Installation manual

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Installation and wiring | AC12N/AC42N Autopilot Computers
• An NMEA 2000 network needs to have a terminator at each end of
the backbone. A terminator can be one of the following:
• a power cable with built in terminator
• a terminated blanking plug
• a wind transducer (terminator is in the mast head unit
as opposed to the mast cable).
• Certain products have two Micro-C or SimNet connectors, which
can be made to be an in-line component of the backbone.
Connecting from device to device is known as ‘daisy chaining’. This
network topology is not officially NMEA 2000 compliant.
Planning and installing a network backbone
Plan the backbone carefully.
The NMEA 2000 backbone needs to run between the locations of all
products you want to install, typically in a bow to stern layout, and
should be no further than 6 m from a device to be connected.
Choose from the following components to make up your NMEA
2000 backbone:
• Micro-C cables: Available lengths from 0.4 m (1.3 ft) to 25 m (82.5 ft)
• Micro-C power cables with or without termination
• T-connector: Use at locations where you want to connect a device
by drop cable
• Wind transducer: If using a wind sensor, plan to connect this to one
end of the backbone, as this has a built-in terminator
• Micro-C male and Micro-C female to SimNet adaptor cables for
connecting to existing SimNet bus, or adding devices fitted with a
SimNet connector to a Micro-C network.
Power the network
An NMEA 2000 network requires its own 12 V DC power supply,
protected by a 5 amp fuse or breaker.
In smaller NMEA 2000 systems, the power connection may be made
anywhere in the system.
For larger systems, introduce power at a central point in the
backbone to “balance” the voltage drop of the network. Use a power
cable without termination.
¼ Note: When joining an NMEA 2000 network to a SimNet network, it
is not necessary to introduce power to both.