Raymarine Seatalk Power Question

[jwrhind]

Hi

I'm confused about the Seatalk bus power distribution arrangements.

From what I read, the Seatalk bus carries power, but at some unspecified current capability.

I'm looking at a C-series display, with radome and a ST4000 pilot and wondering what power supplies exactly are needed. To date, my understanding has been that the C-series needs a power feed and the ST4000 a power feed and that both can come from separate CBs.

But how does this relate to power distribution on Seatalk? With one of the CBs off I wonder whether (a) the remaining CB will try to provide power for both, or (b) there's current limiting on the Seatalk bus that simply will stop the unpowered unit working.

Curiously, the ST4000 manual says that it needs its own power feed and is capable of powering other Seatalk instruments.

Can anyone explain this? Is it better to power the whole lot off one CB?
It seems to me sensible that the nav kit and pilot should have separate CBs since the latter is more likely to trip.

Thanks
JR

 

[Graham_Wright]

You could ask Raymarine.
The warning they sounded to me was that, if a chain were too long, it would be necessary to feed a ring at both ends. Sounds like you just poke power in wherever it is necessary/feasible.

 

[pvb]

Seatalk....

As I understand it, Seatalk is the system for transmitting information between different Raymarine units. It carries some limited power (for example to power the GPS antenna) but is not intended to provide the higher currents needed for units which normally require their own power supplies. So, in your example, if the autopilot's main power input is switched off, it won't work the autopilot using the power in the Seatalk connection.

I don't see a problem powering the radar/plotter and the autopilot off separate breakers. Incidentally, I've never had the autopilot breaker trip.

You can download a C-series owner manual or installation guide from the Raymarine website, and they contain lots of information on how to integrate the various systems. I've just installed a C120 with radar and rate gyro, and it is very good.

 

[Ships_Cat]

Not sure if I totally understand your question but -

The instruments on the Seatalk bus use little power (much less than an amp even if you have a whole bunch of them) but obviously the pilot's drive requires more (don't know about the 4000 but the linear ones typically 2-3 amps).

So you have to provide power to the drive, normally via the course computer/controller, but typically on the course computer/controller's Seatalk cable connection it will also supply the 12 volts needed by the instruments (log, etc), if any, on the cable. I am not sure exactly how it works with the 4000 as I have only used the bigger linear drive ones but the theme should be the same.

What you can do if wanted, is fit it as described above so that the instruments are powered from the pilot but also break into the Seatalk cable to the instruments somewhere (anywhere) and put an independant 12 v supply on the power line in the Seatalk cable with its own breaker so that you end up with power from the course computer on the Seatalk cable and the independant supply as well, both live. This means that should you have a course computer/controller failure you still have all your instruments alive on the independant supply.

I have not used a C series display but I would be quite confident that it will also put 12 v onto the Seatalk cable for the instruments on the cable but it will need its own power supply in just the same way as the pilot - it won't run off (or even try to run off) the power on the Seatalk cable.

John

 

[AlexL]

John
Raymarines website has a very good 'ask raymarine' facility. I am in the middle of installing C80, Radar and S1G smartpilot and they have got back to me same day with most of my questions.

The C80 and autopilots have their own supply - do not underestimate the current capability required. My C80, 2kW radome setup has a 15A fuse and the SmartPilot a 25A fuse - both supplied with 6mm^2 cable. I have actually put the C80 and pilot on a single breaker - with separate blade fuses for each instrument (mainly to protect the cable) in the cockpit locker - accessible from the helm. I'm pretty sure that you won't accidentally end up trying to power the C80 and autpilot from the seatalk bus if you turn one on but not the other, or the instruments on, but not the pilot or display, but check this with rayamarine - I would also be interested in the answer.

As I have said I have the main supplys to the C80 and S1G on one breaker, and they also supply the seatalk power to the controller, and the GPS. My other instruments (Wind, speed, depth) are simrad and on a different breaker.
There is a circuit diagram in the C80 installation manual (or the S1G smart pilot manual?) which shows how to power the instruments from a separate breaker, if required. With my setup - (which was driven by necessity because of the different types of instrument) - I still keep wind / speed / depth if the radar / C80 / pilot breaker blows out.

 

[davidwf]

The Autopilots do output power on the seatalk bus and can be powered via that bus as well. However as the autopilots draw a large amount of power it is recommended by Raymarine that they are the first in the power/ seatalk train so you can then use normal low amperage seatalk cables from the autopilot to the instruments. I also suspect that Raymarine would prefer you not to draw 5 ams or so via the instruments.

If I remember right the installtion instructions are very clear on how ypu should wire the AP and instruments.

 

[pvb]

No, the C-series displays do provide power...

The C-series displays do provide power to the Seatalk bus. I've just installed one, and the Raymarine installation manual clearly explains this. You can download a copy here - page 9 of the manual has a diagram.

 

[snowleopard]

my hydraulic autopilot has to have power cabling rated for 18A. no way you will get that throught he seatalk bus. radar is also a high current user which would need its own power. the manual says you can daisy-chain up to 16 instruments together but you may need to feed 12v in at both ends of the bus if working near the limit. they advise fitting a 5A fuse to the bus supply. the power input can come direct from the ship's supply or via an autopilot.

 

[jfkal]

Simple rule of thumb. Whatever device which comes with an extra power supply cable (RADAR, CHARTPLOTTER etc) other then the Seatalk plug (with yellow datacable removed) WILL need that power to function. All other instruments are happy with whatever Seatalk provides (SEATALK consists of 12V DC red, bare (or black) and yellow data). With too many Seatalk instruments chained up Raymarine recommends to feed 12 V into both ends of then Seatalk bus.

 

[jwrhind]

Quote from Raymarine ...

<quote>
In SeaTalk network installations containing other power devices in addition to the GPS sensor (e.g. ST40, 50, 60, 80, 290 instruments, Autopilot controllers, etc.) you should NOT tie the red wire on the C-Series SeaTalk pigtail to the RS125 or overall SeaTalk network.

The C-Series display outputs 12V DC on the red wire. While there is enough current supplied to power a GPS sensor alone, it can not provide enough current to drive any more devices than that.

Leaving the red lead attached in this scenario can lead to instances where instruments, pilot controllers, and other SeaTalk devices will power on with insufficient current when the C-Series in energized.

This condition can cause the SeaTalk data bus to crash between all of the connected devices.

Installations with multiple powered SeaTalk devices are normally supplied from an autopilot course computer, dedicated SeaTalk network power feed or other heavy-duty source.
</quote>