[DG] [DG11] Heading from legacy AP

[Dan G]

Our system is a mix of Seatalk and Seatalkng, with an ST-STNG junction box. On the ST side, we have a Type 100 AP, plus some ST-60s. On the STNG side, we have a P70 and an eS MFD. Recently, we lost heading information. The P70 showed - - - as heading, and the heading on the MFD and ST-60 Multi was not at all related to the steering compass heading. I ran the Fluxgate Compass test and found resistances to be in range. A new Fluxgate didn't resolve the problem, either.

I ran a buffer capture on the MFD. It appears that heading frames are being broadcast on the STNG bus by the junction box, but I can't decode the data field. Does the following PGN contain valid heading info?

Rx 272196 9 f1 12 73 0 b7 1f ff 7f ff 7f fd

Vessel was pointing roughly NNE.

Based on that, what do you suggest as a next step?

[Derek - Raymarine - Moderator]

Hi Dan G,

Thank you for your enquiry.

Assuming that the compass heading on the Autopilot control head is also incorrect, then the course computer would appear to be the root cause, since you have eliminated the fluxgate compass as the cause.

However, one last check would be the rudder reference unit, do you have one fitted and connected to the Type 100 course computer? If no, then the Type 100 has a fault.

if you do have a rudder reference unit connected, then check it's operation when the Autopilot is in STANDBY mode, you should see the rudder angle follow the movement of the rudder as you turn the steering from Port to Starboard. if it is correct, then the Type 100 needs repair/ replacement, if however the rudder display is erratic or simply incorrect, then possibly this is the fault, ( since both the rudder reference transducer and the compass use the same A to D converter in the Type 100 computer). Disconnect the rudder reference unit and check the compass again.

regards

Derek

[Dan G]

Thanks, Derek.

I'm still curious about that PGN. Is is this a "No Heading" message or just a false reading?

Assuming it's the ADC in the T-100, is there any reason why I can't install an EV-1 compass, configure it as heading source in all connected STNG devices, and continue to use the the T100's pilot functions?

[Tom - Raymarine - Moderator]

Hello Dan,

I wouldn't normally chip in on a thread like this, but since I'm a sucker for seeing hexadecimal in a post: your posted message decodes as 046.5 degrees Magnetic (as you say, roughly NNE.)

Regards,
Tom

[Louise - Raymarine - Moderator]

Hi Dan,

Thank you for your post.

The type 100 course computer will not be compatible with the EV1 heading sensor, if a new fluxgate and the functioning old one did not resolve the issue the problem indicates a faulty Type 100 course computer.
We no longer stock any spares for the Type 100 course computer due to its age, therefore are unable to offer a repair service.

It is worth calling some local dealers who may still offer a test and repair service on the T100 course computer.

Many Thanks
Louise