Compass Mod Values

The Editor · Mar 12, 2015

OK.... back in the day of Mr Guinn and his famous Phantom the tutorial videos always informed users that after a compass dance you should be looking for the optimum mod value of circa 1500.
Indeed, if you look in any of the Naza publications a figure of between 750 to 2250 is acceptable (1500 optimum) with a vector range of -500 to +500.
However, after trawling through the Inspire publications/videos I can find no such recommendation for an 'optimum value'
Hearsay and urban legend recount figures of between 1400 to 1600 (that magic 1500 number in the middle again) as being the holy grail but I have not seen an official stance on this.

I notice the compass on the Inspire is much more sensitive than previous models/Flight control systems from DJI (which I know is part of the GPS/Atti problem) but my compass mod hovers around the 1500 area dipping to the low 1400's and peaking at around 1530 while I sit and watch it on the ground. I might add I have had ZERO problems but it would be nice to get an official 'nod' as to what the optimum mod values should be.
This way, if one were to do the compass dance and got a figure of say 1700(ish) but no error message, the user might be forwarned into trying another calibration to bring the value into the optimum range.

We have 'official' numbers for the IMU but not for the compass.......

Can @blade strike or @Tahoe Ed maybe shed some light on the mod values we should be looking for or get an DJI guru to confirm the magic '1500' number?

Thanks

gray52 · Mar 12, 2015

Mine dropped out of GPS today, for about 3 seconds, at the same time as lose of transmission signal at about 300m the all was fine again. Just be aware anything could happen!

Quadpilot · Mar 13, 2015

The Editor said:
OK.... back in the day of Mr Guinn and his famous Phantom the tutorial videos always informed users that after a compass dance you should be looking for the optimum mod value of circa 1500.
Indeed, if you look in any of the Naza publications a figure of between 750 to 2250 is acceptable (1500 optimum) with a vector range of -500 to +500.
However, after trawling through the Inspire publications/videos I can find no such recommendation for an 'optimum value'
Hearsay and urban legend recount figures of between 1400 to 1600 (that magic 1500 number in the middle again) as being the holy grail but I have not seen an official stance on this.

I notice the compass on the Inspire is much more sensitive than previous models/Flight control systems from DJI (which I know is part of the GPS/Atti problem) but my compass mod hovers around the 1500 area dipping to the low 1400's and peaking at around 1530 while I sit and watch it on the ground. I might add I have had ZERO problems but it would be nice to get an official 'nod' as to what the optimum mod values should be.
This way, if one were to do the compass dance and got a figure of say 1700(ish) but no error message, the user might be forwarned into trying another calibration to bring the value into the optimum range.

We have 'official' numbers for the IMU but not for the compass.......

Can @blade strike or @Tahoe Ed maybe shed some light on the mod values we should be looking for or get an DJI guru to confirm the magic '1500' number?

Thanks

I'm not Ed or Blade, but I can confirm that the 1400-1600 compass mod value as being the ideal range has been confirmed on RCGroups.

The Editor · Mar 13, 2015

42 views and only one reply??..... Though people might be a little more concerned with knowing what the official line is on mod values for the compass?

Quadpilot said:
I'm not Ed or Blade, but I can confirm that the 1400-1600 compass mod value as being the ideal range has been confirmed on RCGroups.

Thanks Quadpilot - who was it over on RCGroups? Was it Ed or Blade or someone from DJI or was it another consumer? What I'm after is an 'official' confirmation (or as near as we can get) on that magic 1500 number.

airdrone · Mar 13, 2015

Nokia 6210 is a good tablet

The Editor · Mar 13, 2015

airdrone said:
Nokia 6210 is a good tablet

?????....... I'm confused as to what this has to do with this thread!

Quadpilot · Mar 15, 2015

The Editor said:
42 views and only one reply??..... Though people might be a little more concerned with knowing what the official line is on mod values for the compass?

Thanks Quadpilot - who was it over on RCGroups? Was it Ed or Blade or someone from DJI or was it another consumer? What I'm after is an 'official' confirmation (or as near as we can get) on that magic 1500 number.

Both Ed and Blade have stated this range a number of times, to the best of my recollection. Just remember, this is a range, not a precise value. Some locations will have a lower or higher number than others. Would I not fly if my compass after a successful calibration showed 1390 or 1625? Well, I might try re-calibrating, but if that's the final value, hover for a minute or two, and if everything seems fine, fly on!

DodgeP · May 23, 2016

Between Philadelphia, PA and Princeton, NJ I have never had a compass mod value above 1425. My mod value always seems to be between 1350 and 1395.

Jimmykjimmy · May 24, 2016

The Editor said:
42 views and only one reply??..... Though people might be a little more concerned with knowing what the official line is on mod values for the compass?

Thanks Quadpilot - who was it over on RCGroups? Was it Ed or Blade or someone from DJI or was it another consumer? What I'm after is an 'official' confirmation (or as near as we can get) on that magic 1500 number.

Too anecdotal for my precise needs. When flying a $3,000 investment I'd like to feel confident. Hopefully, those in charge of the Holy Grail of knowledge will respond.

The Editor · May 24, 2016

Jimmykjimmy said:
Too anecdotal for my precise needs. When flying a $3,000 investment I'd like to feel confident. Hopefully, those in charge of the Holy Grail of knowledge will respond.

This is a very old thread now.

Think its pretty much accepted that calibrating your compass everytime you fly or every location change is not only a complete waste of time but also runs the risk of unknowingly introducing a bad calibration.
(I wont go into the technical reasoning behind it since I have done that else where on the forum)
Calibrate, leave it and forget it - but check your mods before every take off.

Experience has now told us (over 17,000 members on the forum and a good proportion now do not calibrate every flight/location) that 1400-1600 is about right. A little over/under is acceptable.