The CM4 High Temperature Pyranometer is a radiometer specially designed for measuring solar or artificial light irradiance under the most extreme temperature conditions. With an operating temperature range of -40 ºC to +150 ºC and measurement up to 4000 W/m² it is a unique product. All the radiometer components are specially selected for their ability to withstand these extremely high temperatures and irradiance. The CM4 is supplied with a 10 m high temperature signal cable fitted to the instrument. The CM4 High Temperature Pyranometer has internal first-order temperature compensation, but it is also supplied with a built in Pt-100 temperature sensor to provide additional information on the measurement conditions. Monitoring the temperature during operations allows easy data correction afterwards for improved measurement accuracy. CM4 is supplied with a calibration table that gives the instrument sensitivity for a number of measurement temperature ranges and the maximum error in the measured irradiance values within each range. The screw-in drying cartridge is easy to remove and the replacement desiccant is supplied in convenient refill packets.