Installation Instructions

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NMEA2000 / SimNet | NSS Installation Manual
NMEA2000 / SimNet
NMEA 2000 is a combined electrical and data speci cation.
NMEA2000 and SimNet is a data network based on CAN (Control Area Network) bus technol-
ogy that makes interconnection and integration of Simrad and other NMEA2000 products
simple. NMEA2000 permits exchange of data and commands between the interfaced
products. The data transfer capacity of SimNet is 50 times higher than that of the NMEA0183
standard at 4800 baud.
Certain NMEA0183 data can be converted to and from the SimNet network by;
• using the NSS display to bridge data (internally).
• using an optional external converter unit such as the Simrad AT10.
• using a third-party NMEA2000 to NMEA0183 bridge.
Most NMEA2000 devices can be connected directly to a SimNet backbone and SimNet
devices can be connected to a NMEA2000 network by using adapter cables. (see ‘Simnet
Cables’ on page 60)
Note: The NSS has a Micro-C NMEA2000 connector and is fully compatible to work in a
SimNet network.
SimNet: The basics
• SimNet is Simrad’s proprietary network based on NMEA2000 CAN bus (SAE J1939 protocol).
• SimNet 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 SimNet power cable to the same terminals as the start bat-
teries, Autopilot Computer, Radar, thruster or other high current products.
• A SimNet network consists of a linear “backbone” from which “drop cables” to SimNet devices
connect. Devices that have more than one SimNet connector can be part of a SimNet
backbone (daisy chained) (But not as part of a NMEA2000 backbone).
• A drop cable is a SimNet cable that connects a SimNet device to the backbone. A drop cable
has a maximum length of 6 m (20 ft).
• A SimNet Network has a maximum cable length of 120 m (394 ft), which includes drop cables
+ 30 m (98.5 ft) mast cable. Total 150 m (500 ft) max.
• A SimNet 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 (red cap)
• a terminator plug (red cap)
• terminated in-line joiner (red locking collars)
• a wind transducer (terminator is in the mast head unit as opposed to mast cable).
• Certain Simrad products have two SimNet connectors, which can be made to be part of
the backbone. Connecting from device to device is known as ‘daisy chaining’ This network
topology is not o cially NMEA 2000 compliant.
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• NMEA2000 devices can be connected to the SimNet Network providing they:
• are NMEA2000 certi ed
• meet the CE, FCC regulations with a SimNet adapter cable
• do not exceed the SimNet load speci cation (please refer to separate document
Simrad SimNet Installation Manual (20222006)
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