Crazy AP Behavior (with Video!) / B&G Zeus2

[Whomda]

I have a problem with the 'N' Navigation mode of the Autopilot.

I made a live video of the problem:

https://www.youtube.com/watch?v=vBwMHkUSB28

When the Autopilot is placed in ‘N’ Navigation mode, it quickly redirects the vessel to 21 degrees away from designated waypoint/destination, despite seeming to correctly know the waypoint direction in the instruments.

Any suggestions?

[Brewgyver]

Obviously, Zeus wants you to go to Scorpion instead!

But seriously, is this an initial setup issue, or do you have a history of proper operation, and this is a sudden occurrence? If either the AP or the Zeus is new, were the dockside setup and seatrial completed and check out? Fluxgate calibration completed? Also, if the AP has been reset to defaults, the setup/seatrial have to be done again.

Oh, and B&G say the power for the Zeus must NOT be landed on the same terminal as the AP computer.

[Whomda]

Originally Posted by Brewgyver

But seriously, is this an initial setup issue, or do you have a history of proper operation, and this is a sudden occurrence? If either the AP or the Zeus is new, were the dockside setup and seatrial completed and check out? Fluxgate calibration completed? Also, if the AP has been reset to defaults, the setup/seatrial have to be done again.

Oh, and B&G say the power for the Zeus must NOT be landed on the same terminal as the AP computer.

There are no other anomalies with the AP, everything else seems to work ok. The fluxgate reading seems to match the magnetic compass.

As you can see from the video, the AP seems to know exactly the correct Heading it should be setting, but then when approved it actually sets a radically different heading. It says "Changing heading to 243, ok?" and then when you check yes it suddenly sets the heading to 255.

If there is some calibration that might be wrong, any guesses? Maybe it thinks there's some massive drift that it needs to compensate for. Not sure what it would be using for such a guess.

It's bizarre.

[Lunita]

Is the difference between desired and actual course about the same as the magnetic vs. True deviation in your area? Wondering if it is a mag. Vs. True setting in the set up?
Just guessing.

[Brewgyver]

They also have a tack avoidance logic that can alter the AP heading. With our usual prevailing wind tied in that might account for it. BTW, I'm in Ventura Harbor.
Did you reach out to B&G tech support?

[Whomda]

Originally Posted by Brewgyver

They also have a tack avoidance logic that can alter the AP heading. With our usual prevailing wind tied in that might account for it. BTW, I'm in Ventura Harbor.
Did you reach out to B&G tech support?

Interesting. I have this error commonly, and I think I was on a reach, but can't be certain. It was a low wind day, so I was motoring and Apparent Wind would be nearly on the nose no matter what direction I was going.

I did send an email to B&G tech support, no reply yet.

Thanks.

[Brewgyver]

"Low wind day..."
What? Light air in So Cal???? Never happened to me!
Don't know if you saw the notice, but Ventura had the harbor entrance closed for weeks due to shoaling. Had a couple weekends, plus the 3 day, on the boat fixing stuff, watching Red Box movies, nowhere to go, but plenty of wind. They finally get the entrance dredged, and spent two weekends in a row with not enough air to fart without it lingering.

I've noticed recently an unusual pattern with the wind South in the morning, working to West then Northwest later in the day. I think you have a setting in AP control for wind, normally set to Auto, may need to turn that off, at least while motoring. This may be a case of the Zeus' sailing logic outsmarting itself, as it were.

[David Clark]

Tech support from B&G will be a long ,painful process.I speak from experience (a long story)Their phone support is even worse .Hope the Cruser community can help

[rpmbnsf]

As a disclaimer I do not in any way shape or form claim to have any experience with this but was just talking with a cruiser yesterday about a very similar issue with his b&g. They found the issue to be generated from the b&g compass unit that happened to be in a forward compartment, it just so happened there were a whole bunch of bean tins stacked in front and right next to where this unit was located. Moved all the bean tins away from that compartment and problem resolved.

Mayhave nothing to do with your issue but thought it may be worth it to pass on.

[Whomda]

This is what B&G tech support replied:
The U-tube video did not open for me. Regardless. If the autopilot works correctly in AUTO mode, all functions of the autopilot are correct. Now, we add the navigator information. XTE, BOD, RMC, etc. Something must be off in these settings for the NAV function to error that far off.

Check the waypoint data you have. Make sure the proper NMEA sentences are turned ON in the SOURCE menu. Make sure software is up to date in the Zeus.

So they propose a check on NMEA settings, and general suggestions to check the nav information.

I'll play some more, thanks everyone for the suggestions. I do think it's a nav error and not a compass error, as the compass on the bus matches the magnetic compass. But maybe...

[Bor the Wolf]

Could it be it tries to steer back to a course line you defined earlier, and not straight to the waypoint?
AFAIK the off track information from the GPS is often used to control the AP. But it all depends on how you set it up, obviously.

[terrysandling]

Just a thought, if there is any metal near the fluxgate compass it potentially could cause a serious error , I have had the same problem crossing from the Marshall Islands to Panama ,it took some days before we found the problem,cans of fruit in tin cans packed near the fluxgate compass caused massive deviation problems ,good luck.n

[leftbrainstuff]

Originally Posted by Whomda

I have a problem with the 'N' Navigation mode of the Autopilot.

I made a live video of the problem:

When the Autopilot is placed in ‘N’ Navigation mode, it quickly redirects the vessel to 21 degrees away from designated waypoint/destination, despite seeming to correctly know the waypoint direction in the instruments.

Any suggestions?

There have been numerous posts about erratic ap behaviour with b&g gear. It seems that overly complex networks can be problematic. APs and overly chatty tritons seem to be part of the problem.

One post described in detail how the op root caused the issue by diagnosing network traffic.

We're about to start a full instrumentation upgrade with b&g. We're not upgrading our ap except to run a remote at the helm for the alpha 3000.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[Pyxis156]

Originally Posted by Whomda

When the Autopilot is placed in ‘N’ Navigation mode, it quickly redirects the vessel to 21 degrees away from designated waypoint/destination, despite seeming to correctly know the waypoint direction in the instruments.

Any suggestions?

Is there any chance you have more than one source of heading information on your network? If so, you need to go into all your Zeus2 units and make sure that they are set to the same heading source in the Network | Sources settings. I had a similar issue on our boat with a Maretron SSC200 as my intended primary heading source and a B&G ZG100 GPS antenna as a secondary source, but the GPS unit would sometimes be used as primary until I manually set the source. This led to seemingly random 10-20 degree course changes and rough starts like in your video. If you don't manually set the sources, my experience is you can get this kind of behavior.

Hope this helps...