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A Common Language – Electronics

Let your systems talk things over.

Cooperation among manufacturers could soon make it easy to “plug and play” different brands and types of marine electronics on a central nervous system. Shown here is a proprietary network, the Mercury SmartCraft, which consolidates navigation and engine monitoring functions on a single color screen, middle.

Imagine livebait fishing, and being able to simultaneously monitor two temperature sending devices—surface water temp and temp in the livewell—on one screen, while also seeing how deep the water is under the boat.

Enter NMEA 2000.

Chances are you’ve heard of the acronym. It stands for National Marine Electronics Association, formed 50 years ago by a consortium of marine electronics manufacturers. Industry types pronounce it “Nee-Muh.”

In 1980, NMEA developed the first standards that determine how two or more electronic devices “talk” to one another. The protocol was termed NMEA 0180. At the time, one of its primary functions was to allow a loran C receiver to converse with an autopilot, telling the autopilot where to steer the boat. (Like you telling your buddy which way to go—except he actually listens.) Over the years, a new version—NMEA 0183—became the worldwide standard.

Different brands of electronics could now talk in a common language. For example, the standards developed in the early 1980s allowed a Furuno loran to be interfaced with a Robertson (now Simrad) autopilot: You enter a waypoint into your loran, and the autopilot could follow navigation data transmitted by the loran.

Neat stuff, but there was a shortfall of sorts. A NMEA 0183-compliant instrument could give and receive data commands to only one other instrument. A third or fourth instrument could be interfaced with the network, but only on a “listen” basis—unable to “talk back” to relay information.

Thanks to advances in computing technology, and the efforts of NMEA and the U.S. Coast Guard, there’s now a new set of standards, much broader in scope.

In computer lingo, NMEA 2000 is a bus network designed specifically for boats. Think of NMEA 2000 as a community of electronic devices on your boat, all hooked together to a common bus through which they can transfer data. “We have established a universal open standard,” said Beth Kahr, president of NMEA, located in Severna Park, MD. “Any NMEA 2000-certified device can talk and listen to any other NMEA 2000-compliant device.”

In late 2000, the new NMEA 2000 standards (technically called “2000R”) were approved by NMEA members. Electronics manufacturers began to design GPS units, chartplotters, radars and other systems to use NMEA 2000. Not all boat and electronics manufacturers have upgraded to it, but most are working on ways to do so, while maintaining proprietary systems.

Mercury Marine developed its own bus system in 1999, called SmartCraft. Scott Graves, Mercury product manager for digital controls, said, “SmartCraft is based on a communication systems called Control Area Network, or CAN, and CAN is the same data communication system that the NMEA has chosen for NMEA 2000.”

Mercury’s current SmartCraft system was originally designed to facilitate digital communication between the engine(s) and the boat’s instrumentation, and it is compatible with most GPS units via the NMEA 0183 protocol. “This interface allowed Mercury to be the first to provide fuel management and fuel-to-waypoint information to the boater via their SmartCraft gauges,” Graves said.

An electronics manufacturer is eligible for NMEA 2000 compliance after that manufacturer self-certifies its product to ensure it will communicate successfully on the NMEA 2000 bus. The Mercury SmartCraft system was developed and released several years in advance of NMEA 2000, and has the ability to manage highly complex messages, such as those used to manage the Digital Throttle and Shift (DTS) system, standard on Mercury’s new Verado engines.

“Mercury is currently working on ways to interact with NMEA 2000 devices, but at the present time, Mercury has not released an interface to the protocol,” said Graves, adding that, “Mercury does, however, foresee the potential to develop a gateway product between SmartCraft and NMEA 2000.”

Fuel flow and oil pressure for port and starboard engines are shown.

Multi-tasking is the hallmark of NMEA 2000: Up to 50 electronic devices can talk, listen, and transfer data back and forth to each other.

Another innovation, Kahr of NMEA explained, is “true plug-and-play capability.” This means you can add or remove equipment without reconfiguring your network. Manufacturers using NMEA 2000 build on a standardized cabling and connector system, enabling you to plug a variety of products to the network, much like you would through the USB cable on your home computer.

There’s also an inherent safety benefit. Many engine manufacturers are currently developing engine management systems that, with a simple plug-and-play connection, can send data relating to tachometer, voltage, oil pressure, fuel level, engine temperature and cooling water temperature to an engine management program that, using NMEA 2000 protocol, can override the operator’s instructions and shut down the engine, avoiding a potentially dangerous situation.

The NMEA 2000 standard is an improvement over the older 0183 standard, but boaters should be prepared for the fact that many older NMEA 0183 instruments may not communicate with NMEA 2000 electronic instruments.

At the Miami Boat Show in February, industry giant Furuno had its new NavNet vx2 system on display. I asked Jeff Kauzlaric, Furuno communications manager, how they had integrated NMEA 2000 into the newest NavNet system, and was surprised by his answer.

“NMEA 2000 uses a data bus and not a video bus,” he explained, “and just like Raymarine, Garmin, Lowrance and many of the other marine electronics manufacturers, we all support NMEA 2000; it’s just that NMEA 2000 does not have the bandwidth we and many of the other manufacturers need to transfer video (i.e. cha
rts, radar, bottom contours, etc.).” For video transfer, Furuno and the other electronics manufacturers use ethernet cables.

While NMEA 2000 is a giant step forward in the way electronic instruments can share data, it is not yet a cure-all for the boater as it will not let electronic instruments share all of the information on their displays. For more detailed information, visit www.nmea.org.

FS

  • Rick

    NMEA 2000 For Older Boats. According to the company's website, the RS11 from Noland Engineering takes analog data from existing gauges and tachometers and converts it to NMEA 2000 (and J-1939) compatible data for use by a user supplied NMEA 2000 display / data bus. It has a very inexpensive price (a little over $200) and looks like a great aftermarket way for adding engine monitoring capability for older (pre NMEA 2000) boats or for collecting and sending analog gauge information to a new NMEA 2000 display installed at a second location on the boat. The company's website (www.nolandeng.com) says that one RS11 supports either a single or dual engine configuration. Does anyone have any personal experience with this product?