too much.

    I was recently on a shoot where we had the MoVI tilted down for the shot and all of a sudden, the pan motor gave out and the camera swung around 180 degrees. I checked the battery, which was still at 15.6 volts so I strengthened the pan motor. Problem solved.

    One more bit of advice, I haven't had much luck with aftermarket batteries. I've had limp MoVI problems using aftermarket batteries, especially anything less than 4 cells.
     
  18. Sam Donaghy Bell

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    Ben's advice does seem like the winner although I've lost 3 days of shooting now because of a battery that can't go below 50%... Annoying to say the least..

    When you say,

    "I was recently on a shoot where we had the MoVI tilted down for the shot and all of a sudden, the pan motor gave out and the camera swung around 180 degrees."

    Did just the pan motor die or did everything? Reason I ask is because all of my motors die not just a single one.

    I'll try and test this but it's not really something I can do without a camera.. =/

    I'm also a little concerned about the battery issue not powering up the camera from the freefly vlock adapter but will power the accessories as I mentioned in issue 2. Any thoughts on that Kurt and Ben?


    Thanks,


    Sam
     
  19. Sam Donaghy Bell

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    Ben,

    In regards to this 50% business what would you think about these batteries with nearly double the capacity? I'm very tempted.

    http://www.brchobbies.co.uk/catalog/product_info.php?cPath=82_84&products_id=1540


    Sam
     

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