August 30, 2008 12:24
I have had an issue with sudden course swings for some time when selecting goto and using the nav function on my autopilot to drive along a route. Things would be great for hours, then suddenly the boat would drive off 40-60° to port, then slowly correct. I have been emailing our esteemed expert to figure it out, but the solution is worth posting for anyone else who may encounter it.
The root problem is a NMEA feedback loop, which was suggested to me. It took me a long time and another problem to see what I had done wrong. Of course one should suspect any device that is connected to miniplex talker and listener ports. In my case that was a Furuno video sounder. It has been hooked up that way without problems for a long time. Furuno's NMEA output options can be a bit confusing though. The "off" option in the setup menus does not turn NMEA output off. It still gives the output, but only that output that is generated by the sounder.
I had taken my electronics out of the wheelhouse for winter. When I put them back I ran through the setup menu and knew that I needed the NMEA output to record depth and water temperature, so I turned NMEA output to "on." This is a rather counterintuitive way of naming the output options. Since I turned NMEA output off I have still been recording depth, but without any wild course swings. I only have one Furuno device on the boat, but I suspect that the company uses the same convention on other equipment.
I love the nav option and I'm greatly relieved to finally figure out how to get that laser straight action from the autpilot once again. Many thanks for the tech support help that gave the correct answer to my problems. It just took a while to see why it was correct.
The root problem is a NMEA feedback loop, which was suggested to me. It took me a long time and another problem to see what I had done wrong. Of course one should suspect any device that is connected to miniplex talker and listener ports. In my case that was a Furuno video sounder. It has been hooked up that way without problems for a long time. Furuno's NMEA output options can be a bit confusing though. The "off" option in the setup menus does not turn NMEA output off. It still gives the output, but only that output that is generated by the sounder.
I had taken my electronics out of the wheelhouse for winter. When I put them back I ran through the setup menu and knew that I needed the NMEA output to record depth and water temperature, so I turned NMEA output to "on." This is a rather counterintuitive way of naming the output options. Since I turned NMEA output off I have still been recording depth, but without any wild course swings. I only have one Furuno device on the boat, but I suspect that the company uses the same convention on other equipment.
I love the nav option and I'm greatly relieved to finally figure out how to get that laser straight action from the autpilot once again. Many thanks for the tech support help that gave the correct answer to my problems. It just took a while to see why it was correct.
Edmund