Garmin GPSMAP 723 MARPA Target Lost

[caleroific]

I have recently updated my old Garmin 3010C plotter to a Garmin 723. This has meant reconfiguring my network from legacy NMEA 1083 to NMEA 2000. I have a Garmin GMR18 Radar and derive my Fast Heading from a Raymarine EV1 Sensor. Everything is working well other than when trying to acquire a MARPA target. When I attempt to acquire the target it immediately shows as being lost and is not tracked.

The problem points to unreliable Header Data being received by the Garmin 723.

With my old plotter MARPA worked OK. The only difference now is that the EV1 heading data which used to be fed via an Actisense NGW-1 SeatalkNG to NMEA 0183 Converter is now fed directly to the 723 via my SeatalkNG/NMEA 2000 backbone.

I have checked my NMEA200 backbone power supply and terminators. I have also tried isolating other sources of heading e.g. from my AIS transponder and legacy Garmin GPS17 but with no success.

Any ideas?

 

[PaulRainbow]

Cannot see the backbone pdf

 

[caleroific]

Cannot see the backbone pdf

Thank you. I've changed it to a jpg. Should be visible now.

 

[Sandy]

What is a Fast Heading?

 

[PaulRainbow]

What is a Fast Heading?

The EV1 heading sensor, @ 10hz is sometimes referred to as being "fast", as opposed to older 1hz fluxgate compasses.,

 

[PaulRainbow]

Thank you. I've changed it to a jpg. Should be visible now.

Some of the devices on the backbone are incorrectly labelled, although that doesn't affect usability. You also don't actually have an NMEA 2000 backbone, it's STNG.

I assume that you have terminated the left most 5 way port and the ITC5 ?

Also, do you have Seatalk power turned off on the ACU200 ? (you must turn it off if you are powering the network from elsewhere, as your schematic suggests.

I also assume that the Garmin plotter, the AIS and the VHF are connected using STNG to N2K converter cables ? A better way might have been to have connected the i60 in place of the Garmin plotter, then removed one STNG terminator, replacing it with a STNG to N2K backbone converter cable, adding a 4 way N2K port (terminated), then you could use standard N2K cables. Not really worth changing it now though.

The GPS17 is redundant and is best removed, if not done already. Looks like you have an Emtrak AIS, turn the GPS output off on that, as the plotter has built in GPS, best to have only one data source for GPS.

Nothing else jumps off of the page, so if none of the above helps, try unplugging as much as you can to see if you can isolate what's causing the issue. Failing that, you could try connecting the plotter to the Actisense 0183 converter, the plotter has one IN and one OUT port.