Multifunctional indoor air quality transmitters for building automation systems

Siro is an indoor air quality transmitter with a modern design and new hardware, including sensors. The transmitter is available with several optional air quality sensors including temperature, relative humidity, CO2 concentration, VOC (Volatile Organic Compounds) and PM (Particule Matter). It offers easy installation and adjustment, several different model options and various output signals that are configurable separately for each measurement parameter. Siro utilizes the industry standard NDIR measurement principle with self-calibrating ABC logicTM for CO2 measurement.

Available in April 2021.


Technical details

CO₂: ±33 ppm + 3 % of reading (typical)
Relative humidity: ±2.4 % rH (typical at 20 °C, 30 % rH)
Temperature: ±0.5 °C (typical at 20 °C)
TVOC: ±15 % of reading (typical)
0…100 μg/m3: PM2.5: ±15 μg/m3; PM1.0, PM10: ±25 μg/m3
100…1000 μg/m3: PM2.5: ±15 %; PM1.0, PM10: ±25 %
(at 25 °C ±5 °C)
Measuring units: CO2: ppm
Relative humidity: % rH
Temperature: °C
VOC CO2eq: ppm
TVOC: ppm, μg/m3
PM1/2.5/10: μg/m3
Calibration (CO2): Automatic self-calibration, ABC LogicTM
Supply voltage: 24 VDC/VAC ±10 %
Output signal 1–4: 0…10 V / 2...10 V / 0...5 V
optional 4...40 mA
linear to selected measurement (CO2, VOC, PM, rH or Temp)
Operating temperature: 0...+50 °C
Protection standard: IP20




Product series

Indoor air quality transmitter

CO2 sensor

With CO2 sensor (option not available with PM sensor)
Without CO2 sensor

VOC sensor

With VOC sensor (option not available with PM sensor)
Without VOC sensor

PM sensor

With PM sensor (option not available with CO2 and VOC sensors)
Without PM sensor

Relative humidity sensor

With relative humidity sensor
Without relative humidity sensor (option not available with VOC sensor)

Temperature sensor

With temperature sensor
Without temperature sensor (option not available with VOC or rH sensor)


Voltage output
Voltage and current output


With display
Without display

Other Indoor air quality: