Troubleshooting a SeaTalk communications failure

[Chuck - Raymarine - Moderator]

Troubleshooting a SeaTalk communications failure

SeaTalk communications failures (STLK FAIL) as reported on an autopilot's control head, ST60 Wind Instrument's LCD flashing two square boxes, or cessation of SeaTalk communications between all products, may occur as a result of any of the following:

- insufficient power due to depleted / degraded vessel batteries ... connect the vessel to shore power and fully charge the vessel's batteries. Upon completion of charging and while still connected to shore power, test communications between devices which have been interfaced to the SeaTalk bus.

- insufficient power due to line loss within SeaTalk bus ... in larger SeaTalk busses, sufficient line loss may result to reduce power below that which the SeaTalk communications circuity within the connected devices may operate. This may be overcome by installing more than one power insertion point within SeaTalk bus. Each power insertion point must be powered from the same 12 VDC power circuit and should be protected by a 3A fuse.

- insufficient power due to having joined the red lead of the SeaTalk cable interfacing a C/E-Series Classic MFD to the SeaTalk bus ... this problem is most commonly identified in systems which feature these MFDs and either use an autopilot or dedicated circuit to power the SeaTalk bus. In such systems, should the autopilot course computer or SeaTalk bus power not be switched ON when the the C/E-Series Classic MFD(s) is in the ON power state, then insufficient power will be supplied to the SeaTalk bus, resulting in SeaTalk communications failure. The problem may be eliminated by disconnecting the red lead of the SeaTalk cable which is interfacing the C/E-Series Classic MFD to the SeaTalk bus. The cable's red lead should then be insulated to prevent shorting.

- incorrectly wired SeaTalk bus ... while SeaTalk cables feature press-fit plugs or twist-locking plugs, spliced SeaTalk cables or terminals strips are commonly used to join devices to the SeaTalk bus. When joining SeaTalk Cables using splices or terminal strips, one need simply match leads of the same color (red to red, yellow to yellow, and shield to shield)

- failure of the SeaTalk communications circuitry within one or more device which has been interfaced to the SeaTalk bus.

In cases of SeaTalk communications circuitry failure, the device(s) having faulty SeaTalk communications circuitry may be identified through basic fault isolation. Accordingly, it would be recommended that the SeaTalk bus be reduced to two devices (ex. MFD and Raystar 125 GPS Sensor, autopilot course computer and autopilot control head, etc.) and upon verification that the two devices are communicating with one another, a third device would then be added to the SeaTalk bus. Should addition of the third device result in cessation of SeaTalk communications, then that device would be removed from the SeaTalk bus and the device would either be replaced or sent to Raymarine’s Product Repair Center to be bench checked / serviced. Should addition of the third device not result in cessation of SeaTalk communications, then additional devices will be added one by one to the SeaTalk bus and communications verified until SeaTalk communications with each device has been verified. Similarly, should the addition of any device(s) result in cessation of SeaTalk communications, then that device(s) will be removed from the SeaTalk bus and either replaced or sent to Raymarine’s Product Repair Center to be bench checked / serviced.

RAYFAQ#