Raymarine sea talk and power

[jimmyk]

Hello. I have a raymarine st4000 autohelm and an St 30 wind instrument. Does the wind instrument have to have its own power source or can the St 400 power it through the sea talk cable. Thanks

 

[prv]

I would have expected the autopilot to supply power to the Seatalk bus, most of them do. However, the manual for the ST4000 claims that it must not be used this way!

However, I can't see any reason not to apply power to the bus, via a small fuse (say 2amps), from the supply that must exist at the back of the autopilot. Just not through the pilot itself.

Pete

 

[jimmyk]

Thanks for that. I wanted them powered separately but if I put one on the other comes on too. They are connected by seatalk so that the wind info goes to the autopilot

 

[earlybird]

I would have expected the autopilot to supply power to the Seatalk bus, most of them do. However, the manual for the ST4000 claims that it must not be used this way!

However, I can't see any reason not to apply power to the bus, via a small fuse (say 2amps), from the supply that must exist at the back of the autopilot. Just not through the pilot itself.

Pete

My manual specifically says that the seatalk power line, and hence other instruments, can be supplied via the ST4000 instrument supply, but not vice-versa, which seems logical.
A risk of installing separate feeds to the Tiller pilot and other instruments, in addition to connecting them by seatalk cables is that the autopilot might appear to be powered up, but it won't function if it's main supply has not been switched on.
Perhaps this could be avoided by cutting the red Seatalk conductor, but separate supplies seem unnecessary anyway IMHO.

 

[jimmyk]

My manual specifically says that the seatalk power line, and hence other instruments, can be supplied via the ST4000 instrument supply, but not vice-versa, which seems logical.
A risk of installing separate feeds to the Tiller pilot and other instruments, in addition to connecting them by seatalk cables is that the autopilot might appear to be powered up, but it won't function if it's main supply has not been switched on.
Perhaps this could be avoided by cutting the red Seatalk conductor, but separate supplies seem unnecessary anyway IMHO.

I think you're right. I'll power the autohelm only. Save me a switch I supose

 

[prv]

My manual specifically says that the seatalk power line, and hence other instruments, can be supplied via the ST4000 instrument supply, but not vice-versa, which seems logical.

How odd. The manual I found on the Raymarine website definitely said not to power the bus from the autopilot, "for safety reasons".

Pete

 

[nigelmercier]

How odd. The manual I found on the Raymarine website definitely said not to power the bus from the autopilot, "for safety reasons".

Possibly because the AP is fed via a big fuse, and the SeaTalk bus needs a lower rating.

 

[earlybird]

Just compared manuals for the ST4000plus+, (mine, which is about 8/9 yrs old) and ST4000, older version, from website.
The former definitely says that other instruments can receive power via the ST4000+, for which a 12 amp fuse is specified.
The latter does indeed carry the warning that other instruments should not be so powered. A 5 amp fuse is specified, and the Seatalk connection is shown as yellow and ground only, not red.
Seems that Raymarine may have changed things slightly, if only their minds!
Further thought; I suppose there's not much practical difference in wire protection terms between a 5 amp and a 12 amp fuse.

 

[prv]

Possibly because the AP is fed via a big fuse, and the SeaTalk bus needs a lower rating.

That's what I assumed, though the manual doesn't say.

My S1 autopilot powers the seatalk bus, and it has a 2-amp blade fuse under the wiring cover that protects the output.

Not hard to put a 2-amp fuse in a holder inline with the seatalk power output, either from the ST4000 itself if it has such an output, or piggybacked off its input as I first suggested.

Pete