TM Pub. 988-0154-173 NMEA 2000® Networks General Information The NMEA 2000 Network DeviceNet is the communication bus standard developed by the National Marine Electronics Association (NMEA) for use in boats. Lowrance has introduced a line of products that can communicate over a NMEA 2000 network, helping you get the most out of this technology. This instruction sheet will show how a NMEA 2000 network is created, configured and installed. Read the next few pages to become familiar with some of the following terms: NMEA 2000 Network/LowranceNET, NMEA 2000 Bus/Network Bus, Network Backbone, Network Nodes and Linear Architecture. Setup and Installation of NMEA 2000® Network or LowranceNETTM A NMEA 2000 network is a communications link between two or more devices that transfer NMEA 2000 information. LowranceNET is the NMEA 2000 networking system developed by Lowrance Electronics. A NMEA 2000 network functions like the phone wiring in a house. If, for example, you pick up a phone in the living room you will be able to hear the conversation someone is having on a phone in the bedroom. In similar fashion, a NMEA 2000 network allows multiple display units to receive data from a GPS antenna or multiple sonar units to receive messages sent by a temperature sensor. A NMEA 2000 network gives you the flexibility to view engine diagnostics and fuel level data on digital gauges or display units located anywhere on your boat. If you have a Lowrance display unit with a LGC-3000 GPS module installed, you have a NMEA 2000 network. The connectors and cables that came with your LGC-3000 function as a dedicated NMEA 2000 network, passing GPS data along the network to the GPS display unit. This is a simple form of a NMEA 2000 network. On the other end of the scale is a large network bus. You can easily expand a network bus by adding multiple NMEA 2000 devices, even adding the same type of device more than once. The network could share information with a sonar-GPS combo unit mounted in the dash, a sonar-only unit mounted at the stern and another display unit mounted on the bow. In that scenario, all three dis1 play units attached to the bus would have access to information from every sensor attached to the network. That is the advantage of a NMEA 2000 network. WARNING: The network MUST be installed in an area where it WILL NOT be submerged in standing water during normal operation of your vessel. NOTE: We recommend applying dielectric grease to all NMEA 2000 backbone and device connections. This will prevent moisture from corroding the connector terminals. Before connecting a T connector to another T connector or a NMEA 2000 device, apply a small amount of dielectric grease on the pin connectors of both male and female connectors. Every display unit, gauge or sensor attached to the network can communicate with all other devices on the network. Location, speed and temperature, however, are not the only kinds of information that can be shared. Fuel Remaining data along with engine information like oil pressure and fuel efficiency are among a large number of data options that may be shared on the network. NOTE: Full Sonar Chart returns CANNOT be transmitted on a NMEA 2000 network, because they take too much bandwidth for the network. Every sonar display unit requires its own transducer. If, however, you have a sonar display unit (with sonar bottom lock) connected to the NMEA bus, it will share the digital depth with all display units on the network. NMEA 2000 Bus or Network Bus Technically, any physical cable used to transfer network information is a network bus, but in our documentation we use this term to refer to the standard manufacturer installation appearing in new boats. This network bus is an operational network cable, connected to a power supply and properly terminated, that will run the length of your boat. It will provide access to network nodes at various locations on the boat. 2 (Connection for backbone) Sides of T (Connection for devices) Bottom of T This T connector allows you to add a device to your NMEA 2000 bus creating a network node. Network Backbone and Network Nodes A network bus backbone consists of network cabling, terminators and T connectors. Network nodes are made by fitting T-shaped connectors into the backbone (using the sockets on the sides) and attaching any network device to the bottom of the T. Double T connector Staying with the previous phone wiring example, T connectors on the backbone are the equivalent of phone jacks spread throughout a house. To pick up a phone and be able to hear a conversation from another phone in the house, both phones have to be connected to the main phone line. In similar fashion, only sensors and display units plugged into the NMEA network can share information. The network backbone is like the phone wiring that runs throughout a home. It connects the network nodes, allowing them to communicate across the network. Connections found in the middle of the bus could have T connectors or backbone network cable plugged into one or both sides. Connec3 tions at the end of a network will have the backbone cable plugged into one side and a terminator plugged into the other, as shown in the following figure. Terminator at the end of the backbone (bus) Cap for unused connector Double T connector Backbone cable (to rest of bus) Cable from sensor or display unit NMEA 2000 network node located at the end of a NMEA 2000 backbone. NOTE: If you have a double T Connector on your network that is not attached to a device, you must cap the unused connector with a NMEA 2000 cap. This will protect the pin connectors from corrosion. The NMEA 2000 cap looks like a terminator, but has "Cap" stamped into the connector housing. All T connectors on your network probably will be connected to a device. If you want to add another node to a working network, add another T connector. T connectors may be purchased from LEI (ordering information appears on the back page of this booklet). If you are adding a Lowrance or LEI NMEA 2000 sensor, it will come with its own T connector. Linear Architecture NMEA 2000 networks are constructed using a linear pattern. It is important linear architecture is maintained when the network is modified or a node is added to the network. Linear architecture refers to way the network's nodes are connected to the network backbone. Note that every T connector has two female sockets and one male socket. This means you could connect it in two different ways. Using linear construction, the T connectors will be connected side by side, leaving the bottom of the T available for connection to a display unit or NMEA 2000 device, like the "Correct installation" figure on the next page. A network built following a linear construction is easier to maintain and expand. 4 It also allows you to ensure the two terminators are at the ends of the backbone. If your installation does not follow a linear architecture, the network may not function. Backbone (Network bus) This network bus has a cluster of single and double T connectors and is terminated on both ends. It is connected to a display unit and four NMEA 2000 devices. You could use the recommended installation, plugging the sensor or display unit into the bottom of the T and the backbone cable into the side of the T. You also could plug the sensor or display unit into the side of the T and the backbone connection into the bottom of the T. The sockets would allow you to make that connection, but you would lose linear construction. Both installations are detailed in the following figures. Correct installation Sonar or GPS display unit Incorrect installation Sonar or GPS display unit LGC3000 EP-35 temp sensor EP-35 temp sensor LGC3000 Two possible network designs. The design on the left maintains a linear architecture while the one on the right does not. You should always maintain linear architecture when building a NMEA 2000 network. Both network designs in these images contain the same set of components. Both networks are terminated and all of the connectors are able 5 to be connected to one another, but the installation on the left comes to a clear end with terminators on each end of the backbone. The nonlinear installation on the right has no clear end, increasing the chance of an installation error. It also makes network expansion more difficult and could even prevent the network from functioning. Always maintain linear architecture when modifying your network. Make sure display units or sensors are attached to the bottom of the T. Attach the sides of the T to backbone extension cables, terminators or other T connectors ­ nothing else. All network examples in this document show networks built with a linear architecture. Adding a Network Node You can add a node to any existing connection, anywhere along the network backbone. This connection could be between a T connector and a terminator, between two T connectors, between a T connector and a backbone extension cable or between two extension cables. Wherever you want to add the new node, separate the sockets of the existing connection and install the T connector between them. Use T-connector or double T connector to add device to bus (maintaining linear architecture) Backbone cable to rest of bus Attach terminator at end of bus Existing network node Devices connect to double T connector In this example, a new device is added to the NMEA 2000 bus by installing a T connector between a T connector and a terminator at the end of the backbone (network bus). If you want to add a node at the end of the backbone (network bus) remove the terminator from the last connector, like the figure above. Install the new T connector and attach the terminator to the side of the connector. 6 Adding an Extension Cable LEI provides LowranceNET extension cables in various lengths, giving you the flexibility to install T connectors at desired locations on your boat. Every extension cable has a male connector on one end and a female connector on the other, allowing you to insert it anywhere on the network where there is an existing connection. You, for example, could have a cluster of T connectors at the bow of your boat with a 15' extension cable attached to the last T on the cluster. You could run the 15' extension cable to your boat's helm, where another cluster of T connectors could be installed. Just like the first cluster of T connectors, the last T connector on the cluster at the console could be connected to another extension cable running to the stern of the boat, where another cluster of T connectors could be installed. To ensure communication, make sure your network backbone to less than 300 feet (100 meters) long. LowranceNET Node Kit for a NMEA 2000 network. Includes a 2 foot extension cable, T connector, 120-ohm male terminator and 120-ohm female terminator. You can also attach an extension cable between a device on the network and its connection point at the bottom of the T connector. That would allow you to position the device right where you want it. You, however, should never have more than 18' (about 6 meters) of cable between a device and its T connector. Building a LowranceNET NMEA 2000 Network In 2005, boat manufacturers (Original Equipment Manufacturers -- OEM) began installing NMEA 2000 networks as standard equipment on new boats. If your boat does not have an OEM-installed NMEA 2000 network, you will have to install your own or take it to a qualified NMEA 2000 technician to have one installed for you. 7 Power Connections Your unit comes with a power/data cable that splits into three branches, each with several exposed wires. The thicker two-wire cable (red and black) is the power supply for your display unit. This cable has no label. The branch with three wires (red, black and shield) is the power cable for a NMEA 2000 network. It is labeled "NMEA 2000 POWER." The branch with 5 wires (blue, yellow, orange, green and shield) is a data cable, labeled "RS-232 COMM." It supports two serial communication ports. These allow your unit to exchange NMEA 0183 data with another device, such as an autopilot, DSC marine radio or computer. Display unit power wires: red and black To unit NMEA 2000 power wires: red, black and shield Data cable wires: blue, yellow, orange, green and shield The Power/Data cable for this unit. NOTE: There are two basic power connection options, which are shown in the following two diagrams. Read the following instructions carefully to determine which power connection applies to your unit. Depending on your configuration, you may not use all of these wires. Caution: All of the wires in the power/data cable have bare ends for easier installation. The bare ends on any unused wires could cause an electrical short if left exposed. To prevent this, cover the individual wire ends ­ either by capping them with wire nuts, wrapping them with electrical tape or both. (You should cut off th ...