ST6001+ NMEA and HSB2 SeaTalk interface

[Greg Lee]

Hi,
First post to the forum and I’ll start with apologies for the length of this note. I’m attempting to put together a bit of a hybrid. We have two boats with Raymarine electronic gear. The one I’m writing about has a pristine, fully functional and cosmetically perfect Pathfinder radar/plotter (RL80C+), L1260+ plotter/sounder and a ST6001+ autopilot. I want to add an AIS transponder and have read all the posts here about why that's a problem so we are adding standalone equipment. We only have room for two displays and I love my Raymarine radar. It works flawlessly so am reluctant to retire the entire system. Since my current gear will not support AIS my plan is to retire the L1260+ and replace it with a computer monitor driven by a micro PC running Rose Point Coastal Explorer. It’s my preference to drive the ST6000+ using the PC and will therefore need to feed the AP course computer NMEA 0183 sentences from the PC to do so. The literature I have appears to so how to make that happen.
Here’s my question. Can I configure the RL80C+ as a backup source to drive the ST6000+? Can I leave the SeaTalk cable in place or do I need to isolate the two sources of autopilot data (PC and RL80C+) with a selector switch? Your thoughts and guidance are appreciated.
Greg Lee
Huntington Beach, CA

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Greg,

Q1. Can I configure the RL80C+ as a backup source to drive the ST6000+? Can I leave the SeaTalk cable in place or do I need to isolate the two sources of autopilot data (PC and RL80C+) with a selector switch?
A1. There should be no need for any switches as you have suggested. The NMEA 0183 output of the PC may be interfaced to the course computer's NMEA 0183 input port, to the NMEA 0183 input port of the autopilot control head, or to the NMEA 0183 input port of the RL80C+ display. Navigation may be commanded from either the PC or RL80C+, but may only be stopped/cancelled by the device which had commanded navigation.

[Greg Lee]

Simple, eloquent and easy to implement. Thanks for the guidance.
Greg Lee
Huntington Beach, CA

[Chuck - Raymarine - Moderator]

You're welcome.

[Greg Lee]

Hi Chuck,
Another question? I'm wiring the new AIS transponder. It has a dedicated GPS receiver/antenna. This particular transponder (Vesper XB-8000) connects to the ship's PC via USB. Data generated by the AIS and PC is mutiplexed and available via the transponder's NMEA 0183 output. It is my plan to feed this data to the ST-6000+ to command navigation via one of the methods you suggested. Here's my question. Can I leave the existing, Raymarine GPS connected? If so, how are conflicts between the Raymarine GPS and Vesper GPS reconciled (or is there even an issue)?
Your thoughts?
Greg Lee
Huntington Beach, CA

[Chuck - Raymarine - Moderator]

Greg,

Two points:

- The autopilot's NMEA 0183 port is exclusively designed to support 4800 BAUD NMEA 0183 communications. NMEA 0183 AIS communications required 38400 BAUD NMEA 0183 communications. As such, multiplexing data from the AIS transceiver with that from the PC will result in 38400 BAUD NMEA 0183 output from the multiplexer ... this cannot then be transmitted to the autopilot's NMEA 0183 port. The 4800 BAUD NMEA 0183 output from the PC alone should be interfaced to the NMEA 0183 input port of the autopilot.

- Raymarine equipment of the vintage specified is not designed to support more than one source for any specific data item COG, SOG, heading, latitude, longitude, etc. Correspondingly, care should be exercised when interfacing a second potential source of GPS data to the system (in this case the third party AIS transceiver). When doing so, it is recommended that the AIS transceiver be configured to not transmit GPS data via it NMEA 0183 interface.

[Greg Lee]

Hi Chuck,
Once again an incredibly helpful response. Not only did you answer the question I asked but you also answered a question I wasn't smart enough to ask!
As a result of your latest reply I have a new strategy. Don't use the 38,400 Baud mutiplexed NMEA 0183 out feed for the ST6001+ (which I very neatly wired and secured over the weekend - which is OK - practice never hurts). Procure a USB to serial port adapter and feed the ST6001+ with a 4,800 Baud AP-only set of NMEA 0183 sentences. Leave the Raymarine GPS in place to provide data to the Raymarine system, third party AIS and PC GPS provided by third party AIS-dedicated GPS. Default command navigation will be via PC, backup via Raymarine Pathfinder radar/plotter. Make sense? Any "watch-outs"?
Greg Lee
Huntington Beach, CA

[Chuck - Raymarine - Moderator]

Greg,

Your new approach sounds reasonable. Should you attach a system integration diagram of your proposed changes, then it may make things clearer for others creating a similar system utilizing a PC as part of their navigational system.

[Greg Lee]

Hi Chuck,
Sounds good. I just ordered a USB-to-serial adapter. Once I get it all up and running I'll pull together a schematic and send to you for comment before posting.
Thanks again,
Greg Lee
Huntington Beach, CA

[Greg Lee]

Hi Chuck,
I've not found the answer to having the AP connected to both the Raymarine Pathfinder radar and the new PC nav computer so for now the PC is driving the AP. I'll continue to pursue that but otherwise everything else is working as expected but for one objective. I'd like to display the ARPA targets on the PC. Do I need to export from the Pathfinder anything other than the TTM sentence?
Thoughts, guidance, suggestions?
Greg Lee
Huntington Beach, CA