The multifunction screen, the window to your data

|10/08, 2021

The multifunction screen, the window to your data

Multi-function displays (MFDs) are a common device found in most NMEA 2000 networks. To start these devices are critical to maintaining a healthy NMEA network.

What is a Multi-Function Display (MFD)

What is a Multi-Function Display (MFD)

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Multifunction screens come in a variety of sizes and styles. Some are completely touch screens, while others are controlled with a combination of a display and soft keys for functions.


These are much more than just "screens". for your NMEA 2000 data. In fact, most modern MFDs can become the electronic "hub" or heart of your network. This is due to that modern MFDs can display AIS data, be a chartplotter, Fishfinder and some even support radar and video. The latest have alsoå Wi-Fi and Bluetooth communication that can link to your phone.


MFDs can display a LARGE amount of data, which is why they are so ; popular. Because NMEA 2000 data is binary, non-human-readable, you'd really struggle to get it right. your NMEA 2000 network and the data currently available on; the one without anything resembling an MFD.

Raymarine Axiom MFD 1

Raymarine Axiom MFD 1
It is worth emphasizing that not all MFDs have the same functionality. Some will have limited display options, while others like the newer Raymarine Axiom MFD  (pictured above) can display a variety of data.

A common feature of the latest MFDs is the internal GPS. Although the cost of the MFD may be a little higher for one that does not have internal GPS, the convenience of not needing an independent GPS saves both time and money overall. Internal GPSs are not as accurate as independent external ones, but for leisure cruising the internal GPS is more than adequate.

Så how does this relate to Actisense products?
One of our most popular products, Actisense EMU-1  (Engine Monitoring Unit) is an analog to digital NMEA 2000 unit for engine data. The unit takes analog inputs from transmitters/transmitters on; your boat's engine and converts this data to NMEA 2000 PGN. Once this data is output to the NMEA 2000 network by the EMU-1, it is available to all units. This is where MFDs come in, as they can display some or all engine data in a digital gauge and/or numeric format making it easy to read. Combine this with the alarm functionality of EMU-1 and MFD, så you can sail with confidence, knowing that if something goes wrong such as Engine Over Temperature, if you check for; to be warned by MFD. (Note that the EMU-1 has 4 configurable alarms).

Since all devices in a NMEA 2000 network communicate and share data thanks to CAN (Controller Area Network), this means that converted NMEA 0183 data alsoå can be displayed on MFD. The Actisense NGW-1 bidirectional conversion gateway can output NMEA 2000 PGN from the relevant converted NMEA 0183 sentences to the network, which the MFD then displays. This is an excellent way to save money when installing a NMEA 2000 network on; a replacement for existing NMEA 0183 instruments, as the NGW-1 is a fraction of the cost compared to a new NMEA 2000 GPS or AIS.

Ä Is MFD a thing of the past now that Wi-Fi Gateways and mobile apps exist?
The short answer is no. Although the DL's connection is widely used in the marine industry, this does not mean that NMEA 2000 MFDs should not be considered profitable. The main reason for this is security.

This connection should not be used as the primary method of data transfer, as it may suffer from disturbances and connection interruptions. If you are monitoring data that is not critical to the safety of the ship, at least there will be no big shakes if the connection is interrupted. However, if you are using a wired gateway and an app such as radar display and AIS overlay for targets and the connection is lost, you can potentially expose yourself and other boat people in danger. A physical "core connection" such as the NMEA 2000 backbone and drop cables should be used for safety-critical data, with the DL connection as a one-second or "repeat" display of the data .

A major limitation is the data format. Most mobile and tablet apps use NMEA 0183 as their data format, which has limited meanings compared to NMEA 2000 PGN. For example, if you want to monitor your engine data, this must be done with NMEA 2000, as there are no relevant conversions for Engine Data in NMEA 0183 other than RPM. This means that critical parameters such as oil pressure, boost pressure and transmission data are lost when trying to convert these to NMEA 0183. This reason alone means that MFDs are still are extremely useful for a boat. There are some NMEA 2000 apps made by manufacturers that work with their kit, but the vast majority of map apps in the 'app store' still use NMEA 0183,