Collecting NMEA Data With Fewer Wires
When we originally developed Rockit we used various rough and ready methods to get data into the Laptop we were using to run the software. Back then, circa 2016, cue a certain amount of nostalgia, we used to connect things together by twisting wires; all the things you aren’t supposed to do to make safe electrical connections..
You could say our wiring looked slightly agricultural it but owed more to the techniques I was using to build a model train set with my son… in fact quite of a lot of the tools we used were borrowed from the train set project.
Time has moved on, the 10 year old is at university and we can now buy a range of products off the shelf that make it really easy to extract data from a boats network all with a bare minimum of wiring.
What do you need to get started ?
We have been using W2K-1 units from Actisense for the last three or four seasons.
They are very easy to setup.
To get started you need access to your boats NMEA 2000 network. The W2K-1 connects direct to the NMEA 2000 bus so there is no need for an NMEA 2000 to 0183 converter.
To complete the installation you will also need a laptop or tablet to do the initial configuration of the device.
You will need an NMEA 2000 T Piece to insert into your boats network.
Pick the cabling standard that matches your boats equipment. There are differences in the cable ends/connectors that Raymarine, Garmin, B&G, etc use so make sure your T Piece will connect. NMEA 2000 cabling is relatively complicated in terms of what does and doesn’t work but if you follow a guide like the one on the Actisense website on the link below you won’t go far wrong.
https://actisense.com/complete-guide-to-building-an-nmea-2000-network/
The key is that the T piece connects into the backbone cable that all the other units hang off. The W2K-1 is the on a relatively short drop cable connected to the third connection on the T Piece.
Our J109 test boat has a handy panel next to the chart table that acts as the brains of the boat. The VHF, Chartplotter and a load of other “must have” electronics live there including our test Rockit Server Device.
We plugged our T Piece in there with a NMEA cable long enough to have the W2K-1 located next to a couple of other boxes that we need to be able to access without using a screw driver. They are in a space under the chart table by the Navigators knees.
As you can see from the image its not an elegant solution but it does work, we can check the LED’s on the W2K-1 and get to the SD card that is inside the case to download data if we need to.
Do I Want To Collect NMEA 2000 or 0183 Data ?
Once you have connected the device to your network it gives you some really useful functionality.
The W2K-1 has a wide range of data formats that it can read and transmit data in. The full list is in the W2K-1 manual on the Actisense website here;
https://actisense.com/wp-content/uploads/2020/01/W2K-1-User-Manual-issue-2.10.pdf
In the context of the Rockit software we are using two formats and only reading the data. We don’t transmit anything back to the NMEA bus.
NMEA 0183; an easy to process form. For those of you who have an older Actisense NGW-USB device this is basically the same as the data format you get on the serial port.
The W2K-1 is converting NMEA 2000 to NMEA 0183 using the same conversion mappings. Most of the NMEA 2000 data points are accessible thought that conversion process. The only exceptions being where there is no NMEA 0183 equivalent to the NMEA 2000 data; rig load data and pitch/yaw/trim would be examples where there are no equivalents. But most of the useful navigation data is there.
N2K Ascii; another easy to process format as its text in the same way as the NMEA 0183 feed. If you understand the NMEA 2000 standard the messages are reasonably easy to extract. You can buy the standard definitions from the NMEA. Follow the link below for the NMEA website. The NMEA are the industry body that controls the various marine data exchange formats, protocols and standards.
This data feed includes all of the NMEA 2000 PGN’s, the W2K-1 is pulling the data together from the packets that run on the NMEA 2000 bus and assembling the data into a form that can be easily read and collected.
Which feed to take ?
Rockit will process both NMEA 2000 and 0183 data in more or less the same way standardising the information received before aggregating it to produce the information that is displayed. Generally the default would be to collect NMEA 2000 data if its available. If you only have NMEA 0183 information from what is effectively a legacy system then go with the 0183 feed.
Using The W2K-1 As A Wi-Fi Hotspot
The W2K-1 has a few other useful attributes.
Once you have connected the device to your NMEA network and powered it up you will have a new Wi-Fi hotspot to connect to.
You need to connect your laptop or Tablet to the Wi-Fi hotspot to do the configuration. The login details for the Admin User and Wi-Fi hotspot are on a sticky label on the W2K-1 device. Its worth making a note somewhere useful of what those are otherwise you will need to dig the W2K-1 out every time you want to add a new computer to the Wi-Fi hotspot.
Once connected you can open the Admin console for the W2K-1 using a web browser. The Admin Console runs on an http rather than https protocol session in the browser so you may need to over ride the security warnings in a browser like Chrome.
First change the Admin password. I have visions of my competitors hooking into the instruments on my boat via the W2K-1 hotspot as I’m sailing along and stealing the data, but, I think they would be sadly disappointed. Changing the password is done through the Admin Console and described in the manual (see the link above).
Some of the admin tasks make the W2K-1 reboot to take effect. Generally the device will restart and reconnect to the browser session. If it doesn’t just use the browsers refresh button to reconnect. Write the Admin password down somewhere secure … if you loose that you are looking at a factory reset of the W2K-1.
Because the W2K-1 acts as a Wi-Fi base station its possible to create a small Wireless network onboard. We connect a Rockit Server Device and a Laptop onboard using the W2K-1 as the network hub. The W2K-1 makes it possible for us to access the Rockit data on the Rockit Server from a laptop. We run the Rockit Analytics Desktop on the Laptop connecting to the Rockit database on the Rockit server via the W2-K device.
It sounds complicated but its relatively simple to setup and doesn’t require much in the way of cables. One for the W2K-1’s connection to the NMEA 2000 bus and one for the 12v DC supply to the Rockit Server
Setting The Data Transmit And Receive Protocols
The W2K will transmit and receive on three different ports.
You need to decide which data formats you want to transmit and receive.
For a Rockit installation we will setup two of the three server ports to be N2K ASCII and NMEA0183.
What you do with the final port will depend on any other applications you want to use with the W2K-1. Actisense RAW is the most efficient format to use and will often be used by third party software developers to develop Apps that send and receive NMEA 2000 data.
You are definitely going to want to write down the port numbers and the data being format being transmitted.
Once you have the Port numbers you can setup the connection to the NMEA data source in Rockit. This is described in detail in the Rockit user guide here;
https://ashtree-marine.com/user-guide/2022/11/23/collecting-information-from-your-boats-network
Connecting The W2K-1 To Another Wi-Fi Network And Other Devices
Its also possible to connect the W2K-1 to another Wi-Fi network..
So if you have another network that links together the computing devices on your boat you can make the W2-K accessible on that network; and effectively create an NMEA data source for them to connect to.
We make extensive use of this feature in our test lab where the W2K-1 is integrated into office network. We send simulation data to a test NMEA 2000 bus using an Actisense NGW and a piece of software called NEMA Studio. The developers can then access the NMEA 2000/0183 data using the W2K-1’s Wi-Fi client function.
Its useful if you have a Cellular modem connected so that devices connected to the boats Wi-Fi network can access the internet. Connecting to the W2K-1 via the other network gives you access to both the NMEA data and the internet. Connecting to the W2K-1 itself wouldn’t give access to the internet just the devices connected to W2K-1 itself.
So Whats The Finished Result ?
The W2K-1 gives us the ability to collect and transmit NMEA data. It also gives us the ability to run a small Wi-Fi network onboard. Its a rugged simple to install device.
We use our device extensively both onboard and in our test environments.
Its become our preferred method of collecting NMEA data due to the simplicity of installation and the continued support and update of the product by Actisense.
Actisense also answer the phone and seem genuinely interested in helping you get their products working.
All of which makes getting the most out of the device relatively straightforward which in turn makes it easy to setup the Rockit software to collect NMEA data for analysis.
Bill/January 2023