SMP 21 Secondary Standard Pyranometer

SMP21 Pyranometer with digital interface for meteorological networks, reference measurements in extreme climates, polar or arid.


  • Digital output – RS485 Modbus
  • High-level accuracy
  • ISO 9060 spectrally flat Class A pyranometer 
  • Individual temperature correction from -40°C to +80°C


SMP21 Pyranometer from Kipp and Zonen

The SMP21 pyranometer is a secondary standard pyranometer that combines the sensor technology from the CMP21 but an RS-485 Modbus interface along with analogue output. With internal desiccant and robust build quality, the SMP21 is very low maintenance.

The SMP21 has Modbus® RTU interface, amplified analogue output, improved response time and individual temperature corrected measurement data. The SMP21 is supplied with individual measured cosine response data. The wide and low power supply range from 5 to 30VDC makes integration in meteorological and solar energy stations easy. The SMP21 is protected against over voltage, reversed polarity and short circuiting.

SMP21 specifications

Spectral range (50% points) 285 to 2800 nm
Sensitivity 7 to 14 µV/W/m²
Response time 5 s
Zero offset A < 7 W/m²
Zero offset B < 2 W/m²
Directional response (up to 80° with 1000 W/m² beam) < 10 W/m²
Temperature dependence of sensitivity (-20 ºC to +50 ºC) < 1 %
Operational temperature range -40 °C to +80 °C
Maximum solar irradiance 4000 W/m²
Field of view 180 °