[DG] [DG] "No Pilot" message

[Wings]

We are in Rarotonga, Cook Islands and had to hand steer for a few days when our Raymarine autopilot failed and we had no wind.

ST8002 display head, SPX30 controller. It's worked for flawlessly for 8 years and no changes in wiring other than environmental degradation in heat in South Pacific. Used terminal strips for Seatalk 1 connections. The system has worked until one day it stopped working and displayed the message, "No Pilot", then "Seatalk Failure".

Thinking it might be wiring-related, I used a fresh, out-of-the-package Seatalk cable with 3-pin head on one end and bare wires on the other. I removed the SPX30-to-ST60 Seatalk cable (the one in place all of these years) from the left-hand Seatalk bus on the SPX30. (Right hand bus wiring goes to Seatalk terminal strips.) I replaced it with the new Seatalk cable, directly from the SPX30 to the ST60 but received same message. It's not the wiring since all old wiring was bypassed in this test and the results were the same.

No fault lights show on SPX30. Red power light and 12V light show on SPX30 when it's powered. Display red and shield work since display head is powered. It's that damned yellow wire again, the bane of my life.

There is no reason to think that the SPX30 or display head have suddenly failed, I don't think. I just have no way to test anything else but do need the system to work if possible.

Testing "yellow wire" problems is always difficult since I can't determine if the data is being transmitted. Is there a voltage check for this as there is in the r28170 diagnostics?

[Derek - Raymarine - Moderator]

HI Wings

Thank you for your enquiry.

NO PILOT and ST FAIL is related to the loss of comms around the network, as I suspect you know already. The key to getting to the bottom of this is to isolate parts of the system, as soon as you isolate the offending cable or connection or unit,the network will recover.

I would divide the network into chunks and independently power them this will identify the section where the fault is located. Then you can home in on that section and isolate the unit or issue that is the cause.

A usefull test is to turn the lights on- on one of the displays and the lights on the other displays will also come on - this will confirm the SeaTalk bus is up and running OK.

There is no specific test for SeaTalk, the lights test works well though.
thanks
Derek

[Wings]

YOU DA MAN, DEREK!

Thank you so much for the fast response, clear and concise. I understand. I was unaware that the ST network of other instruments could effect the ST SPX30 to ST8002 connection. My first step should be to disconnect the SPX30 from the general ST network. That should isolate it from other ST issues, and it should fire up. Am I correct? Operating the AP as a standalone still beats hand steering.

Yes, I have realized that I need to isolate the various instruments and rejoin them to the network one at a time. I've got a spare terminal strip and it's an easy process. It's uncomfortable but easy. I plan on disconnecting only the yellow wires, one at a time. Should I disconnect power, too? I wouldn't imagine so, but I will with your advice.

Again, thank you very much for your help. I feel that we can manage this but needed guidance.

[Wings]

Hello, Derek,

Your suggested solution for the autopilot was spot-on. I disconnected the SPX30-to-Seatalk-bus cable and the autopilot system is now functioning correctly, as before. It behaves as a standalone unit, but that's entirely acceptable. Thank you for your help.

Once the SPX30 was disconnected from the other instruments (Classic C80, ST60+ Wind/short arm transducer and ST+Graphic Display) some of the ST problem in these other instruments disappeared. We could again "see" more types of information on the graphic display, for instance. This seems to imply the problem was in the AP system, and that's disconcerting. Should I suspect a fault in the autopilot system itself, or in the connection between the AP system and the Seatalk bus?

I'm taking the liberty of asking another question related to these others. Our venerable C80 MFD works well but position and heading functions are still misbehaving.

We have read the C80 manual and have learned that the GPS sends heading and position information to the C80. With position data only, the C80 displays boat position as a solid black dot, and with heading provided, too, the vessel is presented as a ship icon. Our C80 is now losing the heading information that's provided by the GPS. In other words, we see a black dot in the correct location, but not a ship icon. In addition, the Graphic Display does not display a heading.

The C80 does display the COG, though, and that's being forwarded to the ST bus since it displays on both the C80 and our Graphic Display. No heading, but COG. We have both a numeric COG read-out and a two-arrow green vector. We do not have a one-arrow heading vector. How can the GPS or C80 find the COG and not know the heading? The manual is quite specific that the GPS provides position and heading information. Is COG is being "derived" by the C80 by looking at position information only (i.e. without heading information) at two different times?

Our reading of the C80 manual and our experience tell us that heading is the direction the boat's bow is pointed, while COG is the direction the boat is traveling over the ground, a GPS-based value. Are we wrong in that understanding? How is the heading information being generated?

I've cleaned and returned the GPS yellow data wire on the ST bus, but it didn't help. Periodically, the C80 "No Heading" alarm sounds, and the ship icon changes to a dot. Periodically, the "fix" icon in the upper right changes to "no fix" and our position disappears from the screen.

I have captured the GPS data stream but don't know what I'm seeing other than our Lat/Long, evident in the GPS sentence. I've enclosed an image.

We're at a loss on the next step. If you discern that the GPS is failing, and I think that it's possible since we're using losing position and heading data, can we use the info from a standalone AIS system? Shouldn't the sentences be usable by the C80?

Thanks for the help, as usual.

[Derek - Raymarine - Moderator]

Hi Wings
Thanks for the update.

The fact the SPX30 works OK now on its own and the restof the system works on its own suggests the interconnecting cable is the likely culprit, OR there is a data loop and by disconnecting the SPX30, you have removed the dataloop.
Try is different cable between the two systems, if the fault returns, suspect a data loop or some form of earth / groundloop which is triggered by the connection. soundslikje you are nearly there though.

With ref to the C80. with no heading info from the SPX30, while the boat is stationary the boat's position willbe a round dot, this should change to a boat shape once you are underway because when you rely on GPS COG for heading, this is unreliable under 1.5kts and so the boat position is defined as a dot until the SOG has climbed to a number above 1.5kts and COG becomes a reliable indication of boat heading.

Note that Heading is derived from the SPX30 compass,whereas COG is output from the GPS sensor, the two are not related.

If with the SPX30 disconnected from the C80 you are losing COG and NO FIX appears on the C80, then yes- you have a GPS antenna problem.

If you have reconnected the SPX30 and intermittantly getting NO FIX or loss of heading, there is stillan issue in the SeaTalk connection between the SPX30 and the rest of the system, as described at the top of this post.

Thanks
Derek