Lambda Marine - The Ultimate Actisense NMEA 2000 Network Solutions Guide
All you need to know to build your Actisense NMEA 2000 Network

NMEA 2000 Networks – The Basics

NMEA 2000 is an open standard designed by the NMEA organization to standardize the messages and connector system used for connecting NMEA 2000 compatible devices in the marine industry. NMEA 2000 devices can be anything from a simple GPS system, or a complex Radar system, to an advanced Engine Monitoring system. NMEA 2000 devices will only communicate with each other when connected to a powered and correctly terminated NMEA 2000 network. It is not enough to simply connect two NMEA 2000 devices directly together. All networks need to be powered and terminated correctly to allow data to be transmitted reliably on the network.


As shown in figure 1 above, NMEA 2000 networks consist of:

  • Backbone: The main trunk of cable that runs through the boat to form the network, either with one end-fed power point (1 segment) or one mid-fed power insertion point (2 segments)
  • T-pieces: are connected along the network for NMEA devices to plug in to using a drop cable
  • Instrument drop: The length of drop cable that connects an NMEA 2000 device to the backbone

An example of a full NMEA 2000 network is shown below.

Image adapted from Maretron

All NMEA 2000 networks require a 12V DC (or 13.8VDC) supply. In addition, a correctly functioning network will require at the minimum the following components:

  • 1 x Power-T (to insert network power, should be fused)
  • 2 x Terminating Resistors (to terminate the network on both ends of the backbone)
  • 2 x T-Pieces (one per connected device)
  • 2 x NMEA 2000 Devices (such as the Actisense EMU-1 and/or any other NMEA 2000 certified device from various manufacturers such as Radars, Chartplotters, GPS etc.)

T-Pieces are needed to connect each device to the network. Additional cable lengths can be used between any of the connectors to extend the length of the network, whilst ensuring that the NMEA 2000 rules for cable lengths are adhered to, see below “Table 1 - NMEA 2000 Cable Length Rules”. All the required NMEA 2000 network parts can be supplied by Actisense via Lambda Marine.


Max Length
Max Amp Power Pair Data Pair
Dropcable
6m



Sum of all dropcables
78m



Backbone maximum cable length (terminator-to-terminator)
100m
3A/seg AWG 22
AWG 24


In addition, NMEA 2000 networks should be designed adhering to below rules.


Rule Notes
Maximum Number of NMEA 2000 Devices per Network 50 Depending on backbone length and LEN
Equivalent Network Load for all devices (LEN) per Backbone Segment 60 Depending on backbone length
Maximum Voltage Drop per Backbone Segment 3V@13.8VDC
1.5V@12VDC
13.8VDC recommended for higher backbone lengths and/or high LEN
Maximum Current per NMEA Device 1A =20LEN
Power Insertion Point Mid-Feed
End-Feed
Mid-Feed=2 backbone segments totally 100m
End-Feed=1 segment max 50m

NMEA 2000 vs NMEA 0183 Comparison

Older Marine Electronic Devices commonly have NMEA 0183 interfaces. This is an older standard, but is still widely used, especially on commercial IMO SOLAS vessels.



NMEA 0183 Typical Network
NMEA 2000 Typical Network

As is immediately obvious from above diagrams, NMEA 0183 uses significantly more cabling to connect all devices. On larger vessels using NMEA 2000 cabling can save as much as 150kg weight and 3 weeks cable running labor, due to the central backbone topology.

Other differences include:

NMEA 0183
NMEA 2000
One-way communication, non-prioritized
Bi-directional, prioritized
Connects only Navigation and Communication Devices
Connects NavCom, as well as engine data and Tank Level Sensor Devices
Relatively slow (4.8kbps)
Very fast (250kbps / 50 x times faster than NMEA 0183)
More complex to set-up, one-to-one cabling necessary, different types of connectors depending on Device Manufacturer Plug & Play technology, one bus Cable, standardized connectors
Higher Total Cost Of Ownership due to longer more expensive cable runs, cable running labor, network configuration labour
Lower Total Cost Of Ownership due to less cabling to be purchased and installed

Actisense NMEA 2000 Network Solutions

Actisense offers a complete NMEA 2000 Network Solution, consisting of:

  • NMEA 2000 Backbone Components – To create a NMEA 2000 network backbone
  • NMEA 2000 Drop Components – To create NMEA 2000 device drops
  • NMEA 2000 Gateways – To put analogue engine data on the NMEA 2000 network or to connect a PC
  • NMEA 2000 Convertors – To convert NMEA 2000 to NMEA 0183 and vice versa or to USB or RS232/422

To design your NMEA 2000 Network, Actisense offers 4 types of solutions based upon 4 different types of backbone Power-Insertion Components. All, except the A2K-SBN, can be customized and expanded. Sample diagrams are included hereafter.



A2K-SBN
A2K-RSK
A2K-KIT
QNB-1





Number of NMEA Devices 4, not expandable
Standard 3, expandable to 25*
Standard 2, expandable to 50*
Standard 6, expandable to 50*
Backbone Length N/A
0-50m, recommended 10-15m*
0-100m, recommended 15-50m*
0-100m, recommended 25-50m*
Network Topology End-fed, self-contained backbone with terminators and 4-way T-Piece.
End-fed or mid-fed but with only 1 x 3VDC power for both backbone segments.
Mid-fed, with 2 x 3VDC, one for each backbone segment.
Mid-fed, with 2 x 3VDC, one for each backbone segment.
Power Cable Length
3m
3m
3m
3m, expandable
Other
Ideal for very small boats with maximum 4 NMEA 2000 Devices, not customizable
Ideal for small boats, with initially 3 NMEA 2000 Devices, expandable to max 10-25 NMEA Devices* Limited customization
Ideal for small, medium and large vessels, fully customizable
Ideal for large and very large vessels, fully customizable, can be connected to mid-size backbone cable



Actisense NMEA 2000 Network Examples

Actisense A2K-SBN NMEA 2000 Network Example
Actisense A2K-RSK-1 NMEA 2000 Network Example
A2K-SBN-1 Solution – 4 Devices
A2K-RSK-1 Solution – Low Device Density – 6 Devices

Actisense A2K-KIT NMEA 2000 Network Example
Actisense A2K-QNB-1 NMEA 2000 Network Example
A2K-KIT Solution – High Device Density – 15 Devices
QNB-1 Solution – Very High Device Density – 27 Devices

Actisense NMEA 2000 Backbone Components

A2K-SBN-1 A2K-RSK-1 A2K-KIT-1 A2K-KIT-2 QNB-1
A2K-SBN-1
A2K-RSK-1
A2K-KIT-1
A2K-KIT-2
QNB-1/QNB-1-PMW
NMEA 2000 Small Boat Network
NMEA 2000 Reduced Starter Kit
NMEA 2000 Network Kit (with A2K-TDC-2m cable)
NMEA 2000 Network Kit (with A2K-TDC-6m cable) NMEA 2000 Quick Network Block
Suitable for: Very small vessels
Suitable for: Small Vessels
Suitable for: Vessels of any size; small, medium, large, very large
Suitable for: Vessels of any size; small, medium, large, very large
Suitable for: Vessels of any size; small, medium, large, very large, ultra-large

A2K-MPT-1 A2K-T-MFF A2K-4WT A2K-TER-F A2K-TDC-10m
A2K-MPT-1
A2K-T-MFF
A2K-4WT
A2K-TER-F/M
A2K-TDC-XM
NMEA 2000 Power Tap
Micro T piece for insertion in the backbone to connect one NMEA 2000 Device.
Micro 4-way T piece for insertion in the backbone to connect up to 4 NMEA 2000 Devices.
Micro terminator female/male, to terminate the backbone cable on one end.
Micro backbone cable assembly, UL certified cable, available in 0.25/0.5/1/2/3/4/5/6/8/10m length (also in 100m bulk-reel)
Suitable for: A2K-KIT and A2K-RSK Networks, small to very large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels

Actisense NMEA 2000 Drop Components

A2K-4WD-1 A2K-TDC-6M A2K-FFC-SF A2K-FFC-RF A2K-PMW-F
A2K-4WD-1
A2K-TDC-XM
A2K-FFC-SF/SM
A2K-FFC-RF/RM
A2K-PMW-F/M
Micro 4-Way Drop, includes a backbone connector, 2m drop cable and a 4-way drop T-Piece. Total drop cable length, including 4 device connection cables, should not exceed 6m.
Micro drop cable assembly, UL certified cable, available in 0.25/0.5/1/2/3/4/5/6m length
Micro field fit connector, straight – female/male
Micro field fit connector, right-angle female/male
Rear panel mount wired, 5 pin micro female/male
Suitable for: A2K-KIT, QNB-1 and A2K-RSK Networks, small to very large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels

A2K-GCF-0M25 A2K-COVER-20-F


A2K-GCF-0M25/ GCM-0M25
A2K-SCREWCAP-10-F/M
A2K-COVER-20-F/M


Micro gender changer (female to female or male-to-male) 0.25 metre, UL certified cable
Protective SCREW cover for NMEA 2000 female/male Micro connectors (Bag of 10 pieces)
Protective cover for NMEA 2000 female/male Micro connectors (Bag of 20 pieces)


Suitable for: A2K-KIT, QNB-1 and A2K-RSK Networks, small to very large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels



Actisense NMEA 2000 Gateways & Convertors

EMU-1-BAS NGT-1-USB NGW-1-ISO NGW-1-ISO-AIS NGW-1-STNG
EMU-1-BAS
NGT-1-USB/ISO
NGW-1-ISO/USB
NGW-1-ISO-AIS
NGW-1-STNG
Engine Monitoring Unit, Analogue to NMEA 2000 signal convertor, standard configuration
NMEA 2000 PC Interface, standard version with USB or specialized version with RS422/323 serial. Required to program/configure/ monitor EMU-1 via PC or to connect the NMEA 2000 network to a PC to monitor any NMEA 2000 data.
NMEA 0183 to NMEA 2000 Gateway, standard configuration with ISO bare wiring or USB connector, converts NMEA 0183 to NMEA 2000 or vice versa
NMEA 0183 to NMEA 2000 Gateway, pre-configured with AIS conversions, with ISO bare wiring, converts NMEA 0183 to NMEA 2000 or vice versa
NMEA 0183 to SeaTalk NG Gateway, with SeaTalk NG to NMEA 2000 adaptor cable (drop), converts NMEA 0183 to Raymarine SeaTalk NG and vice versa
Suitable for: A2K-KIT, QNB-1 and A2K-RSK Networks, small to very large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels

DIN-KIT-1 DB9-F


DIN-KIT-1
DB9-F



Kit of 2 clips & 4 screws. Use with EMU-1-BAS on top hat (EN 50 022) or G section (EN 50 035) rails
9 pin, D type moulded cable assembly (female), can be used with NGT-1-ISO and NGW-1-ISO convertors.



Suitable for: A2K-KIT, QNB-1 and A2K-RSK Networks, small to very large vessels
Suitable for: A2K-KIT, QNB-1 and A2K-RSK-1 Networks, small to ultra large vessels




Actisense Unique Selling Points

Actisense products are unique in their quality, reliability, durability, smart intelligence and sophistication. Unique features include:
  • Unique Actisense Smart Intelligent technology for superior NMEA network performance
  • Design approach focuses on quality
  • Reliable, durable and strong
  • Best solutions with today’s technology whilst constantly researching tomorrow's technology
  • Flexible, galvanically opto-isolated inputs, protecting devices from high-voltage spikes, noise, electrical interference and ground loops
  • Unique Actisense ISO-Drive technology outputs to intelligently isolate devices and provide safe connections to RS232 and RS422 ports
  • Designed for use with all NMEA 0183 input & output types (RS422, RS485 & RS232), all products surpass the NMEA 0183 specifications
  • Cost effective yet high quality for superior value for your money
  • NMEA 2000 certification for trouble-free network operation, exceeding products merely "NMEA 2000 compatible"
  • Quality manufacture with 3 year guarantee

To request a full PDF copy of this guide with additional info, feel free to contact sales at Lambda Marine by email.