AutoTrackRaymarine Evo
Developer: Douwe Fokkema
Purpose
Provides automatic following of routes defined in OpenCPN through a Raymarine Evo autopilot and will also function as a remote control for that autopilot.
Installation
Installation is done through the Plugin Manager of OpenCPN. In OpenCPN, go to Options→Plugins and click Update Plugin Catalog: Master. Locate AutoTrackRaymarine and select it. Click Install.
To use the plugin you need an NMEA2000 connection to the Raymarine network. To connect to a NMEA2000 network, use any of the interfaces supported by OpenCPN. The current version will run on all platforms supported by OpenCPN. AutoTrackRaymarine works fine with OpenCPN version 5.8.4 and later. OpenCPN version 5.12.2 or later is preferred, in that version some issues in the Route Manager have been solved.
Operation from the Raymarine Control Head (P70)
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Make your route in OpenCPN.
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Activate the route in OpenCPN. Check that the active waypoint is the one you want to pass first.
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Put the ship on course.
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Press Auto on the Raymarine P70 pilot head.
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Pilot takes over as usual.
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Press auto again.
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Plugin takes control of the autopilot and will steer your ship along the activated route to your destination, and follows the route with a margin (XTE) normally less than 2 meters, independent of cross currents and compass errors.
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Caution: Only thing to do is keep a lookout for obstacles and traffic.
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As soon as you press Standby the autopilot returns to standby and you can steer manually again.
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When you press one of the buttons +/- 1 or 10, pilot will switch to regular auto on the last heading plus the button you pressed.
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Auto button when pilot is in auto activates the tracking again.
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When you press auto again when the plugin is tracking a route, XTE will be made zero. You will then head from the current position straight for the active waypoint.
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A good quality GPS position is essential for the operation of this plugin.
Operation from OpenCPN Plugin Interface
Alternatively AutoTrackRaymarine may be controlled from the plugin window on the OpenCPN screen.
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The Auto, Standby and +/- buttons work as usual with your Evolution pilot.
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On top of this comes the Tracking button which is enabled only when a route is active.
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It will make you follow the active route as described above.
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Buttons are large for easy use on touch screens.
Turning at the waypoints
AutoTrackRaymarine will start the turn at a waypoint 1 second after passing the "Arrival Radius" of that waypoint. It will start turning relatively fast, where after it will seek the track towards the next (active) waypoint. This means that the behavior of AutoTrackRaymarine is influenced by the value of the Arrival Radius. Values of 0.03 or 0.04 nm are normally fine if waypoints aren’t too close together, some 0.5 nm at least. When waypoints are closer together, an Arrival Radius of 0.02 or even 0.01 nm may function better. But the behavior at a turn is also very much dependent on your boat.
The default arrival radius for OpenCPN can be set in Options→Ships→ tab Routes/Points. This default will apply to all new routes and waypoints defined. The arrival radius of a waypoint is found under Properties (of that waypoint) under tab Extended. Manually adjusting the arrival radius of all waypoints in a route is quite laborious. Quicker is: Export the route as a .gpx file. Open that file with a text editor and replace strings like: <opencpn:arrival_radius>0.040 with an identical string with another value. Don’t forget to save and import in OpenCPN afterwards.
Preferences
To access AutoTrackRaymarine preferences, access the context menu of OpenCPN. You find the context menu by clicking the right hand mouse button anywhere on the screen. There you select "AutoTrackRaymarine preferences". Alternatively the preferences window can be opened from the Plugin Manager. Go to the Plugin Manager in OpenCPN (Options→Plugins), select AutoTrackRaymarine and click Preferences.
In Preferences you can set the Max Correction Angle, that is the maximum correction that AutoTrackRaymarine will apply to the bearing to the next waypoint (BTW) to get back on the route segment. Setting this value too low makes it difficult to keep on track in case of cross currents. Setting Max Correction Angle to 30 or 40 degrees should normally be fine. Setting Max Correction Angle to zero will cancel all corrections on the BTW. Then the ship will head straight for the next waypoint, without getting back to the original route segment.
With Sensitivity you can adjust the amount of correction AutoTrackRaymarine applies to the BTW to bring you back on the defined route segment. Not enough action, increase to 100% or even higher. Unstable, rapid zigzagging, decrease to 70 or even 40%. Fast boats need lower values of Sensitivity.
By tagging "Logging On" you can activate the logging of this plugin in the opencpn.log file. Use this in case of abnormal behavior or errors. The resulting opencpn.log file can be used by the makers of the plugin to analyse an issue. But don’t turn logging on when not needed, the logfile can get very big.
Background
For the technically interested, the plugin is using a PID based steering algorithm that is using the XTE as control parameter. The algorithm continuously calculates corrections on the Heading Origin to Destination.
AutoTrackRaymarine normally sticks to the route within a few meters, on heading changes at waypoints it may overshoot a little. With large compass errors or strong cross currents, it may take a minute or so to settle down on the track.
Warning: this plugin may take full control of your autopilot. In case of system or software errors be ready to switch the autopilot off.