Compass reading from pixhawk and external at the same time

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1

Hi there

Having set “PX/Pixhawk” in compass setting in mission planner.

PROBLEM:
both compass on the pixhawk and the external gps module are active…at the same time

Can anybody help !..

nb. using latest firmware and latest missionplanner.

Best regards
Stone

2

Stone, how do you know both compasses are active?

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3

hi marimach77

I have the pixhawk and all on the bench…

In mission planner, if I turn the pixhawk, the compass rose in mission planner moves. if I then turn the gps/compass module, the compass rose in mission planner moves again…

I dont think that right… it should be internal OR external…not both active on the same time…

4

Hi Bison,

The Pixhawk autodetect the external compass, you just need to select the “PX/Pixhawk” as you already did, one the external compass is detected you can see the COMPASS_EXTERNAL parameter will be set to 1.

The APM is different and if you are using a board with internal compass such as APM 2.5, you need to physically disable it.

If you do the compass calibration, are you getting errors?

5

[quote=“bison”]hi marimach77

I have the pixhawk and all on the bench…

In mission planner, if I turn the pixhawk, the compass rose in mission planner moves. if I then turn the gps/compass module, the compass rose in mission planner moves again…

I dont think that right… it should be internal OR external…not both active on the same time…[/quote]

The gyros in the pixhawk (or APM) will cause the heading data to change when the machine is rotated. Assuming that the compass is not attached to the frame with the pixhawk:
1 . when the compass is rotated the heading value will change slowly and finally settle at the new value
2. When the pixhawk is rotated the heading value will change rapidly then slowly return to the old value (determined by the compass)