MFD12 Not Seeing N2K

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Anonymous

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We've been having this problem for close to 2 years now and were at our wits end. I don't want to call it intermittent, but sometimes the MFD will not recognize the N2K network. This will happen on startup, either it starts up and sees the network or it doesn't. Once the network is on or off, it is like that the entire day. I can't tell if it doesn't see the entire network or not.

The problem that makes itself known is no water temp reading from our DST200 on the N2K network. The only other N2K device is our autopilot which seems to function normally, however the MFD will not take the heading sensor data form the Garmin autopilot.

This year we added an Icom M506 N2K and that hasn't had an issue either as far as displaying speed, GPS, etc. It seems like the MFD will always output N2K PGNs but doesn't take any input.

In the last 2 winters we've replaced the DST200 and had the N2K network scanned which revealed a bad terminating resistor which we hoped was it, it wasn't. (Can't tell if the electronics guy was truthful about the resistor or not.)

Other observations include the N2K device list on the Garmin won't have the MFD listed, but will have all other N2K devices listed when the problem is occurring.

When the problem does occur, I go into installation wizard and in the global data source tab, none of the N2K sensors are listed in the drop downs, only the Furuno network sensors. I hit refresh and sometimes they come back and I set them, then save and exit, sometimes it works, sometimes not.

My knowledge has narrowed it down to a problem within the MFD itself as all other N2K network devices seem to function as normal regardless of what the MFD is doing. Unfortunately were mid-season and pulling the unit is a last resort for the end of the year.

We have purchased but not installed yet an MFD8. I was thinking of swapping the entire N2K network over to the MFD8 and seeing if the problem follows or goes away. Then I know if the MFD12 is to blame or not.

Yes the MFD12 has 2.11 software.

Please help Johnny!
 
Yes moving the network over to another MFD would be helpful in troubleshooting.
My experience says that you have a bad NMEA 2000 network architecture. NMEA 2000 can be the worst. Intermittent is exactly how they behave when something is wrong with the network. If you can draw up your network showing all the cable lengths and terminations; I would recommend opening a support case via our web site. (www.FurunoUSA.com - SUPPORT - Ask Furuno A Question). We can review your network and see if we can spot something. When you move the network over to the MFD8, try to use the exact drop cable and T so the equipment used will be the same.
 
To my knowledge and what the electronics guy who set the network up says, the network is set up properly and was scanned. Also would the entire network crash if the architecture was incorrect or just a single device on the network? I work with trucks and a J1939 network is very similar with a backbone and 120ohm resistors and I have rarely had an entire network fail, more often a single device on the network. I don't have cable lengths handy but the network setup is a simple one:

Res---T---=====================---T------T------T------T------T------T---Res
DST200 Y Pwr MFD12 Yam GHC10HeadingM506

The left leg is under the head and the right backbone is under the dash. None of the branches have anything other than an accessory on them. I can get cable lengths if needed but I will have to get down to the boat for that. All the T's are Maretron micro except for the one for the M506 which is a garmin T and Garmin cable. However Id like to swap that to Maretron to keep everything uniform. The accessories on the right backbone are the yellow power drop, mfd, Yamaha nmea2k bridge, garmin ghc10 controller, garmin heading sensor, and lastly the icom m506.
 
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