Aner

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What if no MAG?
« on: April 01, 2016, 06:32:58 pm »
Have bought a Ublox M8N GPS for my Revo. It says "with compass " and it only has four cables which means the compass it not connected/used but likely inside the shell... But the question is what happens if only GPS is installed and not the MAG is used, which will be the case for me because I'm out of spare ports? I mean, there must be a great number of users flying without the MAG (if one reads about the subject so to say...). Will it work with position hold for instance bur with som reduced accuracy? Furthermore, do I have to do all the calibration procedure eve though there is no MAG used?


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Aner

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Re: What if no MAG?
« Reply #1 on: April 01, 2016, 06:58:31 pm »
Guess i found the answer to my own question:

The ABC Steps of Autonomous Flight on Multicopters
https://forum.librepilot.org/index.php?topic=15
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hwh

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Re: What if no MAG?
« Reply #2 on: April 01, 2016, 06:59:47 pm »
If you have a revo you have a mag sensor on it and need to do the mag calibration.

The reason for preferring an external mag sensor is that it's hard to get the one on the revo to work correctly because it's usually mounted inside the quad in the magnetic field generated by the power wires.  If you search there are threads talking about twisting the wires to minimize the power wire generated field's effect on the sensor.

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Re: What if no MAG?
« Reply #3 on: April 01, 2016, 08:09:52 pm »
Oh, that's really good news for me man. My Revo i mounted on the top of my tricopter  with the ecs on the arms under the motors. So, the interference should be less. Ill give it a try.
So, at this moment the revo has already installed/chosen its internal mag i guess through the setup wizard procedure ? Then its only the calibration left then... Or do one need todo anything additional setings for the MAG in particular in the system tab.

Thanx for the reply.
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hwh

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Re: What if no MAG?
« Reply #4 on: April 01, 2016, 08:37:28 pm »
It won't use the mag until you go to a gps flight mode but there's nothing else you have to do but calibrate it.

The wiki article https://librepilot.atlassian.net/wiki/display/LPDOC/Sensor+calibration tells about calibrating all the sensors including the mag one.

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Re: What if no MAG?
« Reply #5 on: April 01, 2016, 10:33:06 pm »
Ok. The reason I'm asking is because I haven't yet specified any other flight mode than just "stabilized " for flight mode 1 and 2. Thats because I wanted to test the tricopter with the new revo board without any assisted flightmode problems yet...
After finished calibration of everything except temp sensor, the osd now warns for "mag critical. "Just stabilized" flight mode doesn't use mag, so this shouldn't show up and cause any problem. Next problem is that the aircraft is stone dead on outputs... Not even the tail servo for yaw is responding. Nor less arming motors. On input tab everything is fine and I can also test outputs though the output tab section. But no output from tx signals. Strange.
It has happened once before, and that was before i even had bought a gps module. It just locked everything up after doing som settings for the battery/current sensor for the osd (minimosd). Same thing. All outputs just stopped working. Had to reset the board. I guess I will do it this time again:/ 

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Re: What if no MAG?
« Reply #6 on: April 01, 2016, 10:58:19 pm »
You needn't have a GPS mode active or even assigned to a switch for the MAG to become active.  Simply setting stabilization mode to GNS13 is all it takes.  So if you've selected that mode in the stabilization screen, you'll need to do the MAG calibration successfully to get that alarm to go away.

Highspeed

f5soh

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Re: What if no MAG?
« Reply #7 on: April 01, 2016, 11:03:16 pm »
Quote
the osd now warns for "mag critical. "Just stabilized" flight mode doesn't use mag, so this shouldn't show up and cause any problem

If you switch to Complementary (basic) you should reboot board so Mag should not display Mag alarm anymore in Osd. (Grey Mag in SystemHealth)
If you are using INS13GPS and a stabilized only (not assisted) flightmode, your attitude estimation still use the Mag.

Re: What if no MAG?
« Reply #8 on: April 01, 2016, 11:06:08 pm »
Quote
the osd now warns for "mag critical. "Just stabilized" flight mode doesn't use mag, so this shouldn't show up and cause any problem

If you switch to Complementary (basic) you should reboot board so Mag should not display Mag alarm anymore in Osd. (Grey Mag in SystemHealth)
If you are using INS13GPS and a stabilized only (not assisted) flightmode, your attitude estimation still use the Mag.

Ha! I beat you to it!  :)  I did typo the mode wrong (I meant INS13 instead of GNS13) but we both came to the same conclusion.

Highspeed

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Re: What if no MAG?
« Reply #9 on: April 02, 2016, 08:31:21 am »
You needn't have a GPS mode active or even assigned to a switch for the MAG to become active.  Simply setting stabilization mode to GNS13 is all it takes.  So if you've selected that mode in the stabilization screen, you'll need to do the MAG calibration successfully to get that alarm to go away.

Highspeed

Hi
Yepp, i had my settings for INS13GPS. Did the calibration successfully, but thats when the alarm for mag started showing up (after calibration). I assumed one had to use INS13GPS to get it work with GPS? Anyway, it's strange that it locked all the outputs, even the tail servo. Even without any GPS assisted  mode activated.
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