Hi everyone
I'm using apm 2.5 firmware 3.1.4 on my hexa. It had been "put away" for the last year since I encountered a problem with it that was never answered.
The problem was it would go into failsafe at random. I only fly in alt hold or stabilize, so these are the only two modes I experienced this with, so I can't say if it occurs in other modes.
Looking at the logs to investigate, I could see that my throttle in would drop to zero while flying, and of course this triggered failsafe. At the time, I suspected a bug in the code or my radio tx/rx or inputs. I put the APM away till I figured this out.
The radio was a JR8103 and its 9 channel rx.
Presently, I've pulled the APM2.5 out of the drawer since now the new and improved firmware is out.
It is running 3.1.4 as stated. Also, a new radio and rx, Jeti dc-16.
It has been running fine for a number of flights so far until today. I had taken off, flying maybe a few meters altitude and within ten meters from myself, it started climbing with no response to throttle.
I immediately switched to alt hold and back to stabilize when I regained throttle response. I continued flying without any further problem.
Looking at the log for this flight brought back memories from last year. The same thing. Throttle In
dropped to zero, triggering failsafe.
Well now I know, it is not the radio/rx. And I have tried to induce a failure to the apm inputs by shaking up the wires. No luck.
Hopefully I can get some input here. Please let me know if anyone would be so kind to check out this log. Am I doing something wrong??
Cheers, Steve
Replies
Chris, could this have anything to do with the PPM Encoder? I was using a Futaba T8fg with the bundled 8ch rx. Kept twitching in flight. Then I came across the info that Futaba 8ch rx had problems with the PPM Encoder. I'm making a wild guess, and the problem's occurring with two different radio setups, but could a similar thing be happening here?
Perhaps. Are you using it in PPM mode (with the jumper on RC in 2&3)? The APM 2.5 is an older board that hasn't been made for a couple years and came out before the newer Futabas with that compressed 8-ch pulsetrain. If so, the solution would be to upgrade to APM 2.6 or Pixhawk. (You can also update the PPM firmware, but it's a slightly complicated process)
It looks the FS is generated due to a radio error, see below.
You said you did have the same issue for both radios.
Do you have the logs for both radios in order to compare the errors?
What other electronics do you have which could interfere your rx/tx? Any GoPro with wifi? Try to keep (disable) the minim electronics and see the result
Hi there
Was checking my post from last year to find the log using the other radio setup. For some reason it is no longer there, so I do not have that to compare with what is happening now since my computer was reformatted.
However, if you can take my word for it, what is happening now if you look at throttle in, you will see that it drops to zero quickly, comes back up and goes back down again. This was not my input, and it is what happened when using my other radio last year. I remember it specifically, but I certainly do understand the need for backup data which unfortunately I do not have.
From my point of view, I have to rule out the radio, since two have been used, and both work flawlessly with my other systems. Intermittent wiring- not likely, since graphically it is the same pattern on every occurrence, and I have tried to induce failure shaking up connections. APM code-possible, but not likely since there does not seem to be many discussions on this. APM hardware-most probable cause, the only thing left.
I'm hoping for more info, but I also realize user error is top of the list in most experienced people's minds.
For now, I have to place my APM back in the drawer.
Cheers and thanks for your reply,
Steve
And you're not using a GoPro with the Wifi turned on, or any other RF emitter that could be causing this interference? There have been no other reports of this, as far as I know, so it seems specific to your setup.
One thing that might be worth doing is upgrading your firmware (you're a couple versions behind). 3.2 RC2 is in the beta software link on MP and APM Planner.
Also, I assume you've got your APM mounted on vibration-damping foam? That isn't related to your radio loss, but it's important with newer code regardless.
Hi Chris
No, I never use wifi on the gopro. I do use 5.8 ghz boscam tx at 600mw but it also happens with it off. Problem too, is it happens so rarely, I can probably fly for 50 flights before it happens again. Don't forget this has occurred on 72mhz system as well and I immediately suspected interference or radio glitch. But after using another radio at 2.4 ghz with the same thing happening, I have no choice but to suspect the APM.
The throttle in channel drops to zero suddenly, while all other input channels are what I am inputting.
I hope I am reading the log correctly.
Also, Brit Davis has a log that shows something similar to mine, except I didn't get the batt-1 error.
I attached his log.
My vibrations are well within the recommended levels with foam. XYZ accel all +/-1.
And I will take your advice and try the new firmware. Thanks Chris
201402220805Failsafe.log
Sorry i didnt check the logs but a throttle of really zero sounds like perhaps the wiring between the rx and apm jumps about and cuts the connection. Then perhaps due to vibrations it reconnects.
Replace the wiring or if you can try switching to the muxed mode where everything goes over one wire rather individual wires one for each channel.
Hello
Yes I thought of the wiring and determined that is not the problem.
PPM mode sounds like a good thing to try.
What I am worried about switching to PPM mode, RC in 2&3 have to be shorted. RC in 3
is the throttle input in the standard mode, and that is where there could very well be a problem. Not sure what would happen in flight in that case.
With all that said, I think it is best that I finally lay this board to rest, .....sniff,sniff, tear
Thanks to you all for your inputs, I really appreciate it,
Steve
Sorry, forgot to answer your questions.
It happens very randomly and not very often, both with and without any other devices operating.
Cheers, Steve