IR02-TR pyrgeometer

Pyrgeometer with heater and 4-20 mA transmitter

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IR02-TR is a pyrgeometer suitable for longwave irradiance measurement in meteorological applications. The instrument can be heated, which improves measurement accuracy as it prevents dew deposition on its window. IR02-TR houses a 4-20 mA transmitter for easy read-out by dataloggers commonly used in the industry.

IR02-TR measures the longwave or far-infra-red radiation received by a plane surface, in W/m2, from a field of view angle of approximately 150o. Longwave radiation is the part of radiation that is not emitted by the sun. The actual field of view angle of IR02-TR is not the ideal 180o. The reduction of this field of view makes it possible to offer an instrument at an attractive price level, while the accuracy loss is relatively small. IR02-TR has a window with a cut-on at 4.5 x 10-6 m, making it suitable for day- and night observations.

Using IR02-TR is easy. The pyrgeometer can be connected directly to commonly used data logging systems. The irradiance in W/m2 is calculated by using the transmitter’s output and the temperature reading. The final result is calculated taking into account the irradiance radiated by the sensor itself (Stefan-Boltzmann law). In IR02-TR’s standard configuration, the 4 to 20 mA output corresponds to a transmitted range of -300 to +100 W/m2. This range can be adjusted at the factory upon request.

Click on drawing in Gallery for IR02-TR dimensions: Standard cable length is 5 m. All dimensions are in mm.


Calibration of pyrgeometers used for downward longwave radiation is traceable to the World Infrared Standard Group (WISG). This calibration takes into account the spectral properties of downward longwave radiation. As an option, calibration can be made traceable to a blackbody and the International Temperature Scale of 1990 (ITS-90). This alternative calibration is appropriate for measurements of upward longwave radiation (with IR02 pyrgeometers facing down).

Suggested use

  • general meteorological observations
  • climatological networks
  • agricultural warning networks (frost)


  • longer cable, in multiples of 5 metres
  • blackbody calibration (ITS-90)
  • adapted transmitted range
  • IR02 version without transmitter

See also

  • alternative instrument: research grade pyrgeometer model IR20 for higher accuracy longwave radiation measurements
  • pyrgeometers are often used in combination with pyranometers for solar radiation (shortwave) measurement. View our pyranometer products


Similar products

IR02 pyrgeometer

Pyrgeometer with heater

IR20 & IR20WS pyrgeometer

Research grade pyrgeometers

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