I'm installing a SeatalkNG network in my sailboat. It will connect a Raymarine e7d MFD, Raymarine p70, Raymarine X5, and Simrad RS35 VHF/AIS receiver to start.
The X5 came with 2 of the 5-way devices, and I've bought a 3rd (not realizing that it would come with 1, let alone 2). I have none of the blue backbone cables, but plenty of spur cables including a 5 meter one.
Is there a reason that I couldn't run the 5 meter spur cable between two 5-way devices and then connect the MFD and P70 to one of those 5 ways in my pedestal and connect the X5 and radio to the other down below?
The network would look like this:
5-Way A (in pedestal)
* blue terminator
* spur cable to 5-way B
* spur cable to e7d
* spur cable to p70
* blue terminator?
5-way B (below decks)
* blue terminator
* spur cable to 5-way A
* spur cable to X5 course computer
* spur cable to RS35 VHF
* blue terminator?
One issue is that I'd have 4 terminators in my network when I should only have 2. I know that the proper method would be to use a backbone wire between these two 5-ways, but don't understand what is going on electrically that makes this matter. I've read the Panbo articles on what Raymarine is doing with the 6th pin on the spur cables, but don't think that I'll be using that feature.
The other wiring option with what I've got is this one:
Single 5-way:
* blue terminator
* 5 meter spur cable to p70
* short spur cable between P70 and e7D (p70 allows daisy chaining)
* short spur cable to X5
* 5 meter spur cable to VHF
I don't really like this option because it puts my most important device (the MFD) behind a fairly unimportant one. That gives me more methods of failure.
Given the short total cable length (how much is that actually?) and only one device consuming power over the 2000 (STng) bus I'd say that using a spur cable won't be an issue.
However, 4 terminators surely will. Use two only, not four. One on each 5 way connector. Each terminator contains a 120 Ohm resistor.
No GPS?
I agree with Kees, one terminator on each 5-way. Then the 5 meter spur is your backbone and a perfectly good one, I'm pretty sure. Raymarine spur cables are very similar to regular N2K cables when you look close and the data doesn't know the difference.
Thanks, I'll give it a try. Glad to know that it should work, that was my guess.
Kees: The MFD is also a GPS. It has one built in, I don't require an external one too. It also has a built in sounder and handles the speed transducer, and my wind transducer (home built) is NEMA 0183 based.