[CA] [CA11] C80 Classic and "No Heading"

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Wings,

Q1. What if a system doesn't have an autopilot? How does the system acquire heading? Surely it's from the GPS.
A1. Negative. The Raystar 125 GPS Sensor is not capable of supplying heading data to the system. This GPS would only be capable of supplying the system with position, COG, SOG, date/time, and other data associated with the GPS position FIX. Please note that when properly interfaced to a SPX-30 autopilot course computer, the MFD would have been interfaced to SPX-30 autopilot course computer not only by SeaTalk, but also the NMEA 0183 output port of the SPX-30 would have been interfaced to the MFDs NMEA 0183 input port to supply the MFD with 10Hz stabilized heading data in support of the MFD's heading dependent features (radar overlay, MARPA, etc.). Please note that the MFD's NMEA 0183 output port should not additionally be interfaced to the autopilot's NMEA 0183 input port if both the SPX-30 and MFD are interfaced via SeaTalk or a data loop will be created. Should the MFD have been interfaced to the SPX-30 via SeaTalk communication alone, then the MFD would have only received 1Hz heading data updates from the autopilot system.

Q2. Since, in our system, the Autopilot and the C80 aren't connected via ST, then regardless of how the SPX30 is acquiring the heading data, I don't understand how it can be transmitted to the C80. Except when it's not, the C80 displays heading information with the SPX30 disconnected.
A2. See the response to Q1. One may easily verify whether this is so by temporarily configuring the MFD's NMEA Port Setting to NAVTEX 9600 (severs possible 4800 BAUD communications with the MFD), switching the entire system OFF, and then switching it ON again. Should the MFD then report a value within its Heading data item (vs. ---), then another source of heading data has been interfaced to the system which you have not yet identified.

Q3. Another interesting point is this. At this moment, the Autopilot is on and steering perfectly: it's still an independent system. We are running on a magnetic heading, so the fluxgate must be functioning, and we've never encountered problems with steering by magnetic heading. The C80 is operating perfectly and seems to have heading information: We are not receiving the "No Heading" system alarm. On the other hand, we cannot use the display choice of, "Heading Up", but only "Course Up", and "North Up". Should this mean that the C80 doesn't have heading information?
A3. Chart orientation changes may be blocked if the Chart application's Chart Sync feature has been configured ON. It is correspondingly recommended that you ensure that this configuration setting has been switched OFF

Q4. There is certainly a ghost in the system but I'm not sure what it is. The system alarm is the problem, of course, since it's persistent and overrides C80 function until the "Acknowledge" button is pressed.
A4. The persistence of heading is either due to the having additionally interfaced the SPX-30 to the MFD via NMEA 0183 communications or as has been previously specified, another source of heading is present within the system. The persistence of heading data would in no way be attributable to a problem with the MFD's circuitry.


Q5. Should we send in the C80 for repair? What would be the failure to mention?
A5. Negative. See the response Q4. Please additionally note that Raymarine's Product Repair Centers can no longer service C-Series Classic MFDs. That said and as indicated within the response to Q4, the persistence of heading data would in no way be attributable to a problem with the MFD's circuitry.

Q6. Should we purchase a new GPS mushroom? Is that the failure point? Can it be repaired? The unit sometimes requires 4-5 minutes for a fix, even when we're in the same location that we de-powered the ST bus that powers the GPS.
A6. As indicated, the GPS sensor would have not bearing upon the population of the Heading data item within your system. However, the slow GPS FIX acquisition may be indicative of a depleted CR2032 memory battery which may be fairly easily replaced. This memory battery is responsible for retaining almanac and last position data when the system is shut down, permitting quicker GPS FIX acquisition upon startup. Should you opt to replace the GPS sensor, then please click here to view a FAQ addressing this subject.