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pmolettiere avatar image
pmolettiere asked

Is Cerbo GX N2K Certified?

I'm having a problem with marine instrumentation on my N2K network. The entire network is single manufacturer, and after looking at the network with a multimeter, the Cerbo GX does not seem to be conforming to specification. Specifically, when the N2K network is powered down (Cerbo is still connected to the LiFePo bank, and powered), there is no resistance between the two data lines on the N2K bus. When the Cerbo is removed from the bus, there is the appropriate 60Ω resistance. When the Cerbo is powered down too, ie., BMS is shut down, then the 60Ω resistance is present as well.

The other manufacturer wants to see N2K certification for the Cerbo — does anyone know if this has been passed?

Does anyone know if the N2K adapter cable is trying to power the N2K bus? There is a fuse hacked into the N2K end of the cable, but I'm unsure if the device is trying to draw power or provide it.

Any advice appreciated.


cerbo gxNMEA 2000 - N2K
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pmolettiere avatar image pmolettiere commented ·

FWIW, this link seems to imply that the Cerbo is not certified:

https://www.nmea.org/content/STANDARDS/nmea_2000_certified_products

This is the complete result for a search on Victron:

Victron Energy

De Paal 35
JG Almere Haven, 1351
Netherlands
www.victronenergy.com

Manufacturer Code : 358

BMV
Model #: BMV 1.0
Battery Monitor
Software Version: 1.0
Hardware Version: 1.0
Date Certified: 3/23/2012
Load Equivalency Number: 1
Lynx Shunt
Model #: Lynx Shunt 1.o
The Lynx Shunt is a precision battery monitor, with built-in shunt and main fuse. It is part of the Victron Energy Lynx system, providing easy installation and DC distribution.
Software Version: 1.01
Hardware Version: 1.0
Date Certified: 6/21/2012
Load Equivalency Number: 0
Skylla-i battery charger 24V/80A
Model #: Skylla 80
The Skylla-i is a is high-current battery charger. 24V and 80A.
Software Version: 1.15
Hardware Version: 1.0
Date Certified: 1/30/2013
Load Equivalency Number: 0
Skylla-i battery charger 24V/100A
Model #: Skylla 100
Skylla-i battery charger 24V/100A
Software Version: 1.15
Hardware Version: 1.0
Date Certified: 1/30/2013
Load Equivalency Number: 0
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pwfarnell answered ·

The Victron documentation states that the Cerbo GX will try to power the network via the VE CAN terminal.

"Also, the Victron VE.Can network will (in most cases) be powered with battery voltage. So for a 48V system, the voltage on the VE.Can network exceeds the NMEA-2000 accepted voltage levels.

Therefore, it is important to not connect those power cables.

The Victron cable used to connect both networks together, the VE.Can to NMEA 2000 cable, has a removable fuse which is to be removed in case separation is necessary. A printed warning label is attached to the cable to warn about this."

This is extracted from https://www.victronenergy.com/live/ve.can:nmea-2000:start which is referred to in the Cerbo GX manual https://www.victronenergy.com/media/pg/Cerbo_GX/en/marine-mfd-integration-by-nmea2000.html

Therefore, when you power down the N2K network, it will still be running from the Cerbo which is why you do not see the 60Ω resistance until you power down the Cerbo via the BMS. I suggest you try the system with the fuse removed.

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legacy avatar image legacy commented ·
When the NEMA backbone is powered down, the  impedance jumps up and down ...150 Ohms to zero and up again. When we disconnect the VE.Can-to-Nema 2000 cable. It is stable at 60 ohms. The  MFD manufacture believes this is causing problems on our network. In our case the Auto pilot abruptly disengaging.

Thoughts?




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