Installation manual

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Installation and wiring | AC12N/AC42N Autopilot Computers
Polarity protection
¼ Note: The fuse located in the lower left corner of the AC board is not
put in its final position when supplied from factory.
When the motor supply is connected to the terminal, a diode will
light. If the light is red, you have to swap the wires. When the light is
green, the polarity is correct. Switch off the supply voltage and put
the fuse into the correct position.
Radio Frequency Interference (RFI)
The autopilot system has excellent RFI protection as per EMC
Directive 2004/108/EC.
NMEA 2000 (or compatible) cables and other signal cables
(feedback, or others as required) should not be run in parallel with
other cables carrying RF or high current, such as VHF and SSB
transmitters, battery chargers/generators, winches and thrusters.
¼ Note: If problems occur with RFI, make provisions to connect the
supply cable shield to the fast-on ground terminal. This terminal
must also be connected to the hull bonding.
Introduction to NMEA 2000 (SimNet)
NMEA 2000 is a combined electrical and data specification,
and is based on CAN (Controller Area Network - SAE J1939) bus
technology. NMEA 2000 permits exchange of data and commands
between the interfaced products. NMEA 2000 stipulates the use of
Micro-C and Mini-C hardware for the physical aspect of the network.
Most NMEA 2000 devices can be connected directly to the NMEA
2000 backbone and SimNet devices can be connected by using
adapter cables.
Essential network information
• NMEA 2000 is a powered network. It must have a separate 12-15 V
DC power supply protected by a 5 Amp fuse. Do not connect the
NMEA 2000 power cable to the same terminals as the start batteries,
Autopilot Computer, Radar, thruster or other high current products
• An NMEA 2000 network consists of a linear “backbone” from which
“drop cables” connect to the NMEA 2000 devices
• A single drop cable has a maximum length of 6 m (20 ft). The total
length of all drop cables combined should not exceed 78 m (256 ft)
• An NMEA 2000 network has a maximum cable length of 100 m (328
ft) between any two points