Garmin GMI 20 and SignalK to NMEA2000

[joshuajayg]

As I continue to fine tune my system I've come across an interesting issue.  If I turn on my GPSMap 7608, the GMI 20 happily shows GPS Position and SOG.  If I turn it off and use the SignalK to NMEA 2000 plugin, SOG and GPS Position are no longer available on the GMI 20.  I have several other PGNs getting successfully sent from my SignalK server to the GMI 20 so I don't have a network issue.  I have checked the data log and I can see the pertinent information getting sent over the NMEA2000 bus (I'm using a USB GPS dongle.)  Is there possibly a formatting issue with the data that Garmin doesn't like?  I see that both the SOG and coordinates have a lot of trailing digits at times.  

Garmin has a NMEA technical reference that spells out which PGNs are required for a certain data type.  I have confirmed I have the required PGNs selected and being sent over the NMEA network.  https://www8.garmin.com/manuals/webhelp/...D424D.html

Joshua

[joshuajayg]

A little more detail...
When I'm moving, SOG, COG Magnetic, GPS Position, and GPS time all display fine. When I slow down near or below 1 kt, the GMI says the GPS connection is lost and the values go blank. KIP continues to show values fine.

[Boatingbaileys]

This is an interesting one. I seem to remember in OpenCPN, you could tell it that the boat isn't moving under a certain kt limit so it assumed it was anchored, but I can't remember seeing that setting anywhere else.

Just to confirm, you have two sources for data for the SOG/COG/GPS positioning, your GPSMAap and a USB dongle?

SK Data browser and KIP both show the data but the GMI doesn't?

Have you set the source for your data in the N2K plugin, i.e the USB dongle, and have you also had a play with:

Resend (seconds)
Resend Duration (seconds)

[joshuajayg]

Correct, the Garmin GPSMap sends that data over NMEA2000 and the USB dongle also sends the data over NMEA2000 via the SK to NMEA2000 plugin.  The dongle is connected to SignalK through the SignalK connections tab. 

The SignalK data browser and KIP both show the data but the GMI doesn't show SOG, COG, position, or time when my boat slows down near or below 1 kt. 

I had tried to set the source in the plugin but didn't see a change so I left it clear.  I normally run with the GPSMap off so there are not two sources of position data on the bus. 

I have not fiddled with the Resend and Resend Duration values.  I can give that a shot. 

I started collecting the data showing up in SignalK but got busy sailing in a congested area then had to pack up and leave so I didn't get all the data.  Sadly I'm away from the boat for a couple months now and won't have any more data until I can get back there.

Here's the one screenshot I got of my GPS dongle.

[Boatingbaileys]

OK - so we've confirmed you only have one source of data, however, I would try the filtering that using Source Priorities Settings under Server > Data Connections in SK.

I would also try and play with the values in the plugin.

Lastly, do you have a paddle wheel for Speed Through Water?

[joshuajayg]

OK - so we've confirmed you only have one source of data, however, I would try the filtering that using Source Priorities Settings under Server > Data Connections in SK.

I would also try and play with the values in the plugin.

Lastly, do you have a paddle wheel for Speed Through Water?

Yes, I have a water speed transducer.  I'll play with some settings when I get back to the boat.

[Boatingbaileys]

Ok - Let us know how you get on.

[Peggy]

Hey I'm having a similar issue. Unable to get GPS data from SignalK to display on my GMI 20. Actually just made a post about it, then found yours. 

Following

[joshuajayg]

Hey I'm having a similar issue. Unable to get GPS data from SignalK to display on my GMI 20. Actually just made a post about it, then found yours. 

Following

I read your other post.  You said you are doing this on the bench so you haven't been able to get any GPS speed with your setup either.  That at least lends some credibility to my problem of it being a stationary issue.  I could not get time, position, or GPS speed while stationary but once I started moving, all these things showed up on the GMI 20.  I hope to be back at my boat in March for some engine maintenance and electrical work.

I also purchased four ESP32 displays that the Baileys made a recent video about (two round, two square.)  That will be fun to fiddle with.  I imagine they will be dedicated inside displays.

Joshua

[joshuajayg]

Update: I tried fiddling with the resend settings in the SignalK to NMEA2000 plugin as well as setting the source to the GPS USB dongle but none of it helped. I did purchase a NMEA 2000 GPS receiver though so I solved the problem... with money. It's a better receiver anyway so there we go. I still have the USB receiver as a backup if needed, it just won't show data on the GMI 20.