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B&G Zeus < > Nexus - BTW off by 13degrees

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I have a Zeus T7 networked to a nexus server via a GND10 bridge. Hpx Compass on the nexus is calibrated and correct (reads magnetic), while the B&G gets compass and gps from a zg100 and on it too is correct and reading magnetic.

 

The problem comes when i plot a course to a waypoint on the Zeus (say its BTW 070) it ends up reading circa -13 degrees (ie BTW 057) on the nexus display. Seems pretty likely that a true/magnetic mismatch somewhere. But where?

 

I cannot find a menu to see what the b&g is tx onto the nmea2000 bus (to toggle it from M to T and see if that helps). The GND is in there too... Could it be miscoding nmea2000 btw magnetic to true and then the display is taking another 13degrees off?

 

Known issue?

 

What would you do next?

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A man who has one watch always knows what time it is, a man who has two watches is never sure.....

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I have a Nexus HPC on the server connected to GND10 and it outputs to B&G T41 Triton display on NMEA 2000. It seems to work ok with that. I have it set for degrees magnetic and auto variance.

 

Last year I was delivering a J/130 that had the T7 touch, B&G auto helm and T41 displays. Noticed the variance error like you saw when navigating to a waypoint. I just attributed it to a menu setup problem, but never went deep into it to find the fix.

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I had similar problem with Raymarine chart plotter & nexus system - I ended up manually over-riding the raymarine's settings by 13 degrees & all worked out fine.

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Did you check to make sure both units were both either reporting magnetic or true headings? The Nexus also has a manually set local deviation calibration that needs to be set to get correct heading.

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tech,

 

How did you manually offset the compass on Raymarine. I have the same issue.

I have the Raymarine S1G. There is a menu setting in the Seatrial Calibration section where variation can be set.

 

My Nexus system has an HPC compass and I also have the Raymarine Fluxgate compass connected directly to the S1G course computer. Just looking through the S1G manual and the course computer will accept NMEA compass information but reverts to the Raymarine fluxgate compass first if it is connected. I have noticed that the Raymarine fluxgate compass drifts a few degrees and I end up adjusting it every few weeks because when I press the autohelm engage button, the heading will jump a few degrees. After aligning the Raymarine compass it works fine again (no jumping). When I splash in the spring and realign everything, I am going to disconnect the Raymarine compass and see if the just the Nexus HPC compass stops the "course jump when engage" problem. Here is a link to my system connections.

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Old thread but in case someone missed it Garmin has a bugfix for he OP's issue. Data on the Nexus bus are corrected for magentic variance while that sent on the NMEA2000 network isn't. Update history here.

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