[TG] [TG11] ST2000+ not heading correctly in track mode

[[email protected]]

Hi There,
I have an ST2000+ tiller pilot interfaced (by via ST1 to STNG converter) with ST60+ instruments and an A70D Plotter/MFD.
Communication seems to be working ok, pilot pop ups appear on the ST60 displays and wind and track data appear on the ST2000+ When it is in the appropriate modes.

I can set up a route or waypoint and enter in to track mode ok.
However, I have noticed one glitch when the autopilot is in track mode.

Although BTW, Heading and COG all appear to be sensible, the autopilot seems to want to head 10-15 degrees to port of the BTW. I have tried this on a range of track headings.
I suspect that the error is that magnetic variation (about 13E here) is being applied once too often somewhere in the system.
I have variation in auto on the ST 60+ Graphic and on the A70D plotter.

Could you please advise the correct variation settings for each instrument/display and let me know if there are any other configuration changes I should check out and correct?
I am planning further test in the next few days, so if there’s anything I need to do to get you more data to work with please let me know.
Regards
Dave Davies.

[Tom - Raymarine - Moderator]

Hello Dave,

Well spotted! If a pilot steers well in Auto but not in Track mode then a heading error is almost always the cause, and incorrect or inconsistent Variation is a very common cause. For anyone else reading this, chartplotters work in True, whereas pilots steer to magnetic heading, so a conversion for the local magnetic variation needs to be applied. Depending on what's connected and how, the applied variation can be correct, inverted, double-applied or zero, and all except the first of these will cause incorrect conversion and inability to steer correctly in Track mode.

In your case, Dave, I think you're not getting variation through the convertor from the A70D on STNG to the ST1 side. One test for this would be to toggle the ST60+ Graphic between True and Magnetic heading display. I suspect you'll see both showing the same value (zero variation.)

You can manually configure variation on the ST2000+ in the Calibration menu. See section 6.1, p60 of the ST2000+ handbook.

Regards,
Tom

[[email protected]]

Hi Tom,
thanks for the advice, what I have found I needed to do to get the system to work was to:
- set the variation to 13E on the ST 2000+
- set the variation to zero on the A70D
- set the bearing mode to magnetic on the A70D

The boat tracks perfectly now.
I think the problem was that both the ST2000 and the A70D were sending variation to the system and this was causing confusion.

thanks
Dave

[Chuck - Raymarine - Moderator]

You're welcome.

[tlinnant]

Hello,

Im new in this forum. Founded this thread which handles quite similar problem we are facing.

We have Axiom Pro MFD and ST2000+ autopilot connected via N2k to ST? converter.

I have faced out problems that when changing from auto mode to track mode the new heading seems to be, I assume, the one which is there in the next way point pairs legs great circle.

Also when pressing Restart Cross Track Error in Axiom, the pilot takes some weird heading. At the present moment I can't say more than this about this Restart phenomenon.

Wind mode seems to work well. And pilot gets the waypoint information presented in the UI.

Example: Route activated in Axiom. Now on pilots auto mode. XTE less than 0.1 NM, well on the same heading than current waypoint pair. Then, turn on the track mode, the new heading in the ST2000+ seems to be close to the heading which exist in the next waypoint pair leg. The incorrect headings have been both to starboard and to port depending on the route. And the magnitude of incorrect headings have been in some cases greater than double of magnetic variation.


Q1: is the whole track part of the N2k message feed? Or just the current leg + following leg?
12: might the ST2000+ have some kind of indexing issue, so that it gets the incorrect heading from the next leg?

Kr. Tuomo

[Tom - Raymarine - Moderator]

Hello Kr. Tuomo,

The navigation data sent on NMEA2000 is a bit more complex, but on Seatalk1 it's very simple and is definitely only the current leg. It's a good thought but I don't think that sort of indexing problem is the problem.

Would it be possible to give me some specific real-world examples, or better still a video of the problem so that I can see the interaction?

Thanks,
Tom

[tlinnant]

Hello Tom,

Thank you for your message.

Due to that I'm new in this forum I'll try to make my best to post a video of the problem. I'll record a video next time when I'm sailing.

For some reason, in this thread, I don't see my own post?

Thanks,´kök.-

Tuomo

[Tom - Raymarine - Moderator]

Hello Tuomo,

I'll look out for the video. You don't see your post straight away as all posts have to be approved by a moderator, in order to prevent spam.

Regards,
Tom