20.1.6. Instance Translation
RV-C utilises Instances in several ways:
• DC Source Instance
• AC Line
• Device Instance (context dependent)
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.
With the exception of tank monitoring, Device Instances are hard coded as 1 for each specific device class
unless specified otherwise in the PGN table. Because the AC charger has a hardcoded instance of 2, to allow
coexistance with a inverter/charger with charger instance 1.
20.1.7. RV-C Fault and Error Handling
RV-C fault reporting:
• Fault conditions are reported using the DM_RV (0x1FECA) and J1939 DM01 (0x1FECA) DGNs.
• In release 1 the operational status bits, the yellow and the red light field are supported because they are stored in DSA.
• SPN is set to 0xFFFFFF during normal conditions, and 0x0 at any time a warning or fault condition exists in supported Victron
equipment.
• FMI is set of 0x1F (Failure mode not available) at all times.
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.
Color Control GX Manual
Page 123 Appendix
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