Furuno NMEA 2000 Installation Guide

1. NMEA 2000 General Overview

Key Points:

• Network Power: 9-16V, isolated from other circuits.
• Maximum Backbone Length: 100m with micro/mini(light) / 200m with mid(heavy) cable
• Maximum Number of Devices per Backbone: 50 ea.
• Maximum Drop Length per Drop: 6m.
• Maximum Total Drop length per Backbone: 78m.
• Maximum Power Capacity per Segment: 3A with light / 8A with heavy cable.

A diagram illustrates a typical NMEA 2000 network setup. It shows a GPS Compass (SCX20) and a Multi-Function Display (MFD) (TZT12F) connected via drop cables to a backbone. The backbone has terminators at each end and is labeled with 'Backbone length'. Power is supplied to the backbone via a connection to a battery.

2. Basic Network Components

NMEA2000 networks require NMEA 2000 certified devices, approved tee-connectors, and cables. FURUNO USA supplies NMEA approved components.

2.1. Starter Kit

The NMEA2000 Starter Kit consists of:

• NMEA2000 Drop Cable, 2m (1 ea.)
• NMEA2000 Backbone Cable, 6m (1 ea.)
• NMEA2000 Power Tee, Micro F/F, 8m (1 ea.)
• NMEA2000 Tee-Connector, Micro F/F/M (2 ea.)
• NMEA2000 Micro Terminator, Micro Male (2 ea.)

Part Number: AIR-033-745

2.2. Connectors and Terminators

Images show various NMEA2000 connectors and terminators:

• NMEA2000 Tee Connector: Micro Female/Female/Male (P/N: AIR-052-531)
• NMEA2000 Micro Terminator: Micro Male (P/N: AIR-335-791)
• NMEA2000 Micro Terminator: Micro Female (P/N: AIR-335-792)

2.3. Cables

Images show different NMEA2000 cables:

• NMEA2000 Micro Cable: Micro Male/Female (1 meter: 001-533-060-00, 2 meters: 001-533-070-00, 6 meters: 001-533-080-00)
• NMEA2000 Micro Cable (Angled): Micro Male/Female, Angled (1 meter: 001-105-830-10, 5 meters: 001-105-840-10)
• NMEA2000 Powr Tee: Micro Female/Female (8 meters: AIR-335-792)

3. Network Designing

A diagram illustrates two segments, 'Segment "A"' and 'Segment "B"'. Segment "A" includes a GPS Compass (SCX20) and an MFD (TZT12F). Segment "B" includes an Autopilot Controller (NAVpilot300-FAP3001) and an Autopilot Processor (NAVpilot300-FAP3002). Both segments are connected via backbone cables and drop cables, with terminators at the ends of each backbone. Power is supplied to the network.

Three connection diagrams for power are shown:

• Diagram 1: Shows a single leg backbone power connection using a battery or an isolated power supply.
• Diagram 2: Shows a double leg backbone power connection using a battery or an isolated power supply.
• Diagram 3: Shows a multiple leg backbone power connection using isolated power supplies with a single-point common reference.

3.1. Network Power Source and Connection Type

The NMEA 2000 network must be electrically isolated from other circuits to prevent radio interference. A dedicated network power source is required, operating between 9-16V. The power source should be a single-point connection of a battery or one or more isolated power supplies distributed along the network. It should not be a combination of battery and power supply connections. Each power line must have its own fuse. Several power-connection types are available to suit your system.

Single Leg Backbone Power Connection: This is the simplest and most common method, suitable for most boats. It can be powered by a battery or an isolated power supply.

Double Leg Backbone Power Connection: This method increases total power capacity by separating segments. It requires a NMEA 2000 dedicated power Tee or power isolator. Both power legs must connect to an isolated power supply or a battery.

Multiple Leg Backbone Power Connection: For larger networks, multiple legs may be required. This method uses isolated power supplies only. Each power leg must be isolated from others, and a single-point common reference is necessary to avoid ground loops and maintain control of ground-voltage levels between nodes.

3.2. Estimated Voltage Drop and Effective Backbone Length

While the standard defines maximum backbone length, voltage drop is a critical factor in network planning. Voltage drop can be calculated using the formula: VD = 0.1 × NL × BL × Cable Resistance, where:

• VD = Voltage Drop (V)
• NL = total Network Length (m)
• BL = Backbone Length (m)
• Cable Resistance = 0.0057Ω/m for light cable

For 12V power networks, the voltage drop should be less than 1.5V. For 13.8V power (typical from an isolated power supply), it should be less than 3.0V.

A graph illustrates effective Backbone length versus Total LEN (Load Equivalent Number). The graph shows acceptable ranges for 13.8V and 12V power supplies. This method is not applicable to multiple power supply networks.

3.3. Drop Cable Length

The drop cable connects the backbone to a device. Each drop cable should not exceed 6 meters for stable communication. The total drop length per backbone should be under 78 meters.

A diagram shows a network with multiple devices connected via drop cables to a backbone.

3.4. Gender Distinction of Connector

Typically, female connectors are at the power supply side, and male connectors are at the power-consuming side to prevent accidental contact with live conductors. Furuno NMEA 2000 devices have male connectors. NMEA 2000 Tee connectors are designed so that devices connect to the center Female connector, while the Female and Male connectors at the sides are used for the backbone.

Diagrams illustrate the gender of connectors on tee connectors for device and backbone connections.

3.5. Termination Resistor

NMEA 2000 networks require two 120 Ω terminators, one at each end of the backbone, to prevent signal reflections. For a single power insertion network, one male and one female terminator are needed. For networks using a NMEA 2000 dedicated power tap cable, two male terminators are required. The total resistance of the finished network should be approximately 60 Ω.

Diagrams show network configurations with terminators.

3.6. Shielding

The NMEA 2000 network is isolated from other circuits, so the shield cable is not bonded to the device chassis. NMEA 2000 shielding must be continuous throughout the network and connected to RF ground at one single point.

Diagrams show the shielding connections for NMEA 2000 networks.

4. Field Programming (Instance Setup)

4.1. What is Instance?

NMEA 2000 devices offer customizable fields for onsite grouping and identification of data from duplicated or similar devices on the same network. Instancing is performed after installing NMEA 2000 devices.

• Device Instance: Assigned manually to NMEA 2000 devices to identify data from duplicated or similar devices. Proper instancing is crucial for a stable network. Each device outputting the same PGN (data) must have a unique instance (0 to 255).
• Data Instance: Identifies multiple PGNs carrying the same data from different sources transmitted by one device (e.g., an engine gateway or tank sensor connected to multiple level sensors). The valid range varies per PGN, and configuration depends on the gateway or sensor used.

A diagram shows a network with various devices, each assigned an instance number and type (e.g., Device 0 as GPS, Device 1 as GPS & heading, Device 0 as Tank Sensor).

4.2. Device Instance Setup via NavNet TZTouch2/Touch3

Steps for setting device instance:

1. Navigate: Home -> Settings -> Initial Setup -> Sensor List.
2. Open "Sensor List" under Initial Setup.
3. Select the product.
4. Tap on Device Instance for the sensor; a keypad will appear.
5. Enter the device instance, ensuring no conflict with other devices outputting the same PGNs.
6. Some devices require a power cycle to apply the change.

Screenshots show the process of selecting a sensor, viewing its details, and entering the Device Instance using a keypad.

4.3. Data Instance Setup via NavNet TZTouch2/Touch3

NavNet TZTouch2/Touch3 can configure data instance for applicable Furuno NMEA 2000 devices (e.g., IF-NMEAFI, software version 1.02 or later).

1. Connect an IF-NMEAFI to the MFD via NMEA 2000.
2. Navigate: Home -> Setting -> Initial Setup -> IF-NMEAFI Setup.
3. Select an IF-NMEAFI under the “Select IF" menu. Ensure only one IF unit is connected if multiple are present.
4. Tap the keyboard icon at “Fluid Instance"; a keypad appears.
5. Enter the fluid instance (0 – 14) to avoid conflicts with other Tank sensor devices.

Screenshots show the process of setting up Fluid Instance for a Tank sensor.

5. General Information and Required PGNS

Multi-Function Displays and Remote displays can use NMEA2000 sensors as direct or calculation sources for on-screen information. The following table explains general information and required PGNs. Note that the product must have the receiving capabilities for the PGN, and this varies per product. Refer to the operation manual for a detailed PGN list.

Navigation Data

Route Information

Wind and Weather

Engine and Tank

Combined NavData

Bold = Mandatory PGN, Nonbold = Either PGN will work