Help me again

[Scofield]

Hi Curt,Thanks for your help !

Between the MNAV100CA and the computer can been connected by the serial port.

Now ,i meet some problems when i use the Micro-view software for calibration. I always don't pass the calibration,the "Failure" with some help message is shown though i follow the instructions for the calibration procedure .The main promote message is "the magnetometers X Y Z axis for calibration is failure".

I want to know how to calibration magnetometers and need to notice others things.Thanks for your help again !

[clolson]

I'm not a calibration expert. I believe there are detailed calibration instructions in the MNAV documentation/manual. Also, your MNAV should have shipped with with a single sheet printout of all the factory calibration values. If it was me, I'd stick with their numbers rather than recalibrating myself.

Unfortunately, if you power your MNAV from battery and run the battery voltage too low, it's possible to corrupt your MNAV firmware (at least on earlier versions of the unit.) So if you do run into this situation it may be necessary to re-input the factory calibration values, or possibly even reinstall the firmware, and in a worst case scenario, you may need to send the unit back for Xbow to repair if the firmware loading portion of the firmware gets munged. That situation should be very rare though.

At any rate, if you are at the level of calibrating your unit and have questions that aren't clearly answered in the documentation, you may be better off contacting Xbow tech support directly and talking to an expert rather than posting here and getting answers of possibly varying quality and content. :-)

Regards,

Curt.

[Unterhausen]

I have calibrated the micronav, and it isn't really all that easy. If you move it the wrong way, the calibration routines don't work. I don't remember having problems with the magnetometers, but you have to recognize that they are strongly affected by metal objects and proximity to the ground. So you need to be at least 2 feet away from those things. Particularly, you need to be away from the computer.

There is some activity on the sourceforge forum for the micronav, you might want to ask there.

[clolson]

I've always wondered if magnetometer calibration might be better done outdoors (or maybe installed in your airframe?) I'm just wondering ... I know I get radically different output from the magnetometers when inside my car versus inside my uav versus inside my house.

Curt.

[Unterhausen]

you probably should do the calibration in your airframe, but the problem is you can't do it on the ground, maybe put them on a pvc test stand? A metal stand would be bad. I guess they are different inside your house because of all the 60Hz electromagnetic interference.

Magnetometers are a pain. maybe some kind of auto-calibration would be best?