Seatalk2 to seatalkng for classic series MFd

[phorvati]

I bought a used sirius weather receiver with all the cables. SR50. It came with seatalk ng to seatalk2 raymarine cable that has a wye in it for power. See attached pic.
So I confirmed everything works but I cannot use the Wye cable at the pedestal because it won't fit through the stainless pedestal guard tubing. I have a Seaview mount and things are tight.
So I bought a used seatalk2 cable which I was able to snake through. And I also bought a stalking to seatalk 2 pigtail which I cut off in order to make a splice. So with the new setup SR50 LED indicates no seatalk ng. For splicing I used attached document as refference. Power ground and shield I spliced on ring terminals on a terminal board. For Data +/- i used buttsplice as I believe distorts characteristic impedance less. So I guess I will buzz out the cable to make sure it's connected, but beyond this, does anyone know if there is anything special in that wye cable?

[marty9876]

I did this same install however I kept everything Seatalkng. I’ve found the C80 to be very picky on seatalkng traffic, basically only accepts SR50 traffic as if I connect my Vespar to feed it AIS data everything stops workin and I confirmed this via Raymarine forums.

Few notes - Seatalkng needs to be properly terminated on each end, I used a backbone kit and a tee at the plotter with a terminator. Power is injected via backbone kit connector. Also be sure to update the software of the plotter assuming it’s a C80 - v5.14 I think it might be (?) - later available. Pretty easy update process but I’m a computer geek.

I’m sure you can splice things together and save a buck, I choose not to go that route. By in large it works fine.

[phorvati]

Originally Posted by marty9876

I did this same install however I kept everything Seatalkng.

Could you elaborate on this? I don't have any other Seatalk2/SeatalkNG traffic or NEMA 2000 traffic. Everything else is Seatalk1 or NEMA183. So SR50 is the only SatalkNG traffic and it connects to Seatalk2 on the back of MFD. That should simplify operation.
Originally supplied wye cable connects to 5 pin Seatalk2 connector on the back of classic C series MFD. And when i connect SR50 to my classic C70 with that wye cable, everything works.

I am going to check if by some chance that wye cable has terminators built-in, and the individual pigtails that I bought did not. By check i will ohm out between Data+/Data- for 120hms

Other than that shouldn't termination happen inside MFD? and inside SR50?
i don't know. you got yours working and mine is not so once i exhaust my options i'll have to consider going with the backbone kit and a tee at the plotter with a terminator. I dont think there will be room to put a Tee inside seaview housing. Its packed as it is.

[marty9876]

I’ve got a C80, not sure how applicable this is to a C70.

I had the same issues with the supplied cables not fitting in the metal tubes to the plotter and not being long enough. The original plan was to install Seatalkng network for the SR50 and my AIS so I did the backbone kit plus it fit in the metal tubes. Turns out the C80 can only accept/process AIS traffic via NMEA 0183. So yea, I now have a Seatalkng network just for the SR50.

Long term my thoughts are to get the kits to convert the analog instruments and NMEA 0183 traffic to Seatalkng so I can work with that data across iPads and alike. I’m hoping (?) I can convert and haul the AIS data from 0183 up to the plotter via Seatalkng and convert it back. Seems messy.

I did the install last year so I might be missing some if the details, most confusing part is the C80 is very picky on which inputs which type of traffic comes in.

[phorvati]

All C series classic displays have the same connections. i believe 70 80 120 difference is just the screen size. See below. So you connected yours to Seatalk 2 port. which is really seatalk NG.
So it is interesting that you needed a terminator to get it working. Did you try with original wye cable?
it might be that my issue is termination. another might be a small section of un-shielded twisted pair where I did a butt splice or that the two shields might not be connected at the splice.

[Pizzazz]

I have a complete C80 system with an X5 autopilot. The y-cable that comes with the SR50 is just a nmea2000 cable with built in 60 ohm resistor. You do not have to use it. You can use any properly terminated Nmea2000 network with 120 ohm resistors on the ends. The C80 will accept the following Nmea2000 traffic:
SR50 weather
Wind/speed/depth/temp data
Heading data from compass
Position data from a Seatalk2 gps
Seatalk2 keyboard
Autopilot control

You will need to use the nmea0183 connection for AIS and for a NMEA 0183 gps data

It is best to use the Seatalk2 connection for heading data as this allows fast heading that you need for the radar overlay.

SV Pizzazz

[marty9876]

Originally Posted by phorvati

All C series classic displays have the same connections. i believe 70 80 120 difference is just the screen size. See below. So you connected yours to Seatalk 2 port. which is really seatalk NG.
So it is interesting that you needed a terminator to get it working. Did you try with original wye cable?
it might be that my issue is termination. another might be a small section of un-shielded twisted pair where I did a butt splice or that the two shields might not be connected at the splice.

Yes, when originally testing I wired things up in the cockpit via the original cables. I thought about splicing into the original cable but with my long term plans at the time I thought I could benefit form a full Seatalkng network.

[phorvati]

Originally Posted by Pizzazz

I have a complete C80 system with an X5 autopilot. The y-cable that comes with the SR50 is just a nmea2000 cable with built in 60 ohm resistor. You do not have to use it. You can use any properly terminated Nmea2000 network with 120 ohm resistors on the ends. The C80 will accept the following Nmea2000 traffic:
SR50 weather
Wind/speed/depth/temp data
Heading data from compass
Position data from a Seatalk2 gps
Seatalk2 keyboard
Autopilot control

You will need to use the nmea0183 connection for AIS and for a NMEA 0183 gps data

It is best to use the Seatalk2 connection for heading data as this allows fast heading that you need for the radar overlay.

SV Pizzazz

Thanks. I ill pursue the termination route and see if network comes up. i dont have any other nmea 2000 devices. GPS comes on seatalk 1 from raystar RS125. AIS comes on NMEA183. Everything else comes on Seatalk1. Im ok for now how it works. Not sure what you mean by radar overlay. I am using RD218 and I generally use side by side view of radar and charts when i use radar. AIS targets come up on both.

[Pizzazz]

Originally Posted by phorvati

Thanks. I ill pursue the termination route and see if network comes up. i dont have any other nmea 2000 devices. GPS comes on seatalk 1 from raystar RS125. AIS comes on NMEA183. Everything else comes on Seatalk1. Im ok for now how it works. Not sure what you mean by radar overlay. I am using RD218 and I generally use side by side view of radar and charts when i use radar. AIS targets come up on both.

When you overlay radar on the chart in one window (vs. side by side), the display needs accurate and fast heading data to keep the radar overlay in sync with the chart. It also helps with MARPA targets. If you think about it, the radar paints the target once every 2.5 sec. In this period the boat moves. If you use a fast heading sensor at 10 Hz, the display can calculate targets and overlay data more accurately. If you feed the display heading data via Seatalk 1, the refresh rate is limited to 2 times a second. So there is a lot more guesswork and everything is less accurate. You can send fast heading data (10 Hz and above only via nmea 0183 (difficult, you need a multiplexer and it slows down while waiting for other data) or Seatalk 2. Hence most systems suggest fast heading data be fed via Seatalk 2 or nmea2000.

SV Pizzazz

[phorvati]

I got it working. What ended up happening is that the Wye cable had built in terminators at each end. 120 ohm resistors. So in order to get it working I soldered 120 ohm radial resistor on the interface board of MFD. And I added a 120 ohm at the SR50 end down in lazarette. I added it to the splice terminal. So cables I got on ebay were proper in terms of mechanical fit and connectivity but lacked the termination for the CAN bus.