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Enabling better global research outcomes in soil, plant & environmental monitoring.

SK01-D2 Pyranometer

The SK01-D2 is a simple pyranometer for monitoring total solar global radiation on a plane surface.

The SK01-D2 pyranometer is an major upgrade of our popular SK01-D sensor. The body parts have been extensively revised to raise the weatherproof rating to IP67 (immersion proof), and the aluminium components are now hard anodised for increased durability. The SK01-D2 retains the convenient features of protective glass dome, bubble level, and in-built signal amplifier.

SK01-D2 Pyranometer Features

  • Hard anodised aluminium for corrosion resistance.
  • Glass dome to keep debris off the cosine corrected diffuser.
  • In-built signal amplifier to give a millivolt output for easy measurement.
  • Circular level and adjustable feet.
  • Sealed to IP67 and fully weatherproof.

Solar radiation at Earth’s surface is typically defined as total radiation across a wavelength range of 280 to 4000 nm (shortwave radiation). Total solar radiation, direct beam and diffuse, incident on a horizontal surface is defined as global shortwave radiation, or shortwave irradiance (incident radiant flux), and is expressed in Watts per square meter.

The SK01-D2 pyranometer is for measuring solar global radiation. It uses a silicon photodiode detector shielded by a cosine corrected diffuser and has a glass dome to keep debris off the diffuser. It is sealed and fully weatherproof. The detector signal is boosted by a low noise amplifier that is drift stabilised.


Select a site that has an unobstructed view of the sun from sunrise to sunset. Place the instrument on a flat horizontal platform and adjust the feet with a 7mm A.F. spanner until the circular level is centred. Secure the instrument to the platform with a 5mm holding screw in the centre of the base; the screw should be brass or stainless steel.

Power up the instrument by connecting the lead to the terminals of a 5.5-14.5V DC supply (a fresh 9V PP3 alkaline battery will power the instrument for up to 200 hours). red to +ve blue to -ve.

Measure the output signal by connecting the lead to a voltmeter, data-logger, chart recorder, or similar instrument. yellow (or white) to +ve clear (or green) to -ve.

Note: the instrument has a low current drain and a 50ms settling time; it is suitable for unattended installation with a battery operated data logger periodically powering it up.


The SK01-D2 is calibrated for use in unobstructed daylight. The calibration is by outdoors comparison to a reference pyranometer. It is recommended that the calibration be checked annually.

The output signal is factory set to 1mV/W.m -2 (so 1000W.m -2 of sunshine = 1 volt).

Photodiode detectors do not have a flat spectral response and are therefore not recommended for use in indirect or artificial light. In daylight the spectral selectivity can cause small deviations from ideal response: global irradiance will tend to be overestimated by up to 2% in bright cloud conditions, and underestimated by up to 6% in heavy overcast conditions. The cumulative solar energy error from spectral selectivity is small.

SK01-D2 Pyranometer

Response time (to 95%): 30ms
Non-stability (per year): < ±2%
Non-linearity: < 1%
Directional response (30°- 80° zenith): < 1 ms< ±30 W.m-2 (ISO9060 2nd class)
Spectral response (w.r.t clear sun), SK01-D2: -6% (heavy haze) to +4% (bright cloud)
Temperature response: < ±0.15% per °C
Tilt response: no tilt error

In-built signal amplifier to give a millivolt output for easy measurement.
Chopper stabilised (for zero amplifier drift), with overvoltage & polarity reversal protection.
SK01-D2 spectral response varies with wavelength so it is calibrated for solar spectral distribution and is not recommended for use in indirect or artificial lighting.
Sealed to IP66, with internal desiccant (non-toxic silica-gel).
User’s Instructions and Calibration Certificate included.

Viewing Angle 2 pi steradians
Spectral Range (nominal) SK01-D2: 300-1150nm SK01-DP2: 400-700nm
Irradiance SK01-D2: 0-2000 W.m-2 SK01-DP2: 0-3000 μmol.s-1.m-2
Sensitivity SK01-D2: 1mV/W.m-2 SK01-DP2: 0.5mV/μmol.s-1.m-2
Calibration Accuracy ± 3%
Operating Temperature -35°C to +60°C
Power Requirement 5.5V to 14.5VDC, 3mA
Sensor Type silicon photodiode
Lead 3m
Mounting central M5 hole; adjustable feet
Shipping Size & Weight; Net Weight 150 x 150 x 150mm, 0.5kg, 0.3kg
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