Advertisement
2020-11-10 02:37
7.4 NMEA2000-out technical details
7.4.1 Glossary
To make this text good to interpret, here is a glossary of used terms:
Virtual-device: a Battery Monitor, Inverter, or other Victron device that does not have a CAN-bus
port by itself, made available "virtually" on the CAN-bus by the NMEA2000-out function of the
GX Device.
CAN-bus: the VE.Can port on the GX Device, that, in the context of this chapter, is most likely
connected to a NMEA2000 network.
NMEA2000-out function: the software feature in the GX Device, which is described in this
chapter.
NMEA2000: Marine CAN-bus protocol, based on J1939.
Instance: there are many types of instances, and explained in detail below.
J1939: A set of standards defining a CAN-bus protocol, defined by the SAE organisation.
Address Claim procedure (ACL): a mechanism, specified by J1939 and used in NMEA2000, which
used by devices on the network to negotiate and assign each device on the network a unique
network addresses. Its is a number from 0 to 252. There are three special network addresses
defined:
1.
0xFD (253) - Reserved
2.
0xFE (254) - Unable to claim address - for example when all others are in use
3.
0xFF (255) - The broadcast address
7.4.2 Virtual-devices
When the NMEA2000-out feature is enabled, the GX Device acts as a bridge: it will make each Battery
monitor, Inverter/charger or other device that is connected, available individually on the CAN-bus.
Individually, as in each with its own network address, its own device instance, function codes, and so
forth.
For example, a GX Device with two BMVs connected on a VE.Direct port and an inverter/charger
connected using VE.Bus, will make the following data available on the CAN-bus:
Address Class
0xE1
130 (Display)
0x03
35 (Electrical generation) 170 (Battery) The 1st BMV
0xE4
35 (Electrical generation) 170 (Battery) The 2nd BMV
0xD3
35 (Electrical generation) 153
0xD6
35 (Electrical generation) 154
The used network addresses are random examples. Network addresses can change due to the
J1939/NMEA2000 Address Claim Procedure (ACL), and they are not and cannot be configured to a
permanent value. Even though they might seem fixed, when checking with a NMEA2000 monitoring
tool, adding or replacing devices from the system might lead to changes in the network addresses.
Victron Energy - https://www.victronenergy.com/live/
53/58
Function
Description
120 (Display) The GX Device itself
The inverter/charger (AC-output)
The inverter/charger (AC-input)
Color Control GX manual
Advertisement
