This week we have been helping one of our dealers; Marine Electronic Installations (MEI) in Portsmouth, to find a solution to an interesting NMEA2000 problem with the latest range of Raymarine a, c and e Series Multi-Function Displays.
Most of these MFDs feature an internal GPS, a SeaTalkNG (NMEA2000) interface and an NMEA0183 interface. Under normal circumstances, if you connect one of our AIT2000 or AIT3000 transponders to a Raymarine MFD via SeaTalkNG (NMEA2000) the MFD will use its own internal GPS as the position source and receive the AIS target information from the transponder.
What MEI discovered, was that when a Raymarine SeaTalk 1 to SeaTalkNG converter (E22158) is fitted to the network, that the MFD stops using its internal GPS and tries to use a GPS source on the SeaTalkNG network. As our transponders are outputting the Rapid Update GPS PGNs on the NMEA2000 network, the Raymarine sees this as a GPS source and tries to use it but then reports an “AIS Position lost” alarm because the GNSS PGN that provides GPS status information is not being received.
This seems to be a unique problem to Raymarine and not one, so far, reported on other systems. For instance the latest Garmin plotters always default to using their own GPS and ignore the GPS data from the AIS transponder. Also it only occurs when this SeaTalk 1 to SeaTalkNG converter is in the system, although this is quite a popular accessory and used when boats have older ST50/ST50+/ST60/ST60+ instruments or autopilots with a SeatTalk 1 interface.
We have found two ways to fix this problem;
1) Connect the AIS Transponder to the Raymarine MFD via NMEA0183, which is fine for units that have an NMEA0183 input (all units except a6X and a7X )
2) Send a special configuration command to the AIT2000/AIT3000 transponder via the proAIS2 software that turns off the NMEA2000 GPS data
For more information on this configuration command please email support@digitalyacht.co.uk
Hi
I wondor if you can help me
I have a Digital Yacht AIS transponder fitted along with a standard horizon vhf and a raymarine C95 plotter,all on a nmea 2000 network
Plotter is told to use it’s internal antenna
problem 1 …plotter AIS proximity alarm cannot be disabled,so AIS is not turned on whilst racing “round the cans”
problem 2 Due to no AIS gps signal on the network the standard horizon GX 2000 vhf sets off it’s deafening “NO GPS” alarm after 10 mins
I need my vhf on so whats the solution ?
Kind regards
Nigel
Hi Nigel,
The Standard Horizon GX2000e does not have an NMEA2000 interface, only a couple of NMEA0183 interfaces. Also on the most recent units Standard Horizon have changed the wiring slightly from what I used to create our Tech Note – I need to update this. The new wiring is as follows…
If you can double check how you have the AIT2000, GX2000e and c95 connected together, I would be more than happy to try and help you get rid of these irritating problems.
The proximity alarm is a function of the c95 and they do appear to give a method of turning this off, but they bury it away and call it the “SafeZone” alarm, which is used for both AIS and MARPA targets. You need to look for the “SafeZone” alarm ON/OFF function.
Hope this helps and if you can come back with a simple wiring diagram, I will try and advise further.