Victron energy Color Control GX Manual page 12

Optional/additional external sensors are either connected to the solar irradiance sensor with pre-installed plugs or pre-wired to the
solar irradiance sensor (external module and ambient temperature only). When external sensors are connected via an
appropriate solar irradiance sensor, all measurement data is transmitted to the Victron GX device with the single interface cable.
Each model solar irradiance sensor within Si-RS485 series has a different capability with regards to external sensors (or comes
with an external sensor pre-wired), so carefully consider any future desires/requirements before initial purchase.
It is also possible to connect an independent
Ta-ext-RS485-MB ambient temperature sensor
irradiance sensor or in addition to one.
Operation
The IMT Si-RS485 series solar irradiance sensors operate using RS485 electrical interface and Modbus RTU communication
protocol.
The required interface software is pre-installed within the Venus OS, however the Victron GX device must be running recent
firmware - FW v2.40 is the minimum requirement.
Physical connection to the Victron GX device is via USB port and requires a Victron RS485 to USB interface cable.
A suitable external DC power source (12 to 28 VDC) is also required - the sensor is NOT powered via USB.
Wiring Connections
The schematic in the installation guide below depicts the wiring configuration in a typical installation.
Wire connections
Si-Sensor Victron RS485 to USB interface
Brown Orange
Orange Yellow
Red -
Black
Black (thick) -
- Red
Page 8
Color Control GX Manual
IMT Tm-RS485-MB module temperature sensor
(visible as 'external temperature') directly to the Victron GX device, without a solar
Signal
RS485 Data A +
RS485 Data B -
Power Pos - 12 to 28 VDC
Power Neg/Gnd - 0 VDC
Ground / Cable Shield / PE
Power Pos - 5 VDC (not used)
(visible as 'cell temperature') or
Installation
IMT