Sunday, 21 July 2019

Summer Maintenance in London #3

Hi everyone,
Last week we received a new toy - an Airmar 220WX weather station.  We installed it this weekend.

The 220WX is an impressive instrument  It connects to a NMEA2000 network directly.  It provides the following information:

  • GPS (lat, lon, cog, sog, time etc)
  • Compass heading
  • Wind speed and direction (apparent and true)
  • Wind chill (apparent and true)
  • Attitude (yaw, roll and pitch)
  • Attitude rate (rate of turn, roll and pitch)
  • Air temperature
  • Atmospheric pressure

Wind is measured ultrasonically in the slot in the instrument.  We've gone without wind data to date and estimated it in our log and blogs.  Wind data may allow our autopilot to "steer to wind" - if we can get it's NMEA2000 input working.  The 3D attitude and rate information may assist a future autopilot in difficult conditions.  Atmospheric pressure and air temperature will assist weather forecasting.

Unpacking
We mounted the unit on the goal post.  In future we may elevate it on a post for clearer air flow.

Airmar 220WX Mounted
On the Pushpit
As usual with goal posts the mounting was easy but running the cable less so.  We had left two unused coax cables running through the s/s tubes - one for an old GPS antenna and the other for our old Iridium GO antenna.  Sadly they both had to go.  Happily the 220WX NMEA2000 cable got through the s/s tube to the lazarette.  Its connector had to lose its collar which was too wide to fit.

Zen Again's NMEA2000 network now includes the following:

  • Vesper XB8000 AIS transceiver with WiFi hotspot
  • Garmin VHF300iAIS DSC VHF with AIS receiver
  • Garmin GPSmap451 chartplotter
  • Raymarine SPX5 autopilot (connected but not yet configured)
  • Airmar DST800 log, depth, water temperature
  • Airmar 220WX weather station

With the 220WX on the network we could see it on the chartplotter.

On the NMEA2000 Network
To test accessibility of the 220WX's data within the NMEA2000 network we setup various data on the GPSmap's data page.  This highlighted the main issue we face with the 220WX - most NMEA2000 displays can't show all data.  In particular attitude and attitude rate are not widely supported.  We can display wind, air temperature, atmospheric pressure and GPS data.

GPSmap ChartPlotter Data Display
The final step was to test accessibility of data beyond the NMEA2000 network via WiFi.  This includes what data the WiFi hotspot server transmits and what data the client app can display.  On our WiFi network we have MacBooks, iPads and iPhones.  The iOS devices run the iNavX general navigation app and Airmar's OnSiteWX instrument display app.

Our XB8000 NMEA2000 AIS includes a WiFi hotspot.  Like many such devices it actually translates NMEA2000 data to NMEA0183 prior to transmission.  Many newer parameters (such as attitude and attitude rate) were not standardised in NMEA0183 since they weren't widely available at the time.  This filters data availability.

We really like the iNavX chartplotter app.  It displays Navionics charts and overlays AIS data neatly. However its instrument page is text-only and has a limited parameter list.  At least it can display wind...

iNavX instrument display
OnSiteWX gets closer to our goal with customisable pages and a wide array of parameters.  However it isn't receiving all the 220WX's data...

OnSiteWX customised Location and Weather display
OnSiteWX customised Wind display
OnSiteWX customised Speeds & Courses display
No attitude data...
OnSiteWX attitude display (no data!)
Another nice feature of OnSiteWX is its ability to display trends.  We're yet to try this.

We've been researching WiFi hotspots to find units which transmit all the data on our network.  Most don't but we think we've found one.  If so that will be the topic of our next blog.

220WX
In the mean time we're very pleased with the 220WX.  The number of sensors in such a small package is impressive.  The price is a little scary until one adds up the cost of getting all the data from a set of instruments.  Works for us!

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