AP magnetic heading not matching TZT3 heading.

[allrelative]

My AP magnetic heading is inconsistently off by 20 degrees on AP compared to SXC20 On TZT3, Makes integration with AP > TZT3 inconsistent and cannot use.

I have a
TZT3 connected to NMEA 2K
TZT3 NMEA 0183 out- not connected.
PG500R connected to Nav pilot 511 in compass port
Nav pilot 511 connected to NMEA 2K backbone via IF-NMEA2K2, NMEA IN/OUT
SXC20 connected to NMEA 2K

Would like the AP to get its heading from the TZT3 OR from NMEA2K2.

Thanks for any and all help.

 

[Johnny Electron]

It sounds like it is related to either the two diffrent source of heading you have or something with Magnetic variation. I would recommend the following.

-Remove PG500 for troubleshooting
-Ensure that pilot is reading the SCX20 heading data
-Ensure that the TZT3 is NOT putting out heading data to the 2000 bus via PGN (It is not the source of heading and data flow is important)
-Ensure all units are setup for Magnetic heading display
-Compare Heading on all units with the steering compass and COG when moving straight.

Does everything match then?

 

[allrelative]

Thank you very much, I was reading an older thread and thought I needed the another feed ?

"
The right way to do it would be to get another IF-NMEA2k2 i"nstalled on the 2000 bus and set it to high-speed heading mode. I would remove the older PG500 and wire the 0183 data from the converter where the PG500 was and change the baud rate appropriately. This will provide the pilot very fast and high quality heading. You will need to change the heading source under "Sea Trial" to "OTHER" instead of PG500. You can't use the existing converter because with normal mode the heading data is coming too slow. You can't change it because you need that existing one to provide the steering instructions to the pilot. "

 

[Johnny Electron]

The other thread is most likely correct if you want the pilot to have the full advantage from the SCX20. The converter in normal mode won't provide fast enough heading to make the pilot happy but you should at least be able to get all your sources lined up and clear any MAG VAR issues on the setup. You could then put the PG500 back for the pilot to use as long as you can line it up properly with the other heading. Overall, I don't recommend. I would do like the other thread talked about.

 

[allrelative]

Thanks , this did the trick

The fix was to add another IF-NMEA2k2 2000 bus and set it to high-speed heading mode (cut orange wire), connect to the heading port on AP
Remove the older PG500 and wire the 0183 data from the converter where the PG500 was and change the baud rate appropriately.
This will provide the pilot very fast and high quality heading.
Change the heading source under "Sea Trial" to "OTHER" instead of PG500.

 

[Johnny Electron]

:jump :jump