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

The GX main RV-C interface and all virtual devices report the minimum required DGNs:

^* In addition to DGN DM_RV 0x1FECA, also J1939 DGN DM01 0x0FECA is announced for all RV-C out devices to support older RV-C control panels that do not support the DM_RV DGN.

Main interface

The GX main interface identifies as “Control Panel” (DSA=68) on RV-C and is responsible for requesting and processing data from all RV-C nodes.

DC Source messages

All DC connected devices are capable of reporting DC_SOURCE_STATUS_1. This includes the inverter/charger, inverter, charger, battery and solar charger services. VE.Bus Inverter/charger and Battery/BMS reports DC current and voltage, all other devices report voltage only.

According to the RV-C spec, only one node is allowed to broadcast DC source messages from the same instance. Every device type has its own priority which is used to determine which node must send the DC source messages. Consider the following system:

In this case the battery monitor broadcasts DC source data with instance 1, as this has the highest priority. Additionally the AC charger broadcasts DC source data with instance 2 and 3 (output 2 and 3), as there are no other devices with those instances. More information about DC source messages in the RV-C specification manual. Chapter 6.5.1 explains the priority mechanism.

VE.Bus Inverter/charger

Devices

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. The DSA is set to 66 (Inverter #1).

Instances

• Inverter: default instance 1, configurable from 1…13

• Charger: default instance 1, configurable from 1…13

• Line #1: default instance 0 (L1), configurable from 0…1

• Line #2: default instance 1 (L2), configurable from 0…1

• DC source: default instance 1, configurable from 1…250

Status

DGN	DGN#	Value
INVERTER_AC_STATUS_1	0x1FFD7	L1 AC out voltage, current, frequency L2 AC out voltage, current, frequency L2 data is not sent when not configured
INVERTER_STATUS	0x1FFD4	Inverter status
CHARGER_AC_STATUS_1	0x1FFCA	L1 AC input voltage, current, frequency L2 AC input voltage, current, frequency L2 data is not sent when not configured
CHARGER_AC_STATUS_2	0x1FFC9	Input current limit
CHARGER_STATUS	0x1FFC7	Charger state
CHARGER_STATUS_2	0x1FEA3	DC voltage, current
CHARGER_CONFIGURATION_STATUS	0x1FFC6	Maximum charge current
CHARGER_CONFIGURATION_STATUS_2	0x1FF96	Input current limit, Maximum charge current (%)
DC_SOURCE_STATUS_1	0x1FFFD	DC voltage, current Fixed priority of 100 (inverter/charger)

Commands

DGN	DGN#	Value
INVERTER_COMMAND 1)	0x1FFD3	Inverter enable/disable
CHARGER_COMMAND 1)	0x1FFC5	Charger enable/disable
CHARGER_CONFIGURATION_COMMAND	0x1FFC4	Maximum charge current  Note: this is a volatile setting and resets to the value the unit was configured with after a restart of the inverter/charger.
CHARGER_CONFIGURATION_COMMAND_2	0x1FF95	Charger input current limit

¹⁾ From RV-C you can control the charger and inverter part separately. These two on/off values are then combined into a single switch value (as seen on the VE.Bus page in the GX user interface, see top most item in below screenshot). If the inverter/charger is On, switching the charger off will result in Inverter only. Switching the inverter off will result in Charger only (when shore power is connected).

Victron defines the following options to control a combined inverter/charger:

State	Remarks
Off	Both, inverter and charger are switched off
Inverter only	Only the inverter is switched on
Charger only	Only the charger is switched on
On	Both, inverter and charger are switched on

This is reflected by the Switch menu option:

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. To avoid clashes on CAN-Bus you must set the second GX device to the unique identity range of 1000-1499. This can be done by setting the unique identity selector to 2 (2 * 500). This works exactly the same as for VE.Can, see the PGN 60928 NAME Unique Identity Numbers section.

Tanks

Tested with Garnet SeeLeveL II 709 and tanks from the RV-C out function of another GX device.

Batteries

Lithionics is the only supported RV-C battery (including DVCC support).

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: