The CMP 21 is a high performance research grade pyranometer, and is fully compliant with all ISO 9060 Secondary Standard Instrument performance criteria (highest possible ISO pyranometer performance category).
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.
CMP 21 has the same detector as the previous CM 22 and individually optimized 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 drying cartridge is now a screw-in type that can be simply removed using a coin, for changing the desiccant that is supplied in convenient refill packets.
