Furuno CAN bus Network Design Guide
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RD-33
NMEA0183
NMEA0183
NMEA0183
MFD
NMEA0183
(MAX. 3 units)
NMEA-CAN bus
Interface unit
IF-NMEA2K1
Device
Power supply
A diode and a polyswitch (SMDC110F) on CONT2 board in the MFD unit protect the interface
circuit against over-current and short-circuit. See Fig.33.
J3 DATA2
J702
J501 J4 NMEA2000
NET_S_IN >17>
>1>
>1>
>2> NET_S
NET_C_IN >18>
>2>
>2> >3>
NET_C
>3> >3>
>4>
NET_H
>5> NET_L
Fig.33 Protection of network power circuit in MFD
The maximum length of the network backbone is 150 m when the heavy cable is used and 50
m when the light cable is used. More details are explained in the “CAN bus Network
limitations” section.
1.8 Network Grounding
The network is grounded at a SINGLE location. This is normally done at the power supply
connection to the network and should be well connected to the vessel’s grounding system.
There must be no other ground connections on the network to avoid the problem of ground
loops, which can harm the network performance.
1.9 Connecting NMEA 0183 Device
An NMEA 0183 device is connected to the CAN bus network via MFD unit or by using
NMEA2000 Interface unit, IF-NMEA2K1.
Fig.34 (a) Connection of NMEA0183 to CAN bus network
with MFD and IF-NMEA2K1
The remote display RD-33 is also capable of converting the NMEA0183 signal to the CAN
bus signal.
Fig.34 (b) Connection of NMEA0183 to CAN bus network with RD-33
CONT1
CONT2
1.1A
NMEA0183
Terminator
Terminator
