711C "POSITION SOURCE ARE CHANGED" ERROR WITH TZT3

[neversink2]

My 711C AP screen recently started flashing and beeping with the error message "position source are changed". The lat/lon on the AP controller also began flashing.
I tried clicking through the NMEA2000 PGN outputs and the error goes away if I turn 12906 COG & SOG, Rapid update to "off". However, this removes the data from the AP. While toggling the 12906 on/off, i also saw the error "speed source are changed". The AP has the PG700 compass as source 1 and the MFD as source 2 for external data.

The only recent change to my system was a new thru hull B275 LHW thru hull transducer which the MFD automatically recognized. How do I fix this so the AP still gets data from the MFD without the error message?

Thanks in advance.

 

[neversink2]

Any help with this? I tried going into the setup menu and refreshing data sources, but it just keeps beeping. Very frustrating. Do I have to do a factory reset on the Autopilot?

 

[Johnny Electron]

Being your autopilot isn't the source of COG & SOG, I would wonder why you would turn it on to regurgitate delayed data back out to the 2000 bus. Normally about the only unique sentence the pilot has to offer a 2000 bus is Rudder. Why would the you set the MFD as the second source of heading in the settings? The MFD isn't a heading compass or valid source. Is the MFD setup to regurgitate heading as well? It seems like setup problems with data flow and sources are tripping you up somewhat. The MFD only needs the basic three PGNs on to run a pilot. It is a mistake to turn everything on or regurgitate data.

 

[neversink2]

I’m turning the data source on/off on the MFD…. Not on the AP. The error goes away when I turn off SOG and COG but then the AP loses it’s position data.

 

[Johnny Electron]

It is based on what setting sources and their priority order you have setup in the pilot data sources (priority). Normally installs will have a SCX20 or external GPS that offers better fix than using the internal GPS of the MFD. If the MFD is you only source of GPS then it should be ON along with Position data PGN. Then in the pilot setup under the sources you want to put the best and priority source of Position at the top line. (#1 priority) and the rest of the lines blank. Same for the SOG source. Then it won't be switching sources from whatever you have set as priority now and the MFD. When it switches sources among the chosen devices, it is normal to receive the notice that it is doing the switch to the secondary or back to the primary.

 

[neversink2]

Ok I fixed it... it was sort of along the lines of what you said. My 2nd bridge MFD had some NMEA2000 sentences turned on. Once I turned those off and the AP was receiving data from the chartmaster only, the error went away. I think the AP is set to AUTO for data sources, so changing the data source to the chartmaster only on the AP would have been another way to fix it... which is what you recommended. I also have a tower MFD but haven't checked that yet to make sure the NMEA 2000 data outputs are all turned off. Thanks for your help.