Interfacing NMEA Data to Computer

[oprlid]

Originally Posted by bobfnbw

This is interesting.
Kind of what I had in mind. but I do not see any screen shots of what it would look like on a pc with a charting program.

Well - that depends on the charting program you're using.


A converter just translates SeaTalk data from your SeaTalk instruments (ST60) into a NMEA Format, that your computer can read and that your charting program understands.

Your Computer can't Read or Write SeaTalk Data directly.
It can read and write NMEA.
Now - if we want to get Data from SeaTalk Instruments to the charting program ( Windspeed / Depth / Water Temperature ...... ) we somehow need to translate it from SeaTalk to NMEA.

Or - if we want to send Position or Speed over Ground Data from your Computer to SeaTalk Instruments,we somehow need to translate it from NMEA to SeaTalk.

That's basically all a converter does.

!!! If your ST60 Instruments allready should have NMEA output , and if you don't want to send anything from the Computer to the SeaTalk instruments - than you don't need a converter.

Orplid

[hellosailor]

bob-
Two "gotcha"s to expect. The pfranc interface is one of the few with a great reputation that is not Windows Logo Certified. Keyspan and IBM are certified as are a few more brands these days. Pay the extra $5 to get a certified brand (if you're not getting the pfranc) because it means they have been more rigorously tested and are far more likely to WORK.

The other gotcha is that in NEMA/RS-232 terminology you'll see "RX" and "TX" meaning the "receive" input and "transmit" output lines. Except, you need to keep in mind that a wire which goes to "TX" on one end, goes to "RX" on the other end, at the other piece of equipment, most of the time. I've seen a lot of manuals that make it totally unclear which side of things they are referring to, so expect RX and TX may be confused.

And a wire run doesn't have to be that simple, you can for instance have two "talkers" connected in a "Y" cable to one "listener". Two TX connections going into one RX connection. Assuming all your devices will speak the same NMEA version, because some will speak 183.0 but not 183.2 or 180.1 but not...you know, whatever the numbers actually are. (It is late, I don't have them memorized.)

[Pblais]

Two "gotcha"s to expect. The pfranc interface is one of the few with a great reputation that is not Windows Logo Certified

It works under Windows Vista and Windows 7. There are no device drivers required for newer versions of Windows for the pfranc. The XP driver is available for download and it works fine as well. There really are a lot of bad cheap USB to serial devices out there that won't work for this application.

NMEA allows three listeners per talker on the same line. So you could split the output form a GPS and connect it to the DSC on the radio the Autopilot and an RS232 port for a computer. The other option is input it all to the computer and then make a second port be the output. It then can do more things in software to support a few other options or support more sentences.

You can't talk and listen of the same port at the same time. You have to stop one mode and switch modes to do that. You would do that for example if you wanted to upload a route to a GPS. You can use the same connection but you can't monitor GPS data at the same time as updating a route. Most GPS's also require you to manually set them to receive mode to take in data as well.

[fairbank56]

We use these bluetooth multiplexers on the new fleet of Navy 44's at the Naval Academy. Work great with laptops with bluetooth and has built-in seatalk conversion. Not a good idea to connect multiple talkers to one listener directly. You can "diode or" them together but you will still have collisions so you should really use a multiplexer for that.

Eric

[Pblais]

Globalsat has a new Bluetooth BT-368 GPS. Fits in the palm of your hand 40 x 70 x 9 mm in size. Made primarily for the Bluetooth smart phone crowd but could be cool aboard. Pretty cheap too at about $60. They also have a USB dongle too. It has no user interface so you need to tie the signal to software on a Bluetooth enabled device. The new SiRF star III chipset is doing some nice stuff. It's been designed for doing urban street navigation so the receivers are pretty robust making them even better aboard.

I am going more toward wireless instrumentation. I also see using handheld devices more instead of repeaters that are hard wired. The Bluetooth multiplexer looks very nice. TackTick does this with all their wireless instruments but they don't use Bluetooth as it uses to much power. It's about the same price though. Their NMEA unit is hard wired as are the through hull transducers. Everything integrates itself automatically via wireless LAN and the displays and wind transducer are solar powered. The LAN was set up to conserve power. The wind instrument can run basically forever with no outside power. They all integrate the available data to display some complex things like true wind speed and true direction. Getting rid of the wires is so much nicer. The money you save on installation right now makes up for the increased price and the portability is a bonus.

[hellosailor]

"The new SiRF star III chipset "
I thought that was already about 5 years old, and a generation IV chipset with much lower power consumption, and still slightly higher sensitivity, had been out for over a year now?

[scotte]

Originally Posted by hellosailor

"The new SiRF star III chipset "
I thought that was already about 5 years old, and a generation IV chipset with much lower power consumption, and still slightly higher sensitivity, had been out for over a year now?

Hellosailer is 100% correct as far as Sirf Star III goes. It was released at the start of 2004 - SiRFstarIII Runs Hard and Fast on GPS Signals to Make Life Easy for LBS Users; Speed and Sensitivity Breakthroughs Highlight Third-Generation GPS Architecture. - Free Online Library. My Garmin GPSMap76CSx has a Sirf Star III chipset, and it came out at the beginning of 2006 (and was hardly the first - various other (non-Garmin) units were released in 2004 and 2005). Definitely been around a few years...

[Pblais]

No products, the III products are only about 3 months old. The new IV is lower powered but what they are doing is using predictive logic on the ephemerids to cut lock time. In a smart phone driving downtown locks are very difficult. Guess who can buy any phone they want? Inside a car is the same problem going in and out of shadows. III shuts down to save power where IV does not totally shut down but goes into a suspend mode so it can jump out faster. That is the "new lower power feature". On the water you couldn't lose lock unless the US Navy blasts you with an EM pulse (been there it lasted about 1/2 day and whacked the wind instrument too).

The whole point of IV really has little to do with anything you might need on the water, but of course smart phones now could be a great hand held nav tool. III already does a shutdown if you lose blue tooth lock for 10 seconds. If you shut down the device you don't need to worry you forgot the GPS receiver because it does so already. It just has no way to go back on on it's own. That is what they want for cell phones.

The IV is pretty darn small. You could line up 6 chips across a US dime. and probably fit almost 2 dozen on the surface of a dime. They expect to sell them for cameras and cell phones and they could be pretty much standard in a couple years built into anything. Lowjack for your fridge.

[barnakiel]

Like what makes you think Ray is NMEA ???

I believe you need the SeaTalk-Nmea box (from Ray).

b.

[scotte]

Originally Posted by barnakiel

Like what makes you think Ray is NMEA ???

I believe you need the SeaTalk-Nmea box (from Ray).

Which bit are you replying about? You may or may not need one, many Raymarine devices support NMEA0183 out of the box. Including the ST-series instruments (though output only), which was the original topic of this thread... Unfortunately it has drifted in several different directions.

[barnakiel]

As per Beausoleil expl - ST60 no NMEA, box required. Newer ST60+ NMEA.

From the box as per earlier posts. Some problems may be expected as the Ray interface box is problematic for the PC when it is not the only talker on the system (like if you have your Ray instruments and say an AIS box from another company). Getting things in via different COMs is not all that great either given Windows problems with re-establishimg COM/ USB things on re-start or re-connecting.

It is all very simple to cable but then sometimes gives trouble to get it all work.
b.

[scotte]

Originally Posted by barnakiel

As per Beausoleil expl - ST60 no NMEA, box required. Newer ST60+ NMEA.

*sigh* Again, ST60 does have NMEA output on some instruments. Why do people continue to insist it does not? Here, go to page 8 of this ST60 (NOT ST60+) manual: http://www.raymarine.com/SubmittedFi...81039_4www.pdf

[blubaju]

for 9 years I had my PC (with build-in RS232) directly connected to my Raymarine (then Autohelm) Autopilot, to the NMEA_in and NMEA_out connectors and never had a problem. No mux, no special Raymarine hardware, PC Navprogram directly controling the autopilot. Today I use openCPN, freeware and displays ENC (free for US) and CM93/2 and BSB raster charts.

Read this site with tons of information and further links how to do it

Peter Bennett's GPS and NMEA Site

[rodney_k]

Originally Posted by blubaju

for 9 years I had my PC (with build-in RS232) directly connected to my Raymarine (then Autohelm) Autopilot, to the NMEA_in and NMEA_out connectors and never had a problem. No mux, no special Raymarine hardware, PC Navprogram directly controling the autopilot. Today I use openCPN, freeware and displays ENC (free for US) and CM93/2 and BSB raster charts.

Read this site with tons of information and further links how to do it

Peter Bennett's GPS and NMEA Site

Same here. Then, one day, I decided I wanted speed, depth, wind speed & direction data on the laptop (which lives in the nav station). The additional data is nice when making my hourly log entries. I have ST50 instruments which do not have NMEA out so I bought the E85001 NMEA interface and all was good. Not life & death, but nice.

Then, along comes AIS, and I decide I want AIS on the laptop (at the Nav station) and on the chartplotter at the helm. AIS data runs a 38400 baud while NMEA 018x runs at 4800. The Brookhouse mux provided the data speed conversion functionality. The Brookhouse mux also replaced the E85001. While I was at it, the mux also made it possible to supply NMEA position data to the DSC capable VHF, and to the SCS Pactor modem for automatic position reports whe using the SSB on Winlink or Sailmail.

I agree, for basic position data and direct computer control of the autopilot nothing additional is needed. But if you want more data displayed on the laptop and elsewhere, then your system has to grow. That is my story & I am sticking to it! And don't even ask what it was like trying to get a laptop, a Standard Horizon chartplotter, a Garmin chartplotter, a ST7000 autopilot, and ST50 instruments all to play nice with each other. Plug & Play? I think not.

[Pblais]

Raymarine auto pilot course computers have had NMEA IN for years. My 1991 ST7000 does.