ST2000 and TackTick NMEA 0183 Problem

[nssailor]

Hi, 30' keelboat with existing TackTick network (wind, depth, speed, etc.) including NMEA interface. This is linked with a VHF DSC and a Garmin 720 plotter. I installed an ST2000 tiller pilot and fed it initially with the NMEA output from the TackTick NMEA interface (0183). Routes are derived from the Garmin plotter and display correctly (dist, bearing, XTE, etc.) on the TackTick network. However, when getting the ST2000 to steer the route it consistently takes up a course which is about 35 degrees to left of correct heading. I tried adjusting the declination setting in both network and tillerpilot but didn't change anything. (It is about 18 deg West here).

Changed the feed for the ST2000 to the output feed from the Garmin plotter and everything is fine. Problem is that the Garmin doesn't pass through the wind sentence to allow the ST2000 to steer to apparent wind angle so I lose some functionality.

Any suggestions where the problem may lie or how I can get full functionality?

Thanks,
Colin

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Colin,

Looped NMEA 0183 data may be responsible for the reported issue. In interfacing the equipment specified, it would typically be recommended that the NMEA 0183 output of the TackTick system and third party chartplotter be interfaced to a NMEA 0183 Multiplexer. More specifically,
- the NMEA 0183 output of the third party chartplotter would be paralleled to provided data from the chartplotter to the VHF radio and to the NMEA 0183 multiplexer.
- The output of the NMEA 0183 multiplexer would be directed to the autopilot's NMEA 0183 input port.

Interfacing the equipment in this manner would support permitting the autopilot to steer to wind, steer to a user configured heading (Auto Mode), or operate in Track mode.

[nssailor]

Hi Chuck,

Thanks for the reply. Just getting time, now that the boat is out of the water, to revisit this issue. Just to clarify ... both the output from the TackTick NMEA box and the output from the third party chartplotter would be interfaced to (eg) the Raymarine NMEA 0183 multiplexer? The output from the multiplexer would then be directed to the ST2000 input port?
The problem is that I don't believe the third party chartplotter passes the Wind sentence through, so without the TackTick NMEA feed, the multiplexer (and hence the autopilot) wouldn't get the Wind data ...

Is that the configuration you're suggesting?

Thanks,

Colin

[Chuck - Raymarine - Moderator]

Colin,

In looking at the Garmin GPSMap 700 Series manual, the product does not appear to support NMEA 0183 sentences which would include wind data. Accordingly, your choice to use a multiplexer is warranted. However, you need to be aware that the Tacktick NMEA 0183 interface will re-transmit data which it has received via its NMEA 0183 input port. Accordingly, it is recommended that that one of the following occur with the installation:
- if the multiplexer supports filtering of its individual ports, then the port which has been interfaced to the Tacktick NMEA 0183 interface should be configure to only pass NMEA 0183 sentences including wind data
- disconnect the Tacktick NMEA 0183 interface's input port from the Garmin 720's NMEA 0183 output port
- install a programmable NMEA 0183 multiplexer (ex. Actisense NDC-4-USB) between the Tacktick NMEA 0183 interface's output port and the NMEA 0183 input port of the currently installed multiplexer. Program the added NMEA 0183 multiplexer to only pass NMEA 0183 sentences including wind data

[nssailor]

Thanks again for the great info, Chuck. I purchased the Raymarine NMEA-0183 Multiplexer. With any configuration, I give up a little something, but what I've decided on is:

Tacktick NMEA out to multiplexer in (Port 2)
Garmin outputs (Port 1 (sentences filtered to only those that originate from the Garmin) to multiplexer Port 1 , Port 2 to VHF)
Garmin input Port 1 from Tacktick NMEA (doubled up with one to multiplexer) and Garmin input port 2 from VHF output
Multiplexer output only to Autohelm

There is no loop connecting Garmin to TackTick and back to Garmin before going to Autohelm .... like there was before, so hopefully this would work.

It preserves the vital functions that I use most. The only thing I give up is route/waypoint information displayed on my Tacktick mast instruments and remotes, but it is displayed on my Garmin which is cockpit mounted, so shouldn't be a major issue.

Fingers crossed that this works out but will have to wait until May to find out!

Cheers from Nova Scotia

[Chuck - Raymarine - Moderator]

You're welcome.