Digital First Class Pyranometer with Modbus Over TTL and 4-20 mA Output

SR15 digital pyranometer series is an all-digital range of solar radiation sensors applied in general high-accuracy observations. SR15 pyranometers comply with the “first class” specifications according to the ISO 9060:1990 standard and “spectrally flat class B” requirements in the 2018 revision. Version SR15-D2A2 offers Modbus over TTL, and 4-20 mA current loop output.

  • Best measurement accuracy in first class
  • Improved response time
  • On-board calibration history


Improved Measurement Accuracy

Calibration of SR15 pyranometer has been improved; our latest calibration method results in an uncertainty of the sensitivity of 1.8 %, compared to typical uncertainties of higher than 2.8 % for this pyranometer class. SR15’s response time is < 10 s, a significant improvement relative to earlier sensors and competitors.

Use as Sunshine Duration Sensor

WMO has approved the “pyranometric method” to calculate sunshine duration from pyranometer measurements in WMO-No. 8, Guide to Meteorological Instruments and Methods of Observation. This implies that SR15 may be used, in combination with appropriate software, to estimate sunshine duration. This is much more cost-effective than using a dedicated sunshine duration sensor. Ask for our application note.

Suggested Use

  • PV system performance monitoring
  • General solar resource monitoring
  • Indoor simulated solar testing
  • Meteorological networks

Areas of Application

  • Meteorology / surface energy flux measurement
  • Solar energy / PV system performance monitoring


  • AMF03 mounting fixture
  • SHR02 shadow ring
  • PMF01 mounting fixture
  • PMF02 mounting fixture
  • CMF01 mounting fixture



hemispherical solar radiation

ISO 9060:2018 classification

Spectrally flat Class B (first class)

IEC 61724-1:2017 compliance

Class C


National Meteorological NetworksPV monitoring commercial and utility scalePV monitoring small sized meteorology / climatology, other




4-20 mA current loopModbus TTL

Calibration uncertainty

< 1.8 % (k = 2)

Calibration traceability

to WRR

Spectral range

285 to 3000 x 10⁻⁹ m

Response time

< 10 s

Zero offset a

5 W/m² unventilated

Rated operating temperature range

-40 to +80 °C

Temperature response

< ± 2 % (-10 to +40 °C)

Standard cable length

5 m


optional spring-loaded levelling, with or without tube mount

Communication protocol

Modbus over TTL

Transmission mode


On-board heater

Not included

Analogue output

4-20 mA current loop

Version order codes

SR15-D2A2, SR15-D2A2-LM01, SR15-D2A2-TLM01


• Spring-loaded levelling; practical for easy mounting, levelling and instrument exchange on flat surfaces (LM01)
• Tube levelling mount with set of bolts (TLM01)
• PMF01 bracket for tilted installations
• Longer cable; 10 and 20 metres length
• 20 metres extension cable with 2 connectors


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