networks

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One of the major advantages of modern marine equipment is the ability to integrate data.  One screen could combine charts, radar images, and AIS information. However, to accomplish this the devices must be compatible through a network.  There are different types of networks and Fir will use several.

NMEA 0183

NMEA 0183 is an older marine CAN Bus (Controller Area Network) setup designed to allow electronic control units and devices to communicate with each other in applications without a host computer.  For instance,  a GPS antenna transmits a message on a wire where multiple devices can be connected and receive the information. NMEA 0183 is a simple, yet extremely reliable setup.  We will use this design for our Autopilot because it is a critical system.   

NMEA 2000

NMEA 2000, or N2K, is the latest marine CAN Bus system.  Unlike 0183, N2K is a plug-and-play communications standard used for connecting marine sensors and display units within ships and boats.  A GPS antenna, sounding transducer, and weather station transmitting on the same wire can be read by several devices.  The limit on the number of devices can be manipulated relating to the power consumption of the each, and the length of wire. 

When CAN Bus systems transmit data, they sent out a code (PGN) that tells all receiving devices what information is to follow. The receiving devices respond to this message is based on the PGN being requested, and whether the receiver supports the requested PGN pertaining to the job.  N2K has considerably more marine specific codes than NMEA 0183 therefore, we are exploring the possibility of the N2K transmitting data to the Wheelhouse.

 Typical NMEA system.

Typical NMEA system.

We like the N2K because it allows you to integrate equipment from different manufacturers.  This system enables a Garmin chartplotter to communicate with a Furuno gyro compass because a standard PGN is used. Most marine devices are N2K compatible.  

Since we are obtaining the latest technology and equipment athe N2K is a significant part of our automation plan.  This network will integrate devices to perform functions throughout the ship.  As a precaution we intend to isolate a backup system for the unexpected.   

Ethernet

Ethernet is a digital communications network used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). Ethernet was introduced in 1980 and updated ever since. While reliable in connecting computers to the internet, it is also susceptible to computer viruses. We will take preventative measures to safeguard against compromise. In addition, we intend to keep our marine systems isolated from the internet.

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