2x Cerbo GX / Touch devices on 1x network?

Q&A and troubleshooting
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Two Cerbo GX / GX Touch Displays

Hi, I have read multiple posts / threads on this but I remain confused.

Certain posts seem to indicate that having TWO Cerbo GX / GX Displays in a system is a definite ’NoNo’ but others seem to suggest that should one ensure that the device / data instances do not clash / are unique then this is definitely possible…

So, some background :

We have a 14m yacht in for refit.

Thé 12V ‘house’ system comprises 4x 280AHr, LiFePo4 (circa 14Kw) batteries (123BMS), multiple PV panels/MPPT controllers & an extensive Nmea2000 / N2K network.

The 240V system (cooking, hot water & sockets etc) is supplied by 2x Multi (12V, 3000/120) units configured in parallel running off the 12V ‘house’ system.

The Cerbo GX & Touch 70 interface with these (12V & 240V) systems, incl. the N2K network, functions perfectly. :+1:

The 96V ‘propulsion’ system (no diesel engine) comprises circa 62Kw, LiFePo4 batteries (EMUS BMS), a Netgain HYPER9 motor / controller & various chargers.

So… We’re hoping that the (relatively) new (Venus OS 3.6x) ‘Boat Page’ could offer a display solution for the propulsion system BUT are unsure as to whether this is possible and, if it is, how to achieve this. To be fair, the wiring is pretty straight forward and naturally no high voltage (above 12V nom) would be connected the Cerbo GX / Touch 70.

At first glance, this is simply two distinct onboard systems - 1x ‘house’ and 1x propulsion… BUT…

1: we would like to link the two, ‘house’ and ‘propulsion’, systems such that boat speed, boat position and 12V system data would be available to the propulsion system (no link would mean that we’d need to (somehow) duplicate this data for the propulsion system).

2: the propulsion system utilises the J1939 CANBus protocol - not the N2K protocol and, whilst they are very similar, they are not identical.

My questions :

1: Is it possible to change the Cerbo GX Device and / or Data Instances such that they do not clash / such that they are indeed unique (as the CANBus protocol demands) and can run on one connected bus ? If so, can someone point me to the web-page / link please ?

2: is there a list of PGNs (Tx & Rx) that the Venus 3.6x update supports for its Boat Page ? Where could I find them please ?

3: does the Cerbo GX (running Venus 3.6x) accept J1939 PGNs or would a J1939 / N2K Converter be required ? I believe YachtDevices are close to releasing such a device but I’d still like / need a list of N2K PGNs (both Tx & Rx) that the Cerbo GX accepts tho’ for the Boat page :wink:

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Yes, this is simple - it can be done on the Settings>VRM>VRM Device instances tab:

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There are J1939/NMEA2000 protocol translator devices available, I saw one for about $120. This should help get the data to the NMEA system, then 2 GX devices are not required.

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Hi Mike,

Great - thanks… I hadn’t noticed that :roll_eyes:

1: I’m still searching for a list of PGNs that the Cerbo GX transmits / Receives in relation to electric motors / the Touch Boat Page. Pointers (location / link etc) please ?

2: Having a 2nd Cerbo GX / Touch isn’t a bad thing for this project - in fact it’s a great thing in that it enables data to be displayed at both locations (downstairs at the chart table and upstairs @ the helm / steering position) In addition the 2nd Cerbo would (I guess) provide addition input/output channels ?

3: Having not heard to the contrary, I’m guessing that the Cerbo GX will not accept J1939 PGNs. À N2K / J1939 converter is definitely a possibility but first step here would be knowing precisely which PGNs the Cerbo GX ‘likes’…

4: Is there a way to add additional N2K PGN Tx/Rx capability to the Cerbo GX (Node Red / MQQT etc) ? Say, for a PGN not currently supported… If so can someone point me in that direction please ?

As you can probably see, we would love to stay ‘all-Victron’ but I simply don’t know if this is possible given that the motor / controller / charger components all use J1939 (all pretty standard, I’m sure but… still not N2K) hence all my questions trying to figure out a Cerbo GX / Touch solution. Apologies…

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  1. Sorry, Can’t Help much here. I have a couple of electric motor controllers- I attach the doc- you may find it useful or not. NMEA2k is a highly secretive document you generally have to pay for it, I haven’t found any copies floating around.
    EZkontrol CANBUS MCU to METER V1.1 20230727.pdf (232.7 KB)
  2. I think with one Cerbo you can have a second screen located elsewhere, data is certainly available on both 2k and ethernet.
    3)I’m guessing that the Cerbo GX will not accept J1939 PGNs No, it won’t. There are J1939 to NMEA2k translators available for engines though.
  3. Yes, I think there is, but I have not done anything on this. Another subscriber has done a battery aggregator software, this may hold clues as to how to do that. Venus OS’s backbone is the D-Bus system.
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Thanks, Mike…
I’ll keep plugging away. It may be that the newer version 3.7 GX software can also help. I’m going to plug our Kvaser into the J1939 bus and try to sniff the PGNs from the EMUS BMS, the TC chargers and the SME ACX144 Controller… That way I may be able to be more specific in relation to the specific J1939 PGNs that I’m trying to convert to N2K / need accepted by the display…
Thanks again.