Victron energy Venus GX Manual page 72

GX ModbusTCP Manual
1. Introduction
ModbusTCP is a feature on our GX devices eg Color Control GX, and also the Venus GX.
ModbusTCP is an industry standard protocol, that can be used to interface PLCs or other third party
equipment with Victron products. Through the ModbusTCP interface you can read and write date to
the chargers, battery monitors, inverter/chargers and other products connected to the GX device.
Besides reading this GX ModbusTCP Manual, make sure to also read the ModbusTCP section in our
Data communication whitepaper.
By default, ModbusTCP is disabled. To enable it, go into the settings menu, scroll down to 'Services',
and then enable the ModbusTCP service.
2. Addressing, Unit-ID and Registers
2.1 Definitions
The ModbusTCP protocol has two fields for addressing. There is the Unit-id, also referred to as
Address, Station address or Slave-address in some PLC software. And the other field is the Register
address.
The Unit-ID is the device-selector: it tells the GX Device which connected device (ie. which
charger, inverter, or battery-monitor) you want to read, or write from. The GX Device then acts
as a ModbusTCP gateway.
The Register Address then determines the parameter to read or write: ie. voltage, or current,
and so forth.
2.2 Unit-IDs
To see a list of available devices, and their Address, go to Settings → Services → Modbus/TCP →
Available services:
GX ModbusTCP Manual