Commissioning

The gateway discovers the NMEA 2000 equipment on its own. Commissioning is therefore short: address the box, power its second bus, then check that what appeared matches the boat.

Everything below is run on the boat's Brain.

1. Wire it and check it lives

CAN 1 to the MUXEN bus, CAN 2 to the NMEA 2000 backbone, power on. The system LED must blink once a second. Anything else: see Common mistakes.

2. Find it on the bus

muxen-uds -i can0 uid --scan

A factory box has no instance number yet (InstanceNum = 255) and publishes nothing until it gets one. This scan finds it anyway.

Once the gateway is running, a UID scan answers several times with the same UID: once for the box itself, once for every NMEA 2000 device it has translated. They are all the same physical box.

3. Give the box its own identity

Only one device needs to be addressed by hand: the box itself, as a generic I/O device, function 17. Everything the gateway translates gets its instance number from the NMEA 2000 network.

muxen-uds -i can0 uid --uid <the-box-uid> --instance 4 --preferred-function-code 17

--preferred-function-code is not optional here: this box answers on many functions, and without it the tool does not know which one you are numbering.

Instance numbers run 0…62 and must be unique per function on the boat. Do this one box at a time — two unconfigured boxes on the bus at once collide on the parking address.

4. See what the gateway found

The gateway can list the NMEA 2000 devices it has recognised, with the MUXEN function and instance it gave each one:

muxen-uds -i can0 -F 17 -I <io-instance> routine --action 1 --routine 2

The answer is a count followed by one triplet per device: NMEA 2000 address, MUXEN function code, MUXEN instance — 63 meaning "seen, but not yet identified", normal for a few seconds after power-up.

Then watch them on the Brain:

mosquitto_sub -h 127.0.0.1 -t 'device/5/#'  -v   # batteries
mosquitto_sub -h 127.0.0.1 -t 'device/6/#'  -v   # inverters / chargers
mosquitto_sub -h 127.0.0.1 -t 'device/10/#' -v   # MPPT solar chargers
mosquitto_sub -h 127.0.0.1 -t 'device/27/#' -v   # alternator
mosquitto_sub -h 127.0.0.1 -t 'device/32/#' -v   # bow thruster

If the routine lists nothing at all, the problem is on CAN 2 — see Common mistakes — NMEA 2000 gateway.

5. Check the instance numbers

Each translated device took its number from the NMEA 2000 network. Decide whether that is the numbering the boat should use, because it is the numbering the screens will use. muxen-uds -i can0 scan shows the whole MUXEN bus: each function + instance pair must appear once, gateway devices included.

To renumber a translated device, write its InstanceNum:

muxen-uds -i can0 -F 6 -I 0 writeconfig --name InstanceNum --value 2

For Victron converters, MPPTs and battery monitors the gateway then asks the equipment to change its own NMEA 2000 instance to match, so the two stay aligned. For the alternator and the bow thruster it cannot: the MUXEN number changes, the NMEA 2000 number does not.

6. Tell each device which battery parc it belongs to

Every translated energy device carries a BindToParc parameter. Left at its default the gateway detects the parc from the first valid battery voltage it reads, writes the result, and never revisits it. Set it by hand when the automatic answer is wrong, or when the device has no battery voltage to work from:

muxen-uds -i can0 -F 10 -I 0 writeconfig --name BindToParc --value <parc>

7. Alternator and Cerbo GX: decide who drives the charge

If the installation has an Arco Zeus alternator or a Victron Cerbo GX, the gateway publishes the boat's battery figures and charge limits onto the NMEA 2000 network by default (N2K_EmitTarget = 1), and the equipment regulates on them. Set it to 0 to make the gateway read-only for that device. The alternator's current limiting also depends on three curves — see Reference — NMEA 2000 gateway.

8. Keep a copy

muxen-uds -i can0 -F 17 -I <io-instance> readconfig --save-as-csv nmea2000-gateway.csv

Read out each translated device too. A factory reset erases the instance numbers, the parc bindings and the alternator curves; the gateway rediscovers the equipment, but not the choices you made about it.