Pyrgeometer with Heater and 4-20 mA Transmitter

R02-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.

  • Suitable for day- and night observations
  • On-board heater. Heating prevents condensation of water on the pyrgeometer window which, when occurring, leads to very large measurement errors.
  • High sensitivity


IR02-TR Pyrgeometer with Heater
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 150°. 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 180°. 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.

IR02-TR Design
IR02-TR pyrgeometer employs a thermal sensor with black coating, a flat silicon window with solar blind filter and an anodised aluminium body. IR02-TR houses an on-board heater. Heating prevents condensation of water on the pyrgeometer window which, when occurring, leads to very large measurement errors. IR02-TR has a high sensitivity. With the transmitter a typical datalogger no longer contributes to the uncertainty of the measurement

Suggested Use

  • General meteorological observations
  • Climatological networks
  • Agricultural warning networks (frost)

Areas of Application

  • Meteorology / surface energy flux measurement



longwave radiation

Optional measurands

– sky temperature
– surface temperature

Spectral range

4.5 to 40 x 10⁻⁶ m

Field of view angle

150 °

Response time (95%)

18 s

Rated operating temperature range

-40 to +80 °C

Transmitted range

-300 to 100 W/m2

Temperature dependence

< ± 3 % (-10 to +40 °C)

Calibration traceability


Optional traceability

to blackbody (ITS-90)


12 VDC, 1.5 W

Temperature sensor


Standard cable length

5 m (see options)


• Longer cable, in multiples of 5 metres
• Blackbody calibration (ITS-90)
• Adapted transmitted range
• IR02 version without transmitter


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