Raymarine ST1 + STng instruments - best (or at least a) solution?

stranded

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Currently I have:

ST60 depth connected by ST1 > STng adapter cable to i60 wind;

i60 wind connected by STng > ST1 adapter cable to ST60 speed;

ST60 speed connected by STng > ST1 adapter cable to 5 socket Convertor;

Convertor connected by (thicker - is this relevant?) black and white spur cable to C125 MFD STng socket

The other Convertor connections are occupied by 2 x STng backbone + black and red power, so it is full.

This setup has worked just fine for a few years. Now the ST60 speed display head has died, so I have bought an i50. Not yet tried fitting. I was going to order a selection of bits so I could suck it and see - until I saw the price of a single 400mm STng spur cable (£34.95!) so more focussed now on getting it right first time.

So the most obvious place to start is simply to replace the ST1 > STng adapter from the speed to Convertor with an STng cable.

But would this work?

Shouldn’t the individual STng instruments be on their own spur cable?

If so, could I leave the ST60 depth and i60 wind as a group, connected to the Convertor as the whole group is now, and add the i50 speed to the backbone as an individual spur? Would they still all communicate?

Or put both the STng instruments on individual spurs and connect the ST1 depth to the Convertor? Communication with it would be less important as I don’t think any other instruments use the depth info (but I may be being dim)

Grateful for suggestions as to the most economical workable (not bothered about elegant) solution.

Thank you.
 
I don't entirely understand your description of how everything's connected, but I hope this explanation is helpful.

SeaTalkNG is mostly just NMEA2000 with different connectors.

An NMEA2000 network always has a backbone, like this:

iaCr3xI.jpeg
The backbone is indicated by the dotted red line in the diagram; it has terminators at each end.​

So the SeatTalkNG part of your network should be the same.

T-pieces look like this:

nDGVtjt.jpeg

This is simply three (??) T's stuck together:

OckLtZ2.jpeg
Effectively it is a "mini" or "all in one" backbone - I think they should either have a terminator at each end (the blue connectors) or these can be daisy-chained , with a cable between the stern blue connector of one and the bow blue connector of the next.​

So superficially I think this answer to your question is that, yes, each SeatTalkNG instrument should have its own drop cable (possibly Raymarine calls these "spur" cables).

However, the difference between NMEA2000 and SeaTalkNG, apart from the physical connectors, is that SeaTalkNG has an additional wire that carries Seatalk1 and this may be what you're seeing here.

If a SeaTalkNG connector is a different colour then that has significance - e.g. the SeaTalk1 to SeaTalkNG converter has a yellow connector.

With NMEA2000 / SeaTalkNG you always, always, always need to be cognisant of your backbone - you need to know where it is, where the start and end are (terminators) and always , as you say, have each device on its own T and drop cable.

I'm afraid I don't know anything about ST1 over STng. I think some of the Raymarine devices contain a microcontroller to convert SeaTalk1 sentences into NMEAN200 ones and send them over the SeaTalkNG network. But presumably that additional wire is sometimes used for something? @PaulRainbow will surely know.

Also, some of Raymarine's instruments do piggybacking - one sends data to the next independently of the SeaTalkNG network. I think they have discontinued this.

I'd never buy an i50 or i60 instrument - the i70 is a thing of beauty, far superior and seems to be only about £100 or £200 more? It's far more flexible - it can display, speed, depth, wind, a combination of them, AIS vessels or any other information that's on the SeaTalkNG network. The night mode is excellent.
 
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Yes. The trouble is, I’ve got two x ST1 + 1 STng instrument displays daisy chained in a discrete cluster running on a spur (drop cable) to the ST1>STng Convertor via an ST1>STng adapter cable from the ST60 Speed display at one end of the daisy chain. (The transducers connect directly to their appropriate display heads). The book learning doesn’t seem to recognise that configuration, but it works.

So the simple version of my question is, does anybody understand why it does work, and if I simply replace the ST60 Speed (ST1) with an i50 Speed (STng) and the ST1>STng adapter cable with a straightforward STng>STng spur cable in the same discrete cluster configuration, might that also work.
 
Currently I have:

ST60 depth connected by ST1 > STng adapter cable to i60 wind;

i60 wind connected by STng > ST1 adapter cable to ST60 speed;

ST60 speed connected by STng > ST1 adapter cable to 5 socket Convertor;

Convertor connected by (thicker - is this relevant?) black and white spur cable to C125 MFD STng socket

The other Convertor connections are occupied by 2 x STng backbone + black and red power, so it is full.

This setup has worked just fine for a few years. Now the ST60 speed display head has died, so I have bought an i50. Not yet tried fitting. I was going to order a selection of bits so I could suck it and see - until I saw the price of a single 400mm STng spur cable (£34.95!) so more focussed now on getting it right first time.
Connect the i50 to the i60
The i60 to the converter
The st60 depth to the yellow socket on the converter
 
Fabulous, thanks Paul. Just one 35 quid 400mm cable then!
On second thoughts;

Connect the i50 to the i60
i60 to the ST60 depth
ST60 depth to the converter

You should have all of those cables ?

You can daisy chain an i60 wind, i50 speed and i50 depth, then use a converter cable to go from the last i50 display to an ST60 display. The ST60 can then connect to the converter.
 
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