MK Failsafe testing and switch activation

Discussion in 'Electronics' started by Cam Batten, Jan 8, 2015.

  1. Cam Batten

    Cam Batten Member

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    Two things I'm trying to clear up regarding failsafe on the MK (latest hardware / software latest, but not the beta)

    Testing failsafe - How should the aircraft react in the following circumstance.

    Props off, bench testing, activate motors, switch off transmitter.

    Should the motors continue spinning, or will they shut off automatically, because the aircraft believes it is home?
    I'm hearing the beep, and seeing the Error 7 via MKTools, however the props spin down, which has me concerned it isn't functioning. The GPX file shows that GPS home was activated.

    Second point - Is it possible to program a switch on the TX to simulate signal loss? I read you could do it, but cannot see how. I'm flying with the Jeti DS-16, dual receivers on the aircraft, both with failsafe disabled. I would ultimately like to use a two position switch to cut TX transmission, and induce the failsafe on the MK. Any clues?

    Cheers,

    Cam
     
  2. Holger Göhr

    Holger Göhr New Member

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    Yes you can simulate a receiver failure with your Rx.
    It's the fail safe channel in Mk tool.
    Change that to the poti you require and you are done. I'd use a spring loaded 2 way switch.
     
  3. Cam Batten

    Cam Batten Member

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    Perfect, makes much more sense, I had wondered about that poti assignment. Thanks Holger
     
  4. Cam Batten

    Cam Batten Member

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    A few more questions regarding failsafe. I have a spring loaded switch activating failsafe, when I release the switch, I have to re-arm the MK before I can start the motors again (while on the bench). Is this normal?

    I should add, while on the bench with motors spinning, I engage failsafe, the motors cease to spin. Again, is this normal? I am hearing the beep and see the red light for failsafe, but I'm concerned that if I try this in the air, the aircraft will fall.. If not and the failsafe is working, am I correct in assuming that when I disengage failsafe, the throttle/mode etc will immediately resume to their correct position, and not be impaired by the normal startup procedures such as arming and motor stop start switch.
     
  5. Ozkan Erden

    Ozkan Erden Distributor

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    Just a reminder: You also need to change a setting on Graupner TX for MK failsafe work properly:


     
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  6. Cam Batten

    Cam Batten Member

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    Ozkan, I am using Jeti system, and have disabled failsafe on both of my receivers. (running dual path with an rsat2)
     
  7. Cam Batten

    Cam Batten Member

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    For anyone with this same predicament and apprehension for turning off your transmitter, here's how I went about confirming failsafe would work.

    First, assign a trigger switch via MKTools to initiate FS.

    Check for error RC Signal Lost via MKTools, when activated.

    Keep the props off, take the aircraft to an open space and start the aircraft as per normal. Keeping the motors spinning (I kept them about 50%) pick up the aircraft and walk it at least 50m away from your arming point.

    Activate FS via the trigger switch, you should observe the motors continue to work. Now release the trigger switch, then after a moment, switch off your TX and observe the same behaviour as previously mentioned. Now switch on TX, making sure you can resume control immediately by raising the throttle stick.

    Next, check your logs from the sudo-flight, and make sure you see the appropriate notes - failsafe active, GPS and coming home active etc.

    Finally, strap the props on, and go try it again, making sure you have set your descent rate as per the wiki. I tested mine this morning and made sure to have a camera pointed at the aircraft in case anything went amiss. Probably a good idea to strap on a gopro or similar to record onboard sound and vision.
     
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  8. Derek Cooper

    Derek Cooper Active Member

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    Can you point to a configuration doc on dual receiver setup in redundant mode on the drone? We are running a redundant BL with two FCs.

    We are making the switch from Graupner to Jeti.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Interesting to hear you're switching, Derek. Are you finding issues with the "new" Graupner/JR equipment? Just curious as to what's causing you to switch.

    Andy
     
  10. Derek Cooper

    Derek Cooper Active Member

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    A couple things:

    1) The Graupner radios are nice, just not the best build quality. We were looking at ways to attach extra equipment to the MZ-24, like a monitor for the pilot, but couldn't find any secure mount points. Lotsa plastic.

    2) We do notice shorter transmission distances than anticipated. On a few flights yesterday with LOS, we were dropping to 30% receiver strength. Both the Paralinx and telemetry on the Movi Controller with our booster were performing just fine.

    3) We are super intrigued by the dual path dual receiver option with the Jeti on the drone. Was talking with Jeti this morning and we can mount the two RX units on either side of the drone, so one is always completely exposed to the TX. Nice. Also gets around the single-point-of-failure model of having just the one RX on the current drone.

    4) The Graupner docs are certainly lacking. We also talked to them directly regarding the teacher / student linking between the two radios (you'll remember that post here) and didn't get a clear answer. We were told they'd call us back but never heard anything. Jeti support seems great, docs are clear, website is clean.

    So we have a Jeti radio and two receivers arriving this week for testing. If we like what we see, we'll move over to Jeti and put up all the Graupner stuff on eBay.

    Sounds like a plan?

    If you know how to get the two RX units wired up in a redundant configuration on our redundant setup, I'm all ears...
     
  11. Derek Cooper

    Derek Cooper Active Member

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  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    This may also be relevant: -- but I'm not entirely sure as it deals with disabling telemetry on a second Graupner HoTT Rx so they don't contend with each other.

    Andy.
     
  14. Dave King

    Dave King Well-Known Member

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    Derek are you talking about signal strength or signal quality? One signal is telemetry strength and one is TX strength. Telemetry strength is always lower than TX signal strength. I had all sorts of issues with my Graupner radios earlier this year and found my problem to be the TX. For whatever reason it simply just would loose signal quality after it was away 25 meters. Replaced the radio and everything is good.

    Are you using 2 graupner radios or a Graupner and a specktrum for the Movi? There's a way to trick the Graupner radios so that the 2nd receiver does not send telemetry back. It works like a charm let me know if you need help with this.
     
  15. Derek Cooper

    Derek Cooper Active Member

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  16. Cam Batten

    Cam Batten Member

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  17. Derek Cooper

    Derek Cooper Active Member

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  18. Derek Cooper

    Derek Cooper Active Member

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    I note the RSAT2 is not certified for use in Canada and the US, so we can't use it. Transport Canada would have a fit if we put it on our drones. Good luck getting flight permits! :)
     
  19. Cam Batten

    Cam Batten Member

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    Ah, I'm in Australia, where I'm unaware of any restrictions for the RSAT2. I haven't ever tried to use a second 'R' series, however it should still be possible.
     
  20. Derek Cooper

    Derek Cooper Active Member

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    Cam - what electronics are you running on your drone, Mikrokopter? Curious if failsafe works fine with your RSAT2 RX.
     

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