Sea talk interfacing

[petery]

The Raymarine ST40 etc instruments I have bought come with a Sea-talk cable with a plug at one end and tinned wires at the other. The manuals suggest I buy a Sea-talk accessory to connect them up, but would a simple 'chocolate block' connector do the job - assuming I kept the elements out. Any advice would be welcome as I will be installing an integrated system - not stand alone.

 

[steve_cronin]

Yes and No.

Yes nmea data in most of it's facets is emitted from seatalk but you may find that SOG & COG are either missing or corrupted.

raytheon make no apologies for having a hybrid version which forces you to buy their interface box for total compatibility.

Steve Cronin

 

[davidwf]

Assuming you are sticking to a Seatalk system a chocolate block will work fine. If you want to integrate the Seatalk to NMEA then depending on what you are doing you may need a Seatalk to NMEA bridge.
However if all you are doing is passing GPS info to an Ratheon autopilot there will be no problem as the pilot has both NMEA and Seatalk inputs.

 

[Chris_Stannard]

If all of your instruments are Raytheon/Raymarine, you do not need to worry about NMEA. If you have a Sea Talk cabble with tinned ends you crimp on small spade female connectors. connect the red cable to the red seatalk connection on the back of the box, the yellow to the yellow and the black to the black.

The red cable is power and you only need a powwer input at one point, this is usually taken from the autopilot if fitted. If you want to power the instruments seperately to the autopilot then you must only connect the yellow and black from the autopilot as if you power both ends, in my experience, you will blow the fuses.

If you want to connect NMEA you either need the bridge, but if you have the multi instrument this does produce a limited number of NMEA sentences, and these are set out in the handbook. If you have not got a copy you can down load it from the Raymarine website, if memory serves, on the customer support page.

If you only need a number of short cables, to connect instruments that are mounted close together, I have some spares that I can send you or you can pick up if you are in Cowes. They will cost you a couple of quid for the RNLI and I will trust you to pay them.

E mail with your phone if you have any problems and I will do what I can to help

Chris Stannard

 

[jfkal]

Sad but true.

 

[brian_neale]

To be fair(ish) to Raymarine, some of their kit does produce NMEA output; specifically the GPS300 has both Seatalk and NMEA out, so that it will work with their integrated systems but also handle NMEA for a DSC radio and/or PC connection. I think that the GPS300 also bridges some Seatalk data to NMEA, but without the manual to hand, I cannot confirm this. One area in which Raymarine do excel is putting all their manuals, quick reference guides, etc, on their web site for free download. Pity more people do not do this (I think that Garmin do, Simrad do not).

The official Raymarine junction box for Seatalk is a piece of choc block in a plastic case...

 

[LadyInBed]

I was a bit Peed off that there was no NMEA o/p from the ST5000 fluxgate compass.

God - I wish it would stop raining!

 

[jfkal]

Sorry to disagree. Raymarine does only provide a few selected sentences on their NMEA ports and does not really indicate so. Took me some time to find that out. The junction box is not only choc but carries active logic which converts the remaining sentences at quite a cost ( Labelling their ports at the Autopilot NMEA is quite misleading since it is nothing more but a technical unidirectional RS232 with a limited set of NMEA sentences. Using NMEA as label however implies the full vocabulary which it is obviously not.
Other than that they make great equipment ))

 

[JerryHawkins]

Simrad manuals on-line

Simrad DO have manuals for most of their kit available for download from their US website (http://www.simradusa.com). The manuals are PDF (need Acrobat Reader) copies of the paper versions you get with the kit.

Cheers,

Jerry

 

[brian_neale]

Re: Simrad manuals on-line

Thanks for pointer to Simrad site - silly me, I went to their main site, which was less than helpful!

Re Raymarine "junction box" - I think that we are at cross-purposes here. There is a Raymarine NMEA-to-Seatalk convertor box, which costs a lot, and apparently has only limited functionality (i.e. limited NMEA sentence support). I was talking about the Seatalk junction box, purely electrical and not intelligent, which Raymarine supply (mine came with the radar, I think) and which allows you to connect the Seatalk cable which came with the radar and which is terminated with pins, not a plug, to the Seatalk cable running to the other instruments. Because Seatalk also carries power to the instruments, and the radar does not put power on to the bus, they supply, literally, a plastic box containing a piece of choc block to connect both power and signal cables. My only point here is that the you can indeed use choc block for joining Seatalk cables. Just match the colours.

Taking a quick look at the GPS300 manual, it appears that it does bridge some Seatalk data, but mainly position and satellite data; things like SOG and depth do not appear to carry across. Fortunately, I only need position output for the VHF radio, having been brain-washed by Raymarine into a "single manufacturer" strategy.

I did find a web site some time back with the results of someone reverse engineering the Seatalk data stream, which could form the basis of a PC-based programme to read the data, but I no longer have the URL.