NMEA 2000¶
The at-a-glance view of what the regulator does on the boat network. Every table — every message, every instance number, what each one looks like on a chartplotter or a Victron GX, and what the regulator reads back off the bus — is on NMEA 2000 in Detail. The electrical design of the port is on the NMEA 2000 hardware page; the firmware behavior is in External Interfaces.
The port¶
| Connection | Standard NMEA 2000 port — drops onto the backbone like every other device |
| Bus | NMEA 2000, 250 kbps, powered from the backbone (1 LEN), galvanically isolated (2.5 kV) |
| Termination | Internal jumper for end-of-backbone installs; leave open on a normal T-drop |
| Bus presence | A proper NMEA 2000 node (address claim, heartbeat, product info) when transmit is on; a completely silent listener otherwise |
What it does on the bus¶
Three independent switches, and all three ship off: transmit, receive, and charge-limit follow. Until you turn one on, the regulator is a silent listener.
It transmits the alternator as its own DC source, the battery bank, charge stage, field drive percentage, and a dedicated alternator-temperature instance to set an alarm on — plus engine RPM and the standard engine warning bits, which ship off so they cannot collide with a real engine gateway. Every message is individually switchable and every instance number is user-settable.
Nothing is fabricated: a value with no live source transmits as NMEA "not available", and a failed temperature sensor silences its message entirely — which trips the "data lost" alarm every major MFD offers. A silently failed temperature sensor is how alternators cook; this closes that hole with the alarm infrastructure you already own.
It reads battery data from any instance you select, the navigation and environment data the sailing-performance and anchorage features run on, and GPS time. None of it moves the alternator field — it is display, records and performance maths.
It follows charge limits published by a Victron system on VE.Can or an RV-C battery master. A received limit can only lower the regulator's own targets, never raise them; a published charge-current limit of zero is obeyed as stop-charging; every local protection outranks anything on the bus; and until you enable it, limits are decoded and displayed without being acted on.
Message by message and instance by instance: NMEA 2000 in Detail.