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P2: Connecting a servo to the F2 Naza problem

Discussion in 'Phantom 2 Help' started by paturoa, Apr 28, 2015.

  1. paturoa

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    Hi, new to this forum.

    My dad has purchased a P2 and I've ended up being the tech help. What he wants to do is use the P2 to drag out a fishing line with multiple hooks beyond the surf break and drop it, then return to home point.

    So he's bought a Tower Pro SG90 micro servo to actuate a hook system. The guy he bought if off wired a 3 pin lead from F2 on the Naza. I went into the P2 App and calibrated X1 and it all seems to work properly.

    Next I checked the pins from the Naza and pos 5v is centre with signal and earth either side. Next is I double checked the servo pins and specs and that all looked OK.

    So I plugged it together and turned on as per normal. Moving the gimbal tilt lever on the back of the controller moves the servo but here is where the problem(s?) are.

    • The servo is supposed to rotate 180 degrees but only gets about 90.
    • It doesn't move proportionally to the lever. For a lot of the range nothing and then some jumps.
    • It will often vibrate when in position.
    So I got out the trusty meter and double checked the pin outs, all good as spec. Then I noticed that the servo was warm. So monitored the current on the 5v supply and it would pull about 700mA max when it was vibrating and bugger all when not. 700mA is way too much for a no load situation on a micro servo.

    So after a bunch of searches tried various settings for the advanced-> gimbal -> gimbal config settings and that made no difference. Then spent several hours googling and reading everything. There is one other thing I've not tried and that is to use a ferrite ring but I don't think that is the issue.

    Anyone else got a 3rd party servo working properly? Am I using the correct wiring etc??

    Cheers Brian

    edit: I'm currently suspecting that the prob is the servo itself and will try another one tomorrow (if I can find a cheap one)
     
    #1 paturoa, Apr 28, 2015
    Last edited: Apr 28, 2015
    IflyinWY likes this.
  2. IflyinWY

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    Hey Brian, it sounds as though you have found your way into the NAZA assistant software. Is that correct?

    Are you putting enough of a weight load on the servo?
    We need you to resolve this problem very soon. I can see the fish jumping 3 to 400 feet offshore.
     
  3. paturoa

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    I've been using the Phantom 2 assistant software. I'll have a look for NAZA specific. Weight on the servo doesn't make any difference to how the servo is behaving.
     
  4. paturoa

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    Tried using the NAZA software but it wont connect. The Phantom software still works.
     
  5. IflyinWY

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    Yep, I guess you guys do it different with the P2.

    I'm eager to know which servo ends up working for you.

    Thanks
     
  6. paturoa

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    I'll post up what happens. Might take a few days though.
     
  7. CityZen

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    Several possibilities:
    - you might have a bad servo
    - you may just be trying to drive the servo past its end point
    - you may need to calibrate X1 using the RC Assistant - plug the RC into the computer. If there isn't a USB port on the bottom of it, it's inside. Remove 4 screws, lift the back a bit, then slide it down. Of course, you'll have to find a way to run the USB cable out of the RC since you probably have to close it again to move the X1 lever.
    - do you see different behavior when selecting "upgraded" or "basic" remote?
     
  8. paturoa

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    Thanks for the ideas people keep them coming.
    • Just went and bought a new servo and tried that, different brand, exactly the same issues = not servo.
    • I previously marked the end points on the servo by manually rotating both of them, it doesn't drive to either limit = not end point.
    • I've previously calibrated X1 into my PC from the USB port and it swings +- 1000 properly. I can also see it (on the app) swinging proportionately as I move the lever backwards and forwards on the controller. = not that
    • I've also tried both settings for the remote ie basic and upgrade and no difference between them at all = not that.
    My next step is to drag out my ancient oscilloscope from the loft and have a look at the time pulses / duty cycle that the P2 is putting out.

    onwards.....
     
  9. N017RW

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    Maybe the channel's PWM range is somehow restricted (like dual-rate) since the gimbal was not intended to move more than 90deg.???
     
  10. CityZen

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    On the P2 Assistant, under the Advanced/Gimbal screen, you can change the settings for the F2 channel output limits.
     
  11. paturoa

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    Could be..
     
  12. paturoa

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    Yeah, I've played with those settings but they don't seem to make much difference.
     
  13. paturoa

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    Well might have made an interesting discovery, but have to go out soon to pick up one of the spawn from basketball....

    Both my meter and as far as I can tell my oscilloscope rekon that the output freq of the port is 200 Hz. The spec for the servo says it is 50Hz. Hmmm.

    The P2 assistant tool doesn't let me change the freq. However the Naza-M V2 assistant (which doesn't connect to the external port on the P2) has a selector to change the frequency.

    Any suggestions from here?
     
  14. CityZen

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    When I run P2 Assistant (version 3.4), I can change the output freq if "Gimbal Switch" is on.
     
  15. N017RW

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    Maybe this [200Hz] is a 'special' Phantom thing, 'cause the Naza-M v2 manual (v1.26 - page 5) states the outputs are 400Hz refresh.
     
  16. paturoa

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    Nice info. Just checked and I downloaded v3.8 which doesn't have that setting. I'll have a look around to see if I can find 3.4
     
  17. paturoa

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    The DJI site had v 3.6 and that is identical to 3.8 and does not let me change the freq. More looking required.
     
  18. paturoa

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    I managed to download 3.4 (by copying the link from DJI's download page and changing the target). When I installed it still had the same gimbal change options as the later version with no frequency option. So I uninstalled the later versions. Still couldn''t find it. I then went back to 3.2 and ditto.

    Can you do a screen shot of where in the app you see the freq setting please.

    edit: even managed to find an ancient 2.20 version which wouldn't run.
    edit 2: So messaged DJI support - will see what they have to say on the topic
     
    #18 paturoa, Apr 29, 2015
    Last edited: Apr 29, 2015
  19. CityZen

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    Okay, so I sort of see what's going on. The Phantom 2 Vision Assistant tries to determine which Phantom you've got plugged in, and it will only show the tabs that it thinks is appropriate for that model. I only see the Advanced/Gimbal tab when I plug in a P2V. When I plug in a P2V+, it doesn't show. Odd thing is, the P2V I used was really a P2V+ with all the Plus stuff removed and a P2V camera stuck on. When I unplug the camera, it still thinks it's a P2V. (It shows the model name in the title of the window.) When I run the Assistant without plugging in anything, I see a different Advanced/Gimbal tab.

    Here's a thread that shows some hope for tackling this: http://www.phantompilots.com/threads/using-the-7th-channel-patch-will-disable-gimbal-tab.11034/
     
  20. paturoa

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    Thanks