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Author Topic:   NMEA-2000: Mixed Networks: Connector Problems
jimh posted 01-04-2007 12:54 AM ET (US)   Profile for jimh   Send Email to jimh  
At the fundamental level, the NMEA-2000 protocol is intended to permit networks to be easily constructed using devices from more than one vendor. The early implementation of NMEA-2000 has seen some vendors use connectors which are incompatible with the proposed standard connector.

One of the reasons offered for the use of non-standard connectors was apparently a rather high price for the official standard connector, which was available from only a single source. There has been some recent news that the single-source vendor (Molex) has reduced the price, and that more manufacturers will be moving to the standard connector.

At the moment, however, there seems to be two distinctly different connectors in use by the two manufacturers who seem to have introduced the first wave of NMEA-2000 devices, Lowrance and Evinrude.

Lowrance uses a plastic twist-lock connector and a plastic T-adapter which permits relatively easy connection and daisy-chaining of devices. This connector is referred to hereafter as the LowranceNet connector. You are probably familiar with it, if you have seen any of the Lowrance devices or visited their website.

Evinrude uses a 6-pin Deutsch connector for their NMEA-2000 network connector. The connectors are intended to plug into a hub, and they do not lend themselves to daisy-chaining like the LowranceNet connectors can do with the T-adpater.

If you want to use Lowrance gauges with an Evinrude motor there are two methods of building the network. In the first method, you use Evinrude's hubs and employ an adapter cable. In the second method you use all LowranceNet wiring devices. I briefly describe the two methods:

Evinrude Hub + LowranceNet

In this wiring topology, the network's main bus is constructed using the Bombardier Evinrude devices. (These are described in detail elsewhere.) At least one hub will be of the engine and power type. This hub connects the engine to the network and also connects the network to the batteries. Some circuitry in the hub manages the power on the network, taking a cue from the power in the engine. That is, the network powers up when the engine powers up. If the engine is off, the network is off. To connect LowranceNet devices, you must use an adapter cable. This cable has a 6-pin Deutsch connector on one end and a LowranceNet connector on the other. You plug the 6-pin Deutsch connector into the Bombardier hub, and the LowranceNet connector into the Lowrance device or into a Lowrance T-adapter to continue the network backbone onto more devices using the LowranceNet wiring.

All LowranceNet Wiring

In this wiring topology, you forego use of the Bombardier hubs entirely. Instead you use LowranceNet wiring for the network backbone and drop cables. To connect the engine to the network you use a different adapter cable. This one has a LowranceNet connector on one end, and on the other end a 4-pin Deutsch cable which plugs into the network connector under the cowling on the E-TEC engine. In this configuration, you have to provide power to the network backbone using the LowranceNet power connector. Consult the LowranceNet wiring practices for details.

The choice of which wiring system to use is influenced by what instruments you plan to use. If you want to use the I-Command Classic instruments, which have the traditional dial pointer type indicators (although they are not analogue gauges), you must have a Bombardier network hub. The I-Command Classic gauges are all wired with the 6-pin Deutsch connector. If you are using the Bombardier I-Command Digital gauges--which are almost identical to the Lowrance gauges--you might decide to use the all LowranceNet wiring.

Adapter Cable Required
No matter what wiring you choose, you will need to employ an adapter cable to connect the LowranceNet wiring devices to the E-TEC motor, either directly or to the Bombardier Hub. Again, a different adapter is need in each case.

I will dig up some part numbers and prices for the adapters to help clarify this.

All of the above is based on my first-hand, in person observation of all of the devices I have described, and upon the consultation of my local dealer, David Zammitt of Lockeman's Boat and Hardware. David is in the process of building a rather elaborate NMEA-2000 network to demonstrate all of the components used and many of the options available. Look for more information on Dave's demonstration masterpiece in the future.

Chuck Tribolet posted 01-04-2007 09:32 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
I think "Connector Solutions" would be a more appropriate
subject line than "Connector Problems".

Interesting that the motor has to be for the network to be
up. What happens when we have NMEA-2000 connections between
GPS and VHF (I know that that doesn't exist. Yet.) and we
send a VHF distress call with the engine off? Mmmmm.


jimh posted 01-04-2007 09:56 AM ET (US)     Profile for jimh  Send Email to jimh     
The ignition key just has to be in the ON or RUN position to power up the network using the Bombardier hub. For the LowranceNet appproach, more research into powering options is needed. Coming soon, as they say, or perhaps someone will have some experience to contribute.
davej14 posted 01-04-2007 08:03 PM ET (US)     Profile for davej14  Send Email to davej14     
All NMEA2000 networks must be powered. In the case of LowranceNet this can be done via dedicated power connections on a Lowrance accessory that is connected to the network or via a power adapter. Only one method should be used.

In my case, I wired the NMEA2000 power cable on the back of my LMS332c combination Sonar/GPS unit to the battery. This network power connection is a separate and distinct set of wires in addition to the battery connections which power the sonar and display. It is simply a pass through to the network. If the GPS/Sonar unit is turned off the network and all other active devices on the network remain powered.

As an alternative, power could be supplied to the network via a cable attached directly to one of the "T" connectors.

Be sure to install a switch for the network power in either case or your battery will be drained by the active devices on the network such as the GPS antenna or fuel flow sensor during periods of storage.

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