Powered by your NMEA 2000 network

Running your NMEA 2000 network shouldn't be a chore or a difficult task, but there are various things to think about; during the planning stage, which will save a lot of time when it comes to installation. While this article can't cover everything, it will cover some of the basics.

So, how do you run your NMEA network? The first and undoubtedly the most important is a network diagram, which describes all cables, connectors and units that will be onå the network.

The diagram does not need to be to scale, or precise and a hand drawn diagram is sufficient, but the diagram is enough to do Do any voltage drop calculations when considering power implementation.

As a minimum, the diagram must include cable amounts, power input location(s), LEN (Load Equivalency Numbers) for each device and the only shielded wiring location connected to the ship's RF ground.

Firstörå load equivalence number (LEN)
The LEN is a way of representing how much current a device draws from the network, and every certified NMEA 2000 device has a LEN, which bö r is published by the manufacturer in the device documentation. You need this value to perform voltage drop calculations, as this is done using Ohm's Law.

1 LEN is 50mA, so 20 LEN är 1A. This is important, as any device over 20 LEN (1A) should not be operated from the NMEA 2000 network and requires its own independent power supply. Devices such as MFDs are usually powered from their own power supply, by due to their high power.

In principle, the higher the LEN, the higher the voltage drop, and usually higher LEN devices are placed closer to the current point of introduction; the network, to minimize the cable length, which in turn reduces the voltage drop.

Strength reduction points (s)
NMEA 2000- units require 9-16VDC (some are rated for 24V as is, to enable 24V power supply in large networks if all units are rated for r this).

Furthermore, each NMEA 2000 unit is powered to some extent from the bus; Each unit contains a NMEA 2000 transceiver, which takes its power from the bus. This means that even high current devices such as screens that are over 1A, they are basically powered from the bus, but the independent power supply requires vs for things like the screen etc.…

There are a number of different NMEA 2000 sizes, which include:

• Kä DC voltage (varies depending on manufacturer)
• Supplies battery connection 12.6 VDC
• Several power supplies 13.8 VDC (same manufacturer)
• AC to DC Supply 13.8 VDC
• DC to DC supply 13.8 VDC

Where the power was inserted into the network depends on the design of the installation. If a power-tee is used that can drive both the left and right sides of the trunk individually, then the NMEA 2000 power cable is preferably placed in the middle of the network.

However, if you have more high-power devices on one end, it would make more sense to place the power-tee closer to those devices . Some small Networks do not require a power tee, and can, for example, be powered from one end through a simple power cable (drop cable) and a 4-volt tee.

This highlights the purpose of the network diagram created before starting the installation as it allows you to determine where the power cut point should be.

På large networks with a high volume of devices, more than one power supply point may be needed to keep the voltage above 9V on the bus.

An ideal product for power reduction is the Actisense MPT-2 (Micro Power T-Piece), which can power the two sides and right side of the spine and comes with two female connectors to meet DeviceNet standards.

NMEA 2000 power wiring – The MPT-2 has 2 pairs of wires and a screen. One pair is red and black, the other is red/white and black/white to distinguish between the power connections on the left and right side.

Your network should always be grounded on; a place. Having multiple grounding locations can cause ground loops that can interfere with the device's communication on the network. Make sure that the correct fuses are used on; the power connection, which is sufficiently rated for your power supply.

A quick and easy way to determine if your network is correct Our recommendation is to use our smart terminators (A2K-TER-U). These intelligent terminators have built-in LEDs that change color to indicate the voltage level on the the frame with the help of the built-in voltage monitoring circuit with high accuracy. If it detects that the voltage is within the minimum required range, it will indicate "GREEN" immediately, providing continuous valuable feedback on the condition of the bus.

About Voltage the profit falls below the minimum levelå which is required for 9.0V, the LEDs will illuminate "RÖD", indicating a potential problem with the NMEA 2000 bus current. På likewise, if the LEDs are not lit at all, this would indicate that there was no power or that the polarity was incorrect. This monitoring function is continuous and remains permanent.

Using these terminators means that a short visual check can be made as the highest diagnostic level for any strö mproblem på a network, as the LED indicates if there is low voltage or incorrect polarity, saving time and effort for your installer. disconnect the terminators and use a multimeter.