[CA] [CA11] Using legacy seatalk power supply for STng backbone

[riclevitt]

my system includes legacy depth and speed, st60 wind, 4000autopilot,ES75 and 100remote connected through ST-STng 5 plug adapter, and legacy st80 multidisplays.
I am in the process of upgrading the autopilot to EV1 with P70 display. I am not sure exactly where the power supply is connected to the legacy system but everything works fine.
My question is if I can continue to power the network through the existing power supply or if I need to power into a new white spur connection. Id rather not if I do not have to.

[Chuck - Raymarine - Moderator]

riclevitt,

While it is technically possible to backfeed power from a SeaTalk bus via a SeaTalk to SeaTalkng Converter Kit to power a small SeaTalkng / NMEA 2000 backbone, it is not considered a best practice to do so. This recommendation is based upon the understanding that SeaTalkng / NMEA 2000 communications protocol has overtaken SeaTalk for communications within Raymarine products. As with the Evolution autopilot and eS75 MFD, new additions and replacements within the system will likely have a SeaTalkng / NMEA communications interface rather than a SeaTalk communications interface. As more items are added to the backbone, the power demands of the backbone will increase, causing the current draw though the SeaTalk to SeaTalkng Converter to increase, potentially beyond the limits which the SeaTalk to SeaTalkng Converter was designed to handle. For this reason, it is recommended that when adding new equipment to a backbone such as your that one head the recommendations of the FAQ addressing this subject.

Please additionally note that the SeaTalk to SeaTalkng Converter has not been designed and tested for use with ST80 products.

[riclevitt]

Chuck,
Got to the boat this weekend found and disconnected the old seatalk 1 power supply from the bus and added 12 v to a white spur in the st-ng converter so that I am no longer back feeding. This shut down power to all my instruments. Can I keep the old power supply and also keep the new powered spur for the Evo autopilot and p70 which I will install?
Thank you
Richard

[Chuck - Raymarine - Moderator]

Richard,

When properly installed, the SeaTalkng backbone (via the ST-STng Converter) should be supplying power to the SeaTalk bus. If disconnecting power the SeaTalk bus now prohibits your instruments from powering ON, then there would appear to be a fault with your installation. Please attach a system diagram (a photo of a hand drawn diagram will suffice) to a response to this thread for further analysis. The diagram should show each device and how it has been interfaced to the system.

[riclevitt]

Chuck, Found my stupid mistake this weekend. Yellow from ST-STng converter went to my RF remote for autopilot instead of the bus. Fixed the problem and works fine.
Though not tested by Raymarine, legacy ST80's work fine as well.
Thanks for your help
Rich

[Chuck - Raymarine - Moderator]

You're welcome.

[riclevitt]

I have disconnected my st power supply and am adding a new one through an empty spur on my st-stng converter. I have a 12 guage supply direct to the breaker that used to power my old 4000 wheel pilot and now goes to my ACU100. It would be most convenient for me to to simply split this supply, and add a fuse to power my backbone.
Question is whether this permissible or must I wire all the way back to the breaker. The breaker terminal would be a bit crowded with 3 leads including the ES75.

[Chuck - Raymarine - Moderator]

Rick,

There is nothing technically wrong with powering the SeaTalkng / NMEA 2000 backbone in the manner which you have suggested. Bear in mind, that unless a switch is installed within the circuit supplying power to the SeaTalkng / NMEA 2000 backbone, it will not be possible to separately control power to the SeaTalkng / NMEA 2000 backbone. While having such capability is not required, it is considered to be a best installation practice.