Getting Seatalk, Navbus and NMEA to talk…

Here’s a mystery…

The navigation electronics on Sunny Spells is a mix of Navman and Raymarine equipment. Navman has its own, proprietary communication protocol called ‘NAVBUS’. The Raymarine equipment uses ‘SeaTalk’. On top of this, there is the AIS receiver which transmits data in NMEA0183, but at 38,400bps (bits per second), while most NMEA equipment communicate at the slower data rate of 4,800bps. Sounds like a nightmare to get them all to talk?

Yes and no…

The core of the communications backbone is the Brookhouse multiplexer (MUX) with SeaTalk and AIS options and USB output. When I installed the MUX, I wasn’t expecting immediate success; imagine my delight when the whole system aapeared to work straight out of the box – no modification required!

However, I have started playing around on the chartplotter, and all is not as it seemed…

The data from the wind instrument is not available on the plotter or the Repeat 3100 (both on Navbus). I’m assuming it’s a Seatalk to NMEA conversion issue, but I haven’t been able to investigate as I can’t get the laptop connected. Unfortunately I seem to have mislaid the CD with the USB-Serial driver for the Mux, so I can’t get the laptop connection sorted – aaargh! I’d love to have the wind info on the plotter (which is at the helm) as the crew are forever blocking my view of the wind instrument!

[ad]

One Reply to “Getting Seatalk, Navbus and NMEA to talk…”

  1. Wout at Brookhouse replied to my e-mail today. (Thanks Wout for your prompt reply and the USB driver). Of course, I remembered this morning that I had printed out the user manual for the MUX and had bound it nicely, with a pocket for the CD, in the back…

    The MUX is now connected to the PC via USB. All operating at 38,400 baud as the AIS is also connected. Digiboat’s Software-on-Board shows all wind data present and correct (see screenshot). So where’s the problem?

    Looks like I’ll have to go to Navman for this one…

    Wind data displayed on SoB

Comments are closed.