Using NMEA 0183 compass data of autopilot on OpenCPN

[Odysseus7]

Hello,

I have a Sitex 120SP autopilot that has an NMEA 0183 connection with the PC: Going from the pinout shared by Sitex to an RS232 connection to USB on the PC. I believe (if I am not mistaken) I set up the connection right; and the debugger seems to show the compass data flowing in. However, OpenCPN still does not orient the "boat icon" to the said compass direction. Am I doing something wrong, or missing something? Image enclosed.

Thank you.

[markcouz]

I'm no specialist so just making a suggestion - if you go to (setup>display>units) there is an option to select Show True or Show Magnetic headings....

[.Paul.]

Originally Posted by Odysseus7

Hello,

I have a Sitex 120SP autopilot that has an NMEA 0183 connection with the PC: Going from the pinout shared by Sitex to an RS232 connection to USB on the PC. I believe (if I am not mistaken) I set up the connection right; and the debugger seems to show the compass data flowing in. However, OpenCPN still does not orient the "boat icon" to the said compass direction. Am I doing something wrong, or missing something? Image enclosed.

Thank you.

The checksum is missing from the each magnetic heading shown in the NMEA Debug Window. Here is the first line:

20:33:18 (Serial:COM10) $APHDM,115.60,M<0x0D><0x0A>

The checksum should be an asterisk followed by two hex-digits. This should follow the letter "M". You can see checksums near the end of each GPS message line on COM12.

You might try removing the checkmark before "Control checksum" for DataPort COM10.

Don't change the "Control checksum" for COM12.


Paul

[captainjim47]

A "compass" data sentence from a GPS unit which only updates a few times a second is insufficient for modern autopilots to steer by... they require a gyro or a GPS unit that reports at least 10 times a second or the current state of the art at close to 20/sec., yes that means nmea0183 won't work. You can't steer to GPS, can't expect your a/p to either.

[hoolie]

I think the OP was concerned about heading data coming the other way. That is from the autopilot to OpenCPN

[Odysseus7]

Originally Posted by hoolie

I think the OP was concerned about heading data coming the other way. That is from the autopilot to OpenCPN

That is correct. From the electronic compass of the Sitex autopilot system to the PC.

[Odysseus7]

Originally Posted by .Paul.

You might try removing the checkmark before "Control checksum" for DataPort COM10.

Don't change the "Control checksum" for COM12.


Paul

Paul, many thanks for your great advice. Tried this, and it works!

[Moo]

Originally Posted by captainjim47

A "compass" data sentence from a GPS unit which only updates a few times a second is insufficient for modern autopilots to steer by... they require a gyro or a GPS unit that reports at least 10 times a second or the current state of the art at close to 20/sec., yes that means nmea0183 won't work. You can't steer to GPS, can't expect your a/p to either.

Nmea0183 works fine at 10Hz... Gyro or satellite compass data is usually fed via N0183....