Cerbo-S GX Manual

This chapter describes which data of the supported devices are available and the corresponding DGNs (Data Group Numbers).

RV-C defines several messages. A detailed specification of the protocol and message definition is publicly available on RV-C.com.

Generic

All virtual devices support the following generic DGNs:

VE.Bus Inverter/charger – com.victronenergy.vebus

Only VE.Bus MultiPlus/Quattro. Phoenix Inverter VE.Bus is also exported by this service, but then with number of AC inputs set to 0.

Status

Commands

Inverter – com.victronenergy.inverter

Phoenix inverter VE.Direct and Inverter RS.

Status

AC charger – com.victronenergy.charger

Skylla-I, Skylla-IP44/IP65, Phoenix Smart IP43 Charger.

Note: Instance fixed to 2.

Status

Commands

Solar charger – com.victronenergy.solarcharger

BlueSolar, SmartSolar, MPPT RS.

Note: Instance fixed to 1.

Status

Battery/BMS – com.victronenergy.battery

BMV, SmartShunt, Lynx Shunt, Lynx Ion, Lynx Smart BMS, BMS-Can batteries.

Note: Main (house battery): Instance 1, priority 119

Note: Starter: Instance 2, priority 20

Status

Tanks – com.victronenergy.tank

Tank level senders connected to the tank level input of a GX device, GX Tank 140, NMEA 2000 or VE.Can.

The tank instance is a combination of fluid type and occurence, where first, second, third, etc. corresponds to 0-15, 16-31, 32-47, respectively. So 3 is the first LPG tank and 16 is the second Fuel tank. We only use the first instance, i.e. tank instances 0-15.

Status

RV-C supports only 4 tank types (0..3), while Victron supports up to 11 tank types. The table with the additional tank types is Victron specific and is compatible with the tank types we use.

Supported tank types:

Note that Vendor defined means that these types are not defined in RV-C, but only used for Victron RV-C devices.

The GX device will assign an individual Unique Identity Number to each virtual device. Change it only when using multiple GX devices in one RV-C network.

The Unique Identity Number is used for the GX internal CAN-bus device "database" to compare devices during address determination. The Unique Identity Number can be changed in increments of 500, starting at 500. Example: The first GX device is automatically assigned the Unique Identity Number 1. For a second GX device, the unique identity number must be set to 501 (1 + 500).

Tanks

For compatible devices see chapter Supported devices.

Batteries

For compatible devices see chapter Supported devices.

This section provides a basic overview of how each device class will participate in the RV-C specification. In any case, "Level 1" integration is largely supported (basic operation), with case-by-case enhancements.

AC standalone Chargers

AC standalone Inverters

AC Charger / Inverter

Solar Controllers

SOC Meters

BMS (Victron, or Victron 3rd party supported)

Tank Level meters

RV-C utilises Instances in several ways:

Each usage of the Instance has a specific meaning, and a given device may at times utilise one or more of these instances.

DC Source Instance

In RV-C, a DC source is something that can generate and (optionally) store energy. Typically a battery but can also be a fuel cell or the output side of a DC contactor/disconnector.

A DC source can be thought of as a battery system and its associated physical bus, for example, the house battery, the DC bus bar and DC wiring. DC Source Instances are used to associate subsequent devices (e.g. a charger or an inverter) to the ‘DC bus’ it is connected to.

In this way it is possible to map out how all devices are connected with regards to their DC bus via their DC Source Instance value (starter battery and its alternator, house battery and its chargers etc.).

Note that in some cases (e. g. a DC-DC Converter or a Contactor), a device may be associated with two different DC Source instances. For example, a DC-DC converter could be associated with the two different batteries to which it is connected, while a contactor could be associated with the battery to which it is connected; the DC bus on the load side of the contactor then has its own DC Source instance

Though Victron is able to support more than one battery (a house and starter battery), the primary focus is on one battery. The dbus-rvc module will present the ‘primary’ battery to RV-C as ‘DC Source Instance = 1’ (house battery) information.

If present, additional Victron sensing devices will be presented using DC Source Instances of 2. An example is the optional starter battery voltage sensing on SmartShunts.

AC Line

AC line is much simpler, in that RV-C assumes a limited AC system, typically defined as Line 1 or Line 2. Victron supports 3-phase systems, which is not included in the RV-C specification. All installations with 3-phase systems are not supported by the dbus-RVC module and AC-related RV-C messages are suppressed.

Device Instance

Device Instance is a way to separate different physical devices of the same type. Example: if an installation contains two AC chargers attached to the same battery, each would be assigned a separate Device Instance while both would share the same DC Source Instance. Each charger would also be associated with an AC line, which may or may not be the same. In this way the AC charger is fully described in how it is wired on the AC and DC side while being able to be uniquely identified through its Device Instance.

Devices Instances are relevant within a given class of devices. An AC charger can define Device Instances 1 and 2, and these are unrelated to Device Instances 1 and 2 of a DC motor controller.

RV-C fault reporting:

This simple mapping allows external user displays to indicate an alarm or fault condition in a given Victron device, at which time the user should utilise Victron diagnostic aids for additional insight.

A critical concept in RV-C is the application of Device Priorities.

When used, a given device's priority will impact if it is allowed to transmit DGNs (e.g. a BMS with a higher priority should transmit details of the battery's status, while a MPPT controller with a lower priority should back down).

Device Priority is also at times used to allow for the favouring of one node vs. another, for example, it may be more desirable to use shore power AC vs. the inverter.

In the implementation of dbus-rvc, the following priorities will be hard coded into transmitted messages: