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May 16, 2016, 09:18 PM
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Question

Nano Rx Failsafe


Jim,

When a Nano-II goes into failsafe, what does it output?

I think the answer is a continuing stream of valid output on all six channels, each sending the USER value captured during the failsafe setup.

Is this correct?

Thanks,

Paul
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May 17, 2016, 01:09 AM
Xtreme Power Systems
It outputs what you have programmed it to do - either hold the last position or a preset failsafe position. The manual explains how the failsafe works and how to set it up.
May 17, 2016, 10:17 PM
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Ok. During a failsafe event the servos or flight controller (ppm from the Rx) still see valid signals, and do not even know that the Rx is in failsafe. Is this correct?

Thanks again,

Paul
May 17, 2016, 10:38 PM
Xtreme Power Systems
Not necessarily. One of the failsafe options (for each output) is to turn off the output when a failsafe occurs. If you do this, then a device like an auto-pilot or a flight controller can see a lack of PWM output as a failsafe condition.
May 18, 2016, 10:20 AM
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Ok, excellent - I forgot about that setting. Thanks Jim, Paul
Jan 02, 2017, 10:54 AM
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Jim,

First and foremost I wish you a happy and healthy new year.

With the Nano configured to output PPM, how many channels can be set for failsafe?

I observed that the first 6 channels indeed get set to the programmed values when a failsafe event occurs. I can configure channels 7 and 8 in the XDP, but they do not seem to be influenced by a failsafe event.

Please advise.

Thanks,

Paul
Last edited by FlyingW; Jan 02, 2017 at 10:59 AM.
Jan 02, 2017, 01:32 PM
Xtreme Power Systems
Good question, it may be that only the first 6 mapped channels are stored. Since PPM and Xtreme potocols were an afterthought, I am not sure. I will look when I get back in the office tomorrow.
Jan 02, 2017, 05:13 PM
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Ok, cool and thanks Jim.
Jan 03, 2017, 12:02 PM
Xtreme Power Systems
I took a look at the code and see that the Nano 1, 2, and 3 saves all 16 channels (whether 16 are used or not) in the failsafe memory. Those values are used for failsafe positions when a failsafe occurs. It does not matter what mode the output is (PWM servo pulse, PPM, or Xtreme) a single code routine handles all of them. Have you checked your channel mapping to see if you have those channels mapped?
Jan 03, 2017, 06:03 PM
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Here is the channel mapping I see with the Nano on the XDP. I cannot change channels 7 or above because the drop-downs are grayed out after channel 6.

I did see that all 16 are available in the Servo Positions screen.
Jan 03, 2017, 10:29 PM
Xtreme Power Systems
Yes, you can only change up to 6 output ports because the Nano only has 6 output ports. i guess this is a problem for PPM mode. Xtreme mode does output anything when there is a frame loss (that is handled by the device using the Xtreme protocol - like the X10+ or new X24). Maybe channel 7 and 8 would be output during a failsafe, since the channel output is sequential after output port 6. I am not sure, and I don't think there is any way to easily add channel mapping for non-existent output ports, even though you are in PPM mode. I will look into it.
Jan 04, 2017, 07:40 AM
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I take advantage of the capability that with the Nano outputting PPM, all channels 1-8 are controllable from the transmitter; and I already have a good work-around for the failsafe behavior on channels 7 and 8 so I am satisfied. I mostly wanted to understand what I was observing.

Thanks Jim, Paul
Last edited by FlyingW; Jan 04, 2017 at 07:46 AM.
Jan 08, 2017, 02:58 PM
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Update: I figured it out: I did not have channels 7 and 8 set to "user" in the receiver.

I have since set 7 and 8 to user and set the failsafe positions as per the instruction in the manual (first screenshot). All eight channels respond as programmed and channel 7 goes to about 2083us when in failsafe as seen in the second screenshot.

In the earlier post above I used a different Nano Rx to get the screenshots - that Rx had all channels set to user while the one in my aircraft only had channels 1 - 6 set to user and 7 and 8 to hold or off (I don't remember which one now). As a consequence of looking at the wrong sceeenshots I was unable to effectively troubleshoot.

All is well now. Sorry for the exercise - it was this user's error all along. Be well. Paul
Last edited by FlyingW; Jan 08, 2017 at 03:17 PM.
Jan 08, 2017, 03:56 PM
Xtreme Power Systems
Wow! Good find! I didn't think about the mode being something other than USER defined since that has been the default for awhile now.
Jan 09, 2017, 07:37 AM
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Yeah, about a year ago I set the failsafe mode on all eight channels to OFF for testing. When I set the mode back to USER I only set the first six channels with the idea of the six-channel Nano in mind, not thinking about the eight-channels available over the serial link.

I need to document my own setups for safety's sake!


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