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Multifunctional indoor air quality transmitters


Technical Specifications


Siro is an indoor air quality transmitter with a modern design. The transmitter is available with several optional air quality sensors. The modular device can be equipped with CO2 concentration and VOC (Volatile Organic Compounds) measurements or alternatively PM (Particulate Matter) measurement, and in addition, temperature and humidity measurements. It offers easy installation and adjustment, several different model options and various output signals that are configurable separately for each measurement parameter.


The Siro series devices are available with a user interface that includes an LCD
display and buttons making the configuration of the device quick and easy. An external configuration tool is available for devices without the user interface. Siro utilizes the industry standard NDIR measurement principle with self-calibrating ABC logicTM for CO2 measurement.


Measuring elements:

Measuring units:

Calibration (CO2)

Supply voltage:

Output signal 1–4:

Operating temperature:

Protection standard:

CO₂: ±33 ppm + 3 % of reading (typical),
additional ±60 ppm for first weeks
Relative humidity: ±2.4 % rH (typical at 20 °C, 30 % rH)
Temperature: ±0.5 °C (typical at 20 °C)
VOC*: ±15 % of reading (typical)
*VOC sensor is tuned for typical IAQ Mix of 22 VOCs as defined by Mølhave et al. (1997)
0…100 μg/m3:
PM2.5: ±15 μg/m3 (at 25 °C ±5 °C)
PM1/PM10*: ±15 μg/m3 (at 25 °C ±5 °C)
100…1000 μg/m3:
PM2.5: ±15 % (at 25 °C ±5 °C)
PM1/PM10*: ±15 % (at 25 °C ±5 °C)
*PM1 and PM10 values are calculated from PM2.5 measurement reading with the default particle distribution.

CO2: Non-dispersive infrared (NDIR)
VOC: Complementary Metal Oxide
Semiconductor (CMOS)
PM: Laser-based light scattering particle sensing
Temperature: Integrated to CMOS
Relative humidity: Thermoset polymer capacitive sensing element

CO2: ppm
Relative humidity: % rH
Temperature: °C
VOC CO2eq: ppm
TVOC: ppm, μg/m3
PM1/2.5/10: μg/m3

:Automatic self-calibration, ABC LogicTM

24 VDC/VAC ±10 %

0...10 V (optional 2...10 V / 0...5 V, display or configuration tool required)

Optional 4...20 mA
Linear to selected measurement (CO2, VOC, PM, rH or Temp)

0...50 °C


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