This article is a reference for connecting power and sensors to your Thiamis. For the steps to add a sensor in Environet, see Adding and Configuring Sensors.
Power
12V DC: Connect to the SDI-12 PWR Euroblock connector: V+ (positive) and GND (negative).
5V: Either of the two USB-C ports.
⚠️ Never connect power to the RS-485 connector.
The RS-485 Euroblock (GND, A−, B+) looks like the power connector, but connecting power to it can damage the Thiamis.
Communication ports
Port | Used for |
RS-232 (RS-232 MUX port) | Most serial sensors (DustTrak, SoundPro, RAE, QUESTemp, Manta2, E-BAM, ES-642, TROLL). Supports a splitter cable for multiple sensors. |
RS-485 | Lufft weather stations. Data only. Do not connect power. |
USB-C | USB sensors and adapters (IrDA readers for GM460 and GX-6000, TROLL USB adapter). Also 5V power. |
SDI-12 PWR | Power |
GPS / LTE | Connectors for optional external antennas. These are add-ons, usually used when the Thiamis is installed inside an enclosure. |
Com Port and Com Type
When you add a sensor in Environet, you choose two settings:
Com Port: the Thiamis port the sensor is plugged into, including the letter port if you use a splitter cable.
Com Type: how the sensor sends data.
If these don’t match the physical connection, the sensor won’t report.
Splitter cables and letter ports
An RS-232 3-to-1 splitter cable lets up to three serial sensors share the Thiamis RS-232 port. Each branch of the splitter is labeled with a letter: A, B, or C.
Note which sensor is connected to each letter. You’ll select the same letter as the Com Port in Environet.
QUESTemp must use Port A. It needs a signal only Port A provides and can’t use ports B or C. In multi-device setups, connect the QUESTemp first.
DustTrak: when it’s the only device connected with an adapter cable, configure it for Port A.
InSitu TROLL (RS-232 adapter): connect the TROLL Com adapter to Port A.
Sensor connection reference
Sensor | Connects to Thiamis via | Cable / adapter | Notes |
TSI DustTrak | RS-232 (direct or splitter) | USB-to-RS-232 adapter cable | Port A when it’s the only adapter-cable device |
TSI Quest SoundPro | RS-232 | Serial connector cable (TSI 053-729) |
|
TSI QUESTemp | RS-232 | Serial cable (TSI 054-715) | Must use Port A |
Honeywell RAE Systems | RS-232 | RS-232 splitter cable | Powered by RAE Travel Adapter |
Eureka Manta2 | RS-232 | Underwater cable |
|
Met One E-BAM | RS-232 | DIN connector cable |
|
Met One ES-642 | RS-232 | DIN connector cable |
|
InSitu TROLL Series | RS-232 or USB | RS-232 TROLL Com (PN 0056140) on Port A, or USB TROLL Com (PN 0052500) | TROLL Com powered by its own adapter |
Lufft WS Series | RS-485 | 8-pole connection cable |
|
TSI GM460 | USB | IrDA reader | Pair in Environet |
RKI GX-6000 | USB | IrDA reader | Pair in Environet |
For full setup steps, see each sensor’s guide in Sensor Setup Guides.