Connecting SMIS 4" NMEA2000 to Garmin 721xs

[Antares580]

I need some advise how to connect SMIS 4" NMEA2000 to Garmin 721xs.

Have a DF100A with only one SMIS 4" instrument, a Garmin 721xs and want GPS data into SMIS instrument to calculate fuel pr. nautic mile AND see engine data on Garmin.

Now the Garmin Works alone so does also SMIS with motor data.

Any suggestions?

[Solarman]

On the main forum page, look at the very first post. It shows many nema2k connections, and moonlighter should be able to answer your questions, if nothing related to your situation.

Good luck.

[Moonlighter]

Simple! I checked and your model Garmin is NMEA2000 certified and can display engine data. Check your Garmin owners manual or Garmin website for how to modify engine data pages etc once you have it connected up.

So to get them talking to each other, you simply add a new T piece to the NMEA2000 network, (put it between 2 existing T pieces) and put a NMEA2000 drop cable between the Garmin and the T piece. That's all the connections required.

(Note: you have to realise that you don't connect the Garmin to the SMIS gauge, you connect them both to the network, and then everything on the network communicates with each other through the network).

In the SMIS, data sources menu, select the Garmin and SOG for speed data. Probably the Garmin will automatically detect the network and settings will be fine, if not you may have to go into menu and set up - see your Garmin owners manual for how to.

[Antares580]

Thanks!

I have had some trouble with SMIS as it going white, going black, going "a big S" caused by low battery voltage. Perhaps it is connected to Garmin but have lost settings. SMIS, after Cold-start, must have new settings regarding temp (F/C) and everything with fuel. Perhaps setting for Connection with Garmin is lost...

I will change battery and see if NMEA2000 drop cable is fitted and try to select Garmin and SOG in data source menu for SMIS.

[Antares580]

The connection is done, black cable between "NMEA 2000" and T piece in the network - but still no talk together. SMIS se only "Engine interface". Garmin se only docking station for Iphone/radiounit.

Dont know what to do next....

[Moonlighter]

Is the Garmin turned on? It must be turned on for the network to see it.

Which part of the T piece did you connect the cable going to the Garmin to? It must be connected to the leg of the T piece, not the top cross-part.

Try going into the Garmin network menu and see what devices are listed there. Im not that familiar with the Garmin, but maybe check that networking is turned on.

Or try swapping the Garmin to a different T piece in the backbone - it is possible to have a faulty T piece and swapping should help you find out if that is the case.

[Antares580]

YES, the Garmin in on ;-)
However, there is someting funny about the installation.
3 T-pieces is connected in one network section with a 120R endresistor in both ends - and 3 other T-pieces is connected a second network also with 120R endresistor in both ends. It seems that they are not connected together....
Could that be the case? Do I miss the backbone extension cable...?

[Moonlighter]

It makes no sense at all to have 2 separate NMEA2000 networks on the boat.

And it would have been useful to know that at the start...... What other things are connected to the networks?

I'd suggest you make them into one network, just take 2 of the end resistors off and connect the end T's together.

But make sure you remove one of the power connections and the T piece it is connected to, you MUST make sure there is now only one power supply to the combined network otherwise BAD THINGS happen!!!!!!!

[Antares580]

I will make a drawing to sort thing out. Tried to upload a Picture but could not do it.