NMEA2000 connection question

Doc O Rock

Doc O Rock

Active Member
Mar 23, 2016
448
Belle Maer Harbor, North Channel Yacht Club
Boat Info
1999 380 Sundancer
Engines
twin 7.4 Merc
I am installing a pair of Fox Gateways on my 99 380. In the engine space, I have a Nema splice on the bulkhead from a previous installation. Can I install my Nmea T's in the splice connector?
 

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Doc O Rock said:
I am installing a pair of Fox Gateways on my 99 380. In the engine space, I have a Nema splice on the bulkhead from a previous installation. Can I install my Nmea T's in the splice connector?
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Is that your backbone cable? If yes, the just put the T‘s in between.

Fox gateways are great btw.
 
Golfman25 said:
Is that your backbone cable? If yes, the just put the T‘s in between.

Fox gateways are great btw.
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I think it's an extension of the Nmea going to the port-side fuel flow meter. I've read a lot of the theory of NMEA but other than paying my electronic guy to hook stuff up and watching over his shoulder, this will be the first start-to-finish job myself. What could go wrong?
 
Doc O Rock said:
I think it's an extension of the Nmea going to the port-side fuel flow meter. I've read a lot of the theory of NMEA but other than paying my electronic guy to hook stuff up and watching over his shoulder, this will be the first start-to-finish job myself. What could go wrong?
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So trace that back to the T where it connects. I don’t think you can jump into an extension like that. I think the connections are different sizes.

Mine for example. I have the main backbone cable terminate with T connectors. The Ts feed to the fox marines. The backbone then goes up behind the helm where it gets power and more Ts feed the gps and such. Then I can either terminate it there or run a backbone into the cabin.
 
All NMEA 2000 connections are the same (DeviceNet) connectors. There is no difference between the connectors on the backbone than on the branch connections. Actually branch lines are the same as the backbone. Maretron does make a dedicated backbone cable which is a heaver insulation.

But as @Golfman25 says, you cannot connect multiple devices to a branch; if you do and it works you're lucky. There is a "multi-port box" that is a special device which allows a branch to have more than one device on the branch but they are a bit on the pricey side.
Every device must tap into the backbone uniquely.
 
ttmott said:
All NMEA 2000 connections are the same (DeviceNet) connectors. There is no difference between the connectors on the backbone than on the branch connections. Actually branch lines are the same as the backbone. Maretron does make a dedicated backbone cable which is a heaver insulation.

But as @Golfman25 says, you cannot connect multiple devices to a branch; if you do and it works you're lucky. There is a "multi-port box" that is a special device which allows a branch to have more than one device on the branch but they are a bit on the pricey side.
Every device must tap into the backbone uniquely.
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I think I might fish a separate drop down to the engine room.
 
As a suggestion, extend your backbone to the engine room rather than a drop cable. Then you can have as many devices connected to the network as you desire in the engine room or anywhere the backbone is routed.
If you are anything like me, your system will grow over time as the capability of that network is better understood.
 
What ttmott said. You’re going to need two connections for the gateways.

in fact what you can probably do is use the wires you have. Find out where the current one terminates. Change it from a drop to a backbone. Then add a few T‘s in the engine room to connect everything you have there.
 
So I fished an extension to the engine room and made up a backbone down there. I think it will be useful to have one down there in the future. I powered up and the mfd opened to configure the Engine data. Now I need a dedicated display in my line of site for engine data and just replace the old gauges.
 

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ttmott said:
As a suggestion, extend your backbone to the engine room rather than a drop cable. Then you can have as many devices connected to the network as you desire in the engine room or anywhere the backbone is routed.
If you are anything like me, your system will grow over time as the capability of that network is better understood.
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This is exactly what it did.
 
Doc O Rock said:
So I replaced my Garmin GMI 10 with a Garmin GMI 20 and now I have what I want in a compact display right in front of me.
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I have two of them, one for each engine. The only thing I don't like about them are they only display RPM in increments of 50 RPM. Their MFD's have the option to display RPM without rounding, I wish they would add that to the GMI 20.
 
SKybolt said:
I have two of them, one for each engine. The only thing I don't like about them are they only display RPM in increments of 50 RPM. Their MFD's have the option to display RPM without rounding, I wish they would add that to the GMI 20.
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I also had GMI20's in my other boat and found their displays to be "canned"; which is great for most. Since, I've moved over to the Maretron DSM displays and I've found their flexibility to not only display more and different data but also to customize the data to best fit the boat's needs.
 
ttmott said:
I also had GMI20's in my other boat and found their displays to be "canned"; which is great for most. Since, I've moved over to the Maretron DSM displays and I've found their flexibility to not only display more and different data but also to customize the data to best fit the boat's needs.
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Yeah, same price and much more flexibility. I like the look and feel of the GMI 20 much better then the 410. But to your point, much more flexibility in the DSM 410.
 
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