MEWS: Marine Electronics Wiki

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== Electrical Power Supply Requirements ======

===== NMEA 2000 =====

I don't have the standard. The following is assembled from credible looking sources on the web.

Bus power supply standard from 9V - 16V. Presumably that is just a wide nominal 12V, rather than people actually choosing to use 9V.

**Load Equivalency Number** (**LEN**) - This seems to mean a **50mA** draw from the CAN bus power lines.

It will supply up to **3A total**.

Voltage drop must be <1.5V over whole network, to keep the data link happy.

Three different cable sizes are standard. The smallest one is common on boats.

"Lite" cable: 22 AWG power, 24 AWG data.
"Micro" connector.
57 mOhm per m.

==== Connectors ====

Physical layer of NMEA2000 is based on (same as?) DeviceNet.

Micro is M12. 5 pin, one in centre. Mini is bigger and has different pin layout with one at top.
"A coded".

  * Male on device.
  * Cables are male to female.
  * T-connectors (3 way junction) have M and F on the ends, F in middle to connect to device with M-F cable.
  * SeaTalkNG is same as NMEA 2000 but with a different connector.
==== Links ====

Has connector pinouts:
https://www.csselectronics.com/pages/nmea-2000-n2k-intro-tutorial


https://www.ibinews.com/ibi-presents/three-fundamentals-of-designing-a-fault-free-nmea-2000-network/44519.article

[[https://digitalyacht.net/nmea-2000-networking-guide/|Digital Yacht NMEA 2000 Networking Guide]]