Limited Availability ›
This product has limited availability. It will be replaced by: SR30-L. Some accessories, replacement parts, or services may still be available when it is no longer available.
SR20-D2-L Digital Class A Pyranometer


The SR20-D2, manufactured by Hukseflux Thermal Sensors, is an ISO 9060:2018 spectrally flat Class A (secondary standard) digital pyranometer that measures solar short-wave radiation in a full hemisphere of the sky. It connects directly to a Campbell Scientific data logger and is designed for Modbus RTU applications that require high measurement accuracy in demanding applications such as scientific meteorological observation networks and utility scale solar-energy-power production sites.

Benefits and Features

  • Low temperature dependence
  • Onboard digital temperature sensor
  • Ultra robust connector, desiccant holder, and sun screen
  • Temperature dependence characterized and supplied for each instrument
  • Directional response tested on each instrument
  • Digital output (Modbus RTU)


Pyranometer with detached cable


Sensor HIgh-quality blackened thermopile protected by two glass domes
Measurement Description Monitors solar radiation for the full solar spectrum range
ISO Classification Spectrally flat Class A (secondary standard) pyranometer (ISO 9060:2018 )
WMO Performance Level High-quality pyranometer
Response Time 4.5 s
Zero Offset A 5 W/m2 (unventilated), 2.5 W/m2 (ventilated)
(response to 200 W/m2 net thermal radiation)
Zero Offset B ≤ ± 2 W/m2 (response to 5 K/h change in ambient temperature)
Non-Stability ≤ ± 0.5% change per year
Non-Linearity ≤ ± 0.2% (100 to 1000 W/m2)
Directional Response < ± 10 W/m2
Spectral Selectivity < ± 3% (0.35 to 1.5 x 10-6 m)
Temperature Response < ± 0.4% (-30° to +50°C)
Tilt Response < ± 0.2% (0 to 90° at 1000 W/m2)
Heater No heater available
Steady-state Zero Offset
  • < ± 0.5 W/m2 (at +20°C)
  • < ± 0.8 W/m2 (-40° to +80°C)
Calibration Uncertainty < 1.2% (k=2)
Level Accuracy < 0.1° (bubble entirely in ring)
Operating Temperature Range -40° to +80°C
Field of View (FOV) 180°
Measurement Range -400 to 4000 W/m2
Spectral Range 285 to 3000 x 10-9 m (20% transmission points)
Sensitivity Digital output
Output Definition Running average over 4 measurements (refreshed every 0.1 s)


Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.

Mounting Equipment

Product Compatible Note

Additional Compatibility Information

Compatible with all data loggers that support Modbus.

Listed Under

Common Accessory for the following products: