The CMP 21 pyranometer is designed for measuring the irradiance (radiant flux, Watt/m²) on a plane surface, which results from the direct solar radiation and from the diffuse radiation incident from the hemisphere above.
 
As a high performance research grade pyranometer it is fully compliant with all ISO 9060:1990 Secondary Standard Instrument performance criteria (highest possible ISO pyranometer performance category).
 
The CMP 21 has the same detector as the CMP 11 and individually optimised temperature compensation. A standard thermistor sensor is fitted to monitor the housing temperature. Each instrument is supplied with its own temperature and directional (cosine response) test data. 
It is the choice for scientific use and in top level solar radiation monitoring networks such as the BSRN (Baseline Surface Radiation Network) of WMO.
 
A waterproof socket is fitted for the signature yellow signal cable, which is available in a range of lengths pre-wired to the waterproof plug. The integral bubble level is raised to the top of the housing and can be viewed without removing the redesigned snap-on sun shield, which also covers the connector. The screw-in drying cartridge is easy to remove and the replacement desiccant is supplied in convenient refill packets.
 
This Pyranometer does not require any power as it supplies a low voltage of 0-20mV in relation to the amount of incoming radiation. When a higher voltage level or a 4-20mA signal is required, the AMPBOX is the perfect solution.
 
PRODUCT SPECIFICATION:
 
Spectral range 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 error (up to 80 ° with 1000 W/m² beam) < 10 W/m²
Temperature dependence of sensitivity (-20 ºC to +50 ºC) < 1 %
Operating temperature range -40 °C to +80 °C
Maximum solar irradiance 4000 W/m²
Field of view 180 °