Failsafe

Thought i understood how fail safe worked but apparently not..I set it up on my reptile quad with devo1202 rx on the ch5 which is the flight mode switch , i set the fail safe value the same as the switch value when RTL is selected and it works. I tested it out both on mission planner and in flight by turning off the tx ....I tried to set it up on 2 of my planes which have dsm2 rx's on the elevator channel so if signal is lost it will give 3/4 elevator so not to nose in hard but it wont work, when i turn off the tx the servos just stay neutral and the throttle stops...any idea what's going on anybody?

Hi,

which brand and type of DSM receiver are you trying to teach failsafe positions of channels? You sould check in the receivers manual for instructions on how to set failsafe positions.

If I remember correct, on my Spektrum AR6210 receivers (they use DSMX protocol, but this shouldn't matter for setting failsafe) the failsafe positions are stored during the bind process.
The steps were the following:
Plug in the bind plug,
power on the receiver,
power on your transmitter (it can be powered earlier, but it should not be in bind mode),
bring the sticks on the transmitter in your preferred failsafe positions and enter bind mode on the transmitter.
The set should bind, the stick positions given at binding start should be stored as failsafe positions.
When the set is bound, unplug the bindplug from the receiver and power it down.
Finished, proceed with normal operation.

As mentioned, the process could be different on other brands and types of receiver.

I hope this helps a little.

Best regards
Max

actually trying it on 2 different receivers one is a AR6200 and the other is the orange 6ch rx the earlier version ...i tried the ways you mentioned and the manual on both says nothing about failsafe other then it will cut throttle ..On my Lemon and Orange 9ch it works using the rx setup procedure

You are right, I just tried it with an AR6210 and a Devo F12E, it did not work...
I just read the manual for the receiver and the failsafe instructions are described as mentioned above.
I will dig out a DX8, test it and give feedback.

The AR6200 has what Spektrum calls "Smart Failsafe" and from what i read the older orange rx i have has the same thing i just don't understand why Failsafe works with Devo receivers and not DSM receivers..

I have a spare Devo rx802 laying on my work bench i'll bind it up and try it to see if it works with it ..I am trying this on my 12s but i don't think would matter...

Tested, no luck.
You are right, the AR6200 and also the AR6210 seem to only support "smart failsafe" --> all channels besides throttle centered, throttle to low position.
I checked the manual of the DX8 and there it is mentioned how to set "custom" failsafe positions but this is meant in combination with the AR8000 receiver which was in the bundle...

I tried this method with the AR6210 and had no success.
There seems to be no "custom failsafe" on the AR6200.
What I´ve in memory had to be with the AR8000 but I don´t have one of these arround anymore.

Sorry for misleading you.

Edit:
I tried it on a Sektrum DX8, a Devo F12E and also a Devo 12S. Made no difference.

Tried it on the devo rx802 and it works perfect i set 100% elevator to failsafe and powered off tx and the servo went to 100%...Perhaps i will swap out the AR6200 for the rx802..

You are looking for "preset failsafe" receivers.

Normal receivers do support only "hold last command" on all other channels besides THR port (failsafe value as on bind process; you usually want to bind with -100% throttle value for electrics).

No, AR6210 or AR600 do not support "preset failsafe".
Yes, AR8000 and others do support preset.

Yea I was hoping that the tx would send a signal burst ect to the rx to trigger failsafe when it detected very low connection strength ...Which would make preset failsafe work on any rx but i guess we can't have it all..

One more thing you can try if the above posted procedures are not working: go in on Devo to the throttle Channel and turn the lower value all the way down (make sure the channels not reversed, if you have it reversed for whatever reason that's fine but you'll need to raise the upper limit instead of lower the lower limit).

That way you're outputting the lowest possible pwm value that will be outside of the flight controllers accepted parameters and that is what will actually trigger your Fail-Safe. I turn mine down to -250 @150% for binding. Don't forget to turn it back up before you fly, you only want to do this while your binding!


If you just still can't get it to trigger the other thing you can do is whatever Channel you're using for flight modes, on APM I use Channel 5, set that channel to be the value that is return to home mode. So for example I have RTH as mode 5 so I would set my channel 5 to whatever mix of switches you need to be in mode 5 and it won't actually have to pick up the signal loss.

As noted, DSM Rx's tend to either set FailSafe in some Rx-specific way, or not have it at all. My preference is FrSky, which has a dedicated button on the Rx that you push to record Failsafe values, so they're nearly impossible to change accidentally.

Devo is unique, and probably the easiest. You set the values on the Tx, and it sends them to the Rx. That's what Deviation's "Failsafe" setting does. I don't think it works on any protocol but the Walkera ones, but I don't use every protocol deviation supports. In theory, we could make DSM send the failsafe values at the right time during binding instead of stick positions, but that wouldn't work on all Tx's, so it's not clear that doing it would be worth the confusion it would create.

Good idea on the APM setup but unfortunitally it wont work on my planes i want fail safe to not only shut off throttle (which is currently does) but also set 1/2 to 3/4 up elevator so the plane will not nose in but kind of slowly glide down....but the only way i can get it is to use a different rx other then the ones i am using...my 9ch orange and dsmx lemon works perfect the way i want but they allow failsafe to be set up to the operators desire...

FDR wrote:

mwm wrote: ...
In theory, we could make DSM send the failsafe values at the right time during binding instead of stick positions, but that wouldn't work on all Tx's, so it's not clear that doing it would be worth the confusion it would create.

What do you mean on that it wouldn't work on all TX's?
I would like to have it that way, and if I remember right, there is an other deviation supported protocol, which uses those values too.

Sorry, I mean it wouldn't work on all Rx's! So if someone sees a video/blog/tutorial showing how to set up a DSM Rx with failsafe, they may well wind up wondering why it wouldn't work on theirs.

Hmm. Apparently Indigo agreed with you. Checking the source for that "other" protocol, it seems like DSM sends the failsafe value during binding if failsafe is enabled for that channel. I just tested it on an OrangeRx R820, and sure enough it works. So you get your wish.

However, it won't work for all Rx's. I know OrangeRx does this, but some of the clones have a button (though using that will now be easier, since you can set failsafe values in the model setup instead of on the sticks). IIUC, it's also different from the Walkera Rx's, which set the failsafe values whenever they connect to a Tx, not just at bind time. Now someone needs to document this in the manual!

FrSkyX seems to use it the value as well.

So if i set failsafe on a channel and rebind my rx it will work if the rx supports it? So there's no way to get it to work on all rx's it seems..

Yup, it probably won't work for all Rx's. Hopefully, the ones that don't support it or use buttons are all obsolete, but who knows?

And that was the reason I was never interested in doing this. But Indigo did a lot of DSM work, and apparently decided it was worth while.