Can I get an Autohelm 4000 /ST50 /Seatalk Brief?

[hertfordnc]

The boat came with the Autohelm 4000, tridata, ST50 speed and depth.

The system seems to work fine except for certain functions that require it to share data with itself like auto-piloting to a given wind direction.

What is Seatalk and how do I know if i have it? There are no cables or devices at the nav station. The boat came with a vintage MicroLogic GPS.

I've downloaded and read most of the manuals.

Given that this is a bit vintage, what older Raymarine GPS might interface with it?

thanks

[capttb]

If you turn on the light on one instrument all the instruments lights will come on if Seatalk is connected. Any GPS with NMEA should be able to interface with the autopilot and it won't steer to wind direction if you don't have a wind instrument, a tri-data is depth, temp., and speed.

[sailingdog]

Seatalk is a proprietary serial protocol developed by Raymarine which is used to allow their various instruments and equipment communicate with each other. As CaptTB points out, the autopilot can not steer to apparent wind without a wind instrument that is capable of talking to the autopilot.

Also, most GPS units that output NMEA 0183 serial protocol will talk to your autopilot.

You can probably download the manuals for the gear you have at Raymarine's website.

[hertfordnc]

Originally Posted by capttb

If you turn on the light on one instrument all the instruments lights will come on if Seatalk is connected.

Excellent info- thanks. I have ST50 wind, depth and autopilot. Wind and depth both illuminate when i press the light button on either one but the autopilot does not share.

Does that suggest something is not connected?

[sailingdog]

The autopilot won't come on when the instruments do... that is by design, since most of the time, you want the instruments on, but not necessarily the autopilot, and it draws the most energy.

If you hit the buttons on the autopilot, it should come on. If the GPS is on, you should be able to set a course and see what the heading is on the autopilot. Most of the autopilots have three modes: 1) steer a compass course, 2) steer by apparent wind, and 3) steer by GPS course/route.

[hertfordnc]

Actualy, they each come on when I flip their respective breakers- one for the autopilot and one for the depth and wind. Depth and wind are talking to each other as it seems to provide true and apparent wind speed. So seatalk is present and working for those two? Am i correct in assuming it should be able to talk to the autopilot also? Should I be looking for a bad connection?

thanks

[sailingdog]

Again, it depends, many times the autopilot isn't connected to the wind/speed/depth instruments, since there is no real need to do so, unless you want to be able to have it steer by apparent wind.

[hertfordnc]

OK, i went to the boat and removed the panel behind the instruments. I have an unused round connector dangling from the wind speed and two empty ports on the Autohelm labeled NMEA. These are flat.

I am beginning to understand. What's the dofference between NMEA and Seatalk. Can they connect with just a cable or is there more to the process?

[capttb]

Seatalk is Raymarines' proprietary format so all Raymarine instruments can share data, as Dog mentioned. There's "old" Seatalk with round connectors and "new" Seatalk with square plugs, they are compatible except for the connector shape and a new to old adapter is or was available. Seatalk uses 4 conductors or wires, NMEA 0183 is a format which allows GPS receivers to "speak" to instruments from different manufacturers and uses 2 wires. Most GPS receivers use a proprietary format by default but can be programed to output their data in NMEA 0183 to interface with AP's and radios etc.
Newly manufactured instruments use NMEA 2000 which will allow all instruments to communicate thru a common bus.

[artbyjody]

Originally Posted by hertfordnc

OK, i went to the boat and removed the panel behind the instruments. I have an unused round connector dangling from the wind speed and two empty ports on the Autohelm labeled NMEA. These are flat.

I am beginning to understand. What's the dofference between NMEA and Seatalk. Can they connect with just a cable or is there more to the process?

You'll need the Raymarine Laptop NMEA to Seatalk interface... its $125 retail and provides the NMEA to Seatalk conversion that you will need. And no you do not need a laptop or pc hooked up. You use this a "Bridge" between interfaces like an auto pilot etc. Most Raymarine stuff need it is Seatalk format - I use a Simrad WP30 where I tie the NMEA inputs to it as out put...on a Raymarine instrument setup. NMEA tie ins can carry enough signal to bridge up to four devices at about less than 6 feet - less than 4 you can get up to 8. Most autopilots are recieve only NMEA in - and therefore easier to configure and work with..