seatalk help

[SvenglishTommy]

Hi guys,

I'm having some trouble working out how/if I can get my instruments to talk to each other. Currently I have 4 old autohelm ST50 instruments connected. The chains goes: wind -> log -> depth -> GPS display. after this it goes to a GPS which I think is broken as it's about 300 miles out. Now I think I can get the plotter to send NMEA to the GPS display which I assume would then get the gps data on the seatalk bus.

I also have an autopilot which isn't hooked up to the seatalk bus, but I would like it to have the GPS and wind data in particular.

Finally I have a newer SL72 radar which I would also like to have in the loop, for the gps and compass data (this has the flat 3 pin seatalk connector, but only 1 not in and out).

Anyone know if it's possible to get all this stuff sharing info? I cant see how I'f get it all in a chain, or if it really needs to be chained.

Any advice appreciated.

 

[nimbusgb]

Seatalk bus is bidirectional so 'In' and 'out' don't matter.

Which Autopilot? if it has seatalk connection then one assumes Raymarine. if the GPS and wind data is on the seatalk bus then conecting seatalk to it will give the autopilot the data. However the autopilot may not be able to process raw GPS data, you may need some sort of plotter to tell the autopilot things like XTE. the wind angle should be processed by the AP though.

If your GPS is 'out' by 300 miles then perhaps there's a screwy geoid reference set in it? Perhaps even a manually set one.

What GPS display? What GPS head, what AP ?

 

[pvb]

Your ST50 GPS display should have an NMEA input; connect your GPS data to that and it'll be transmitted on the SeaTalk bus to your radar.

 

[SvenglishTommy]

Seatalk bus is bidirectional so 'In' and 'out' don't matter.

So I can connect an 'out' to an 'out'?

The autopilot is an Autohelm type 100 with an ST7000 control unit. The GPS is an ST50 plus dGPS, and it has no settings to adjust as it's just a mushroom - I'm pretty sure it's buggered. As pvb said, it does have an NMEA input, so I'll just give it NMEA from the Lowrance plotter.

What about the radar, anyone know how I get this in the chain, I guess it cant be chained as it only has one seatalk connection, can I just parallel wire this into the loop?

 

[AngusMcDoon]

So I can connect an 'out' to an 'out'?

The autopilot is an Autohelm type 100 with an ST7000 control unit. The GPS is an ST50 plus dGPS, and it has no settings to adjust as it's just a mushroom - I'm pretty sure it's buggered. As pvb said, it does have an NMEA input, so I'll just give it NMEA from the Lowrance plotter.

What about the radar, anyone know how I get this in the chain, I guess it cant be chained as it only has one seatalk connection, can I just parallel wire this into the loop?

With Seatalk it doesn't matter about number of connections and ins and outs - just connect them all together. Devices with 2 Seatalk connectors are connected inside anyway. The 2 holes is just convenience so you can daisy chain things together. The only thing to be aware of is that some larger devices (like autopilots) cannot take their power from the Seatalk connection as they take too much. They need a separate power supply as well.

 

[nimbusgb]

Seatalk has 3 wires. Red ( 12v ) the shield ( 0v ) and Yellow ( signal )

You can parallel seatalk devices on those 3 wires. The devices have a scheme where they wait for an open timeslot to put their info on the bus.


Your radar just happens to be at the end of one spur.

 

[SvenglishTommy]

Thanks guys, I just mashed everything up any old how and it all works - pretty neat.

I left out the red for the radar and autopilot connections as they have their own independent power.