ELV-841

The Hagner Light Sensor ELV-841 consists of a V_λ-filtered and cosinecorrected detector and an amplifier with regulated current output characteristic. The case is watertight, fitted with a thermostatically controlled internal anti-condensation heater. The ELV-841 light sensor measures light or other radiation with very high accuracy. The regulated current output characteristic allows it to be connected to long lines, e.g. to a remote data logger or computer. The ELV-841 is intended for continuous, stationary use outdoors or under extremely wet conditions. (A simpler version is also available for indoor conditions.)

Typical applications for the ELV-841 include control of artificial lighting, operation of shades and recording of light quantities. The design of the sensor is determined by the application for which it is intended, e.g.: Control of street lighting in vehicle tunnels, underpasses etc. For this application, the sensor is filtered to provide the same spectral response as the human eye (CIE, V_λ curve, with cosine correction) and internal case heating. For meteorological measurement and recording, with correction either to V_λ or special filtration, with or without cosine correction, and with internal heating. Special filters can be supplied for such applications as infra-red, photosynthesis or narrow-band measurements. When used indoors, in factories and offices no internal heating is required. The combinations are endless. The ELV-841 can also be modified with an optical system for luminance measurement (ELV-841-L).