Raytheon/Raymarine SeaTalk-1 Issues on SO40
Jun 1, 2015 3:48:14 GMT
Post by so40gtb on Jun 1, 2015 3:48:14 GMT
One of the weekend projects was to complete the chartplotter-at-helm installation by interfacing the original ST60/ST6000+ instruments to NMEA 2000.
First off, Voyageur has always had an odd behavior pattern: the repeater instruments at the port helm and at the navigation station lose data unless the autopilot is powered up (but not necessarily engaged).
I gained access to the SeaTalk-1 wiring at the helms for an inspection. It was complete chaos at the starboard helm. After a few hours of flailing about, I decided to strip out the existing wiring beyond the Tridata and Wind instruments and re-wire as compactly as possible. Five surplus and/or "wires to nowhere" came out! Did I fix the autopilot dependency of the repeater instruments? Well, I recall testing and finding no issues on Friday. But on Saturday (in cold NE wind and rain), the aforementioned behavior was "back" (or maybe never left).
If the SeaTalk-1 bus is connected to the autopilot, but DC power is not provided to the latter, there will be no data transfer between the other SeaTalk-1 devices. Disconnect the bus at the autopilot (yellow wire) and the problem vanishes (along with any interface between the autopilot and other instruments, plus the autopilot not working). It appears that the unpowered autopilot "sinks" the data bus so as to render it inoperative.
The obvious fix: a relay with its coil (and damper diode) placed across the autopilot's DC input, with its contacts wired so that the SeaTalk-1 data bus is connected to the autopilot only when the latter has primary 12V supplied to it. I will implement this next weekend.
Why the fuss? I don't like the idea of being forced to keep the autopilot active in order to provide data to the repeaters. On long cruises, power conservation is paramount and even, when not active, the autopilot computer pulls charge out of the battery.
-Karl
First off, Voyageur has always had an odd behavior pattern: the repeater instruments at the port helm and at the navigation station lose data unless the autopilot is powered up (but not necessarily engaged).
I gained access to the SeaTalk-1 wiring at the helms for an inspection. It was complete chaos at the starboard helm. After a few hours of flailing about, I decided to strip out the existing wiring beyond the Tridata and Wind instruments and re-wire as compactly as possible. Five surplus and/or "wires to nowhere" came out! Did I fix the autopilot dependency of the repeater instruments? Well, I recall testing and finding no issues on Friday. But on Saturday (in cold NE wind and rain), the aforementioned behavior was "back" (or maybe never left).
If the SeaTalk-1 bus is connected to the autopilot, but DC power is not provided to the latter, there will be no data transfer between the other SeaTalk-1 devices. Disconnect the bus at the autopilot (yellow wire) and the problem vanishes (along with any interface between the autopilot and other instruments, plus the autopilot not working). It appears that the unpowered autopilot "sinks" the data bus so as to render it inoperative.
The obvious fix: a relay with its coil (and damper diode) placed across the autopilot's DC input, with its contacts wired so that the SeaTalk-1 data bus is connected to the autopilot only when the latter has primary 12V supplied to it. I will implement this next weekend.
Why the fuss? I don't like the idea of being forced to keep the autopilot active in order to provide data to the repeaters. On long cruises, power conservation is paramount and even, when not active, the autopilot computer pulls charge out of the battery.
-Karl
