[CA] [CA11] Integrating Garmin GPS into Seatalk 1 network

[markgadson]

I'm currently in the process of integrating a Garmin 74CV GPS/Chartplotter into my existing Raymarine Seatalk 1 network which includes an ST6001 SmartPilot control head, S2 course computer, ST60 Wind, ST60 Depth and ST60 Speed. I searched the forum and instrument manuals and have come up with the attached 2-page schematic diagrams of my proposed connections. I would appreciate a review of the schematics to ensure that I am on the right track. Thanks in advance for your response and guidance.

Thanks!

Best regards,

Mark Gadson

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Mark,

Please note that no diagram has been attached to your thread. That said, as the 74CV features a NMEA 0183 output port, it would typically be advised that the 74CV's NMEA 0183 output port be interfaced to the S2's NMEA 0183 input port or to the NMEA 0183 input port of the ST6001 autopilot control head. When so interfaced, the autopilot's Track mode feature may used after having commanded the chartplotter to go to a waypoint / cursor position or to follow a route.

[markgadson]

Chuck,

So sorry about the attachment! I forgot to hit the add attachment button after I chose the file.

I hope you will can open the attached 2-page attachment and review my diagrams. Thanks again for your help and guidance.

Best regards,

Mark

[Chuck - Raymarine - Moderator]

Mark,

It would not be recommended that the NMEA 0183 output of the S2 autopilot course computer be interfaced to the 74CV GPS/Chartplotter or a NMEA 0183 data loop may result. Should the 74CV GPS/Chartplotter have some control over which NMEA 0183 sentences will be received, then switching off all sentences except for those containing heading, rudder, and instrument data would be recommended. Alternatively, a programmable NMEA 0183 multiplexer (ex. Actisense NDC-4) may be installed between the autopilot course computer's NMEA 0183 output port and the 74CV GPS/Chartplotter's NMEA 0183 input port.

Please additionally note that the S2 feature two SeaTalk ports. One should be used to interface the instruments to the S2 and the other should be used to interfaced the autopilot control head alone to the S2. All three lead of the SeaTalk cable connecting the autopilot control head should be used, while only the data (yellow) and ground (shield) leads of the SeaTalk cable connecting the instruments should be used. When so interfaced, the autopilot may be used irrespective of the power state of the instruments. The additional separation may provide a degree of isolation should a device suffer a failure of its SeaTalk communications circuitry. When such SeaTalk failures occur, they may block communications within the entire SeaTalk bus.

[markgadson]

Chuck,

Thanks for the guidance. Based on your input, I have attached revised schematics for your final review. Hopefully, these accurately represent your comments. I look forward to receiving any final thoughts.

Best regards,

Mark

[Chuck - Raymarine - Moderator]

Mark,

Your updated diagram now appears to be correct.

[markgadson]

Thanks so much Chuck! As always, your expert help is appreciated.

Best Regards,

Mark

[Chuck - Raymarine - Moderator]

You're welcome.