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Mar 10, 2015, 09:02 PM
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Quote:
Originally Posted by jdennings
Absolutely.

I've started looking back at my logs, just looked at 20 of them for now, with flights > 15 minutes. Here's what I've found so far. Most have INAVerr > 0, with InavErr varying from 1 to 40, straight horizontal line suggesting the error happens before flying or right at the beginning. 19 logs out of 20.

*BUT* ...

I've got one scary one. Inaverr starts at 0, then goes to 40 about 30 seconds in the flight. Stays there for 5 minutes or so, then ramps up again to 100 right during the flight.

This was a while back and I don't remember the flight, except I know I had no issue. Go figure. This is quite disturbing.



I'd fall in that category. Great pos hold yet some errors.
Going to look into this more carefully from now on, + got lots more logs to look at.
I looked at many logs from the Y6B that had several >0 INAVErr but no indication of flight problems in missions.

Ha! My INAVErr is 255 start to finish with the current setup using the M8N, so I'd be in the category of "I'd be concerned". Of what I don't know, but those that say they've been using them without issues either aren't pegging at 255 or are playing Russian Roulette.

I looked at earlier logs with the 3DR GPS and it averages around 30 or so. Some have 0.

CSGShop advertised the M8N as the greatest thing since sliced bread and probably sold a large number of units. As they say Caveat Emptor.

What I'd like to see now is if and how people are making them work without high INAVErr. If not, then I'll just go back to the 3DR unit and live with not flying on some days.
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Mar 10, 2015, 09:09 PM
Registered User
Quote:
Originally Posted by jdennings
fwiw (not much), here's a flight I just did with M8 GPS (and 8XR receiver). Great position hold precision, etc ... no issue.

What bugs me in this case is that with InavErr maxed out at 255 from the get go, I have no way of knowing whether there were some misses in flight ... But if there were, it sure was not an issue ...

Attachment 7657182

Attachment 7657267
That's the most frustrating part; flying and everything seemingly works fine.

One mission however I do recall I had the speed set at 12 m/s, but the logs showed it it was only moving at 3-4. Funny how after thinking about this there's a bogeyman behind every corner.

So what are you going to do? Continue using the M8N or switch back to the LEA-6H? What really frosted my cookies was CSGShop's knee jerk response it was a Pixhawk issue.
Mar 11, 2015, 04:57 AM
Registered User
Had a very scary experience today.
I've built a Sky-Hero X8 with a pixhawk F/C. After endless hours setting it up and doing "flights" with no props, and getting lots of pre-arm warnings from gps hdop and bad gyro healths but not finding out what was causing them, I attached props and gave it a maiden flight. Obviously, no pre-arm warnings came up so after repeatedly making sure the RTL showed when I switched it on I decided that now was a good time to try to hover. She rose gently and proceeded to gently fly away. This was in stabilise mode. I had no throttle control whatsoever. This never happened on my "Grounded flights". After it got about 50 meters away I hit the RTL switch as a last resort. It started to come back, thank God. The landing was pretty rough. It took three goes at landing, each time it would bounce back in the air after descending to rapidly. Finally landed and switched itself off. Don't want to go through that again. Anybody have any ideas what could have caused loss of throttle control?
Mar 11, 2015, 05:05 AM
Registered User
Av8Chuck's Avatar
I'm new to this controller but my first PixHawk did the same thing. I called 3DR support and although it took a bit longer for them to reach the conclusion than I might have liked, when things don't work right I'm not sure anyone could ever fix it fast enough, but after several tests they concluded that I had a hardware failure.

I started getting bad gyro health warnings, when I did and was hooked up to the GCS the artificial horizon would slowly start to roll.
Mar 11, 2015, 05:09 AM
Registered User
What do the logs say?
Mar 11, 2015, 05:16 AM
Registered User
Quote:
Originally Posted by mackar
What do the logs say?
I've sent a copy to 3DR as I wouldn't know what I was looking at. When I initially plugged her in, the artificial horizon had rolled way off to the left. It took numerous unplugging and plugging in's before it came right and level. Bad Gyro health popped up a couple of times as well while doing this.
Mar 11, 2015, 05:20 AM
Registered User
Quote:
Originally Posted by Av8Chuck
I'm new to this controller but my first PixHawk did the same thing. I called 3DR support and although it took a bit longer for them to reach the conclusion than I might have liked, when things don't work right I'm not sure anyone could ever fix it fast enough, but after several tests they concluded that I had a hardware failure.

I started getting bad gyro health warnings, when I did and was hooked up to the GCS the artificial horizon would slowly start to roll.
I'm starting to think I may have a problem board as well. I can't believe the number of random, but mostly Bad Gyro Health faults that keep preventing me from flying. I suspect another fault materialised while flying and basically took over the X8.
Mar 11, 2015, 07:41 AM
Registered User
R_Lefebvre's Avatar
There have been some hardware faults with 3DR Pixhawks related to the gyro. Suspected dates are I think July 2014 to... sometime in the fall? Maybe even December?

But the #1 cause of gyro issues, is moving the copter while the Pixhawk is booting up.
Mar 11, 2015, 10:21 AM
Registered User
Can someone please confirm this for me.

Purchased Pixhawk and added GPS via drop down add feature from 3DR. GPS came with cable already attached to unit with 6pin in GPS with a 5pin end to connect to Pixhawk. The GPS and Pixhawk both have 6pin connection ports and when I look at the GPS mast kit it states a 6pin to 6pin (DF13) is for the Pixhawk and the 6pin to 5pin is for a APM 2.6. Did I get the wrong cable?


If I did get the wrong cable that is fine because I need a longer GPS cable anyway, so do I need to find a 6pin to 5pin or can I just use a standard 6pin to 6pin (DF13) cable?
Mar 11, 2015, 10:46 AM
Soon to be CrashMasterPhil
The GPS comes with both the 6 to 5 and a 4 to 4 pin cable. None should be attached from 3dr. The GPS ships in it own within the bags that has the cable and a "3dr Learn" Card. Put the 6 to 5 pins cable in your junk drawer has there's no use for it with the pixhawk. The Pixhawk box should have the correct 6 to 6 pin cable.

The GPS mast should also have a long 6 to 6 pin cable and a shorter 4 to 4 pin cable. No idea why the 4 pin is shorter.

Quote:
Originally Posted by Merkyworks
Can someone please confirm this for me.

Purchased Pixhawk and added GPS via drop down add feature from 3DR. GPS came with cable already attached to unit with 6pin in GPS with a 5pin end to connect to Pixhawk. The GPS and Pixhawk both have 6pin connection ports and when I look at the GPS mast kit it states a 6pin to 6pin (DF13) is for the Pixhawk and the 6pin to 5pin is for a APM 2.6. Did I get the wrong cable?


If I did get the wrong cable that is fine because I need a longer GPS cable anyway, so do I need to find a 6pin to 5pin or can I just use a standard 6pin to 6pin (DF13) cable?
Mar 11, 2015, 11:50 AM
Registered User
Quote:
Originally Posted by slimething

So what are you going to do? Continue using the M8N or switch back to the LEA-6H? What really frosted my cookies was CSGShop's knee jerk response it was a Pixhawk issue.
That's the tough question. On one hand I feel like going the proverbial l "if it ain't broke, don't fix it" route. On the other, I can't afford both from a money and safety standpoint to play Russian roulette ....

But since I've seen the same issue (at least once) with the 3DR GPS it doesn't make sense for me to switch back. And flying in GPS poor environments with hdops around 2 with the 3DR GPS is no answer either for me.

Most of my m8n logs show a positive yet steady INAVerr (and in 90% of cases < 255) during flight, except one shooting up in flight. Same with 3DR GPS except most are at zero, except one that I showed earlier that does shoot up in flight too. So at this point everything I've seen is inconclusive. And my experience definitely supports the fact that the M8N is better. (That's easy to see. You can just compare the position drift of an M8N and a 6 generation GPS while they are at rest in Ucenter or on a copter on MP, in same location and environment. Night and day difference).

So I am going to keep going, but be extra careful, also follow closely on what's being said on the DIYdrones related threads and others (I am way behind on that). And get more information/find out in the code where the 255 value comes from (I suspect a cast or scaling or something) and try to understand better what's going on. I do think Randy has a great point when he talks about a red herring with INaverr, many reported problems may have to do with GPS glitches or other issues and INaverr is just a confirmation but is not specifically related to the M8. I am also taking with a grain of salt what the ublox guy is saying about the M8N extra sensitivity to noise. I of course agree with that, but I have yet to see any negative consequences in practice. Sure Inaverr is higher, but again, no actual issue flying ...

So keep going for now, also need to do more long auto missions with my finger closer to the stabilize switch ... Verify logs more closely, need also to analyze further past logs ... In short, more data and knowledge needed... All I've seen is too inconclusive for now imho ...

PS: I also suspect which m8 GPS one uses could make a difference. The CSGshop I have have a huge antenna. I also have a whitespy one with smaller antenna but haven't tested it yet. The newly introduced RCTimer one also appears to have a smaller antenna. This plus filters, could explain a lot of things ...
Last edited by jdennings; Mar 11, 2015 at 11:58 AM.
Mar 11, 2015, 12:53 PM
Registered User
mlebret's Avatar
Hello,

I logged two flights today with two different M8N, with arducopter 3.2.1

First one was with a ÁBrain5.1 and M8N from Virtual Robotix. Sat Number is around 20 and HDop close to 1. INAVerr climb then stay at 255 during the end of the flight. Second part of the flight was an Auto navigation (34 wp) with RTL at the take-off point.

Second was with VRBrain 5.2 and M8N from Witespy (35x35mm). Sat number was close to 15, Hdop around 1.2, and INAV climbed to 9 before take-off then stayed at 9 during all the flight.

Same place, two consecutive flights.

M8N settings may be different but INAVerr count had no incidence on the flight
Marc
Last edited by mlebret; Mar 11, 2015 at 12:55 PM. Reason: typo
Mar 11, 2015, 12:58 PM
Registered User
Quote:
Originally Posted by divemasterphil
The GPS comes with both the 6 to 5 and a 4 to 4 pin cable. None should be attached from 3dr. The GPS ships in it own within the bags that has the cable and a "3dr Learn" Card. Put the 6 to 5 pins cable in your junk drawer has there's no use for it with the pixhawk. The Pixhawk box should have the correct 6 to 6 pin cable.

The GPS mast should also have a long 6 to 6 pin cable and a shorter 4 to 4 pin cable. No idea why the 4 pin is shorter.

Got it, thanks!
Mar 11, 2015, 04:12 PM
Registered User
i've been ground testing a cgs shop m8n indoors and out. inaverror doesn't appear to be fluctuating for me although its being logged.
Mar 11, 2015, 05:16 PM
Registered User
Quote:
Originally Posted by jdennings
That's the tough question. On one hand I feel like going the proverbial l "if it ain't broke, don't fix it" route. On the other, I can't afford both from a money and safety standpoint to play Russian roulette ....

But since I've seen the same issue (at least once) with the 3DR GPS it doesn't make sense for me to switch back. And flying in GPS poor environments with hdops around 2 with the 3DR GPS is no answer either for me.

Most of my m8n logs show a positive yet steady INAVerr (and in 90% of cases < 255) during flight, except one shooting up in flight. Same with 3DR GPS except most are at zero, except one that I showed earlier that does shoot up in flight too. So at this point everything I've seen is inconclusive. And my experience definitely supports the fact that the M8N is better. (That's easy to see. You can just compare the position drift of an M8N and a 6 generation GPS while they are at rest in Ucenter or on a copter on MP, in same location and environment. Night and day difference).

So I am going to keep going, but be extra careful, also follow closely on what's being said on the DIYdrones related threads and others (I am way behind on that). And get more information/find out in the code where the 255 value comes from (I suspect a cast or scaling or something) and try to understand better what's going on. I do think Randy has a great point when he talks about a red herring with INaverr, many reported problems may have to do with GPS glitches or other issues and INaverr is just a confirmation but is not specifically related to the M8. I am also taking with a grain of salt what the ublox guy is saying about the M8N extra sensitivity to noise. I of course agree with that, but I have yet to see any negative consequences in practice. Sure Inaverr is higher, but again, no actual issue flying ...

So keep going for now, also need to do more long auto missions with my finger closer to the stabilize switch ... Verify logs more closely, need also to analyze further past logs ... In short, more data and knowledge needed... All I've seen is too inconclusive for now imho ...

PS: I also suspect which m8 GPS one uses could make a difference. The CSGshop I have have a huge antenna. I also have a whitespy one with smaller antenna but haven't tested it yet. The newly introduced RCTimer one also appears to have a smaller antenna. This plus filters, could explain a lot of things ...
Hi Jdennins,

I completely agree with the content of your post and I think it's a good summary of what has been seen / told .
As you say, these INAVERR have been logged With 3DR GPS
I am almost convinced that more testing / analysis should be done with different M8N GPS boards
Quote:
Flying in GPS poor environments with hdops around 2 with the 3DR GPS is no answer either for me....
...And my experience definitely supports the fact that the M8N is better. (That's easy to see. You can just compare the position drift of an M8N and a 6 generation GPS while they are at rest in Ucenter or on a copter on MP, in same location and environment. Night and day difference).
Yes , for me this are the valids points witch need to investigate further the real meaning and effect of this INAVERR

I have not followed all the discussions about this INAVERR.

Could you please point me to a post or link describing exactly what is the meaning of this INAVERR ?
What are the conditions with lead Arducopter PM code to increment this INAVERR counter ?


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