Research On The Technology Of Photoelectric Digital Sunshine Recorder

Sunlight plays an important role in the growth of living things on earth. The incident radiation earth receives from the sun(sunlight) is the major energy source which promotes various physical processes and biological processes. Geographic location is a major factor which affects solar radiation intensity. Due to the influence of altitudes and orientations(aspect and gradient), different geographic locations have different areas exposed to sunlight and directions of sunlight, the solar radiation intensity therefore affected. In an era of grain shortage and energy shortage, sunshine duration monitoring plays an important role in guiding applications in various fields(e.g. agriculture, resource management, the construction of solar power plants, meteorology, civil engineering and ecological research).Most sunshine recorders used by meteorological departments currently are dark-tube sunshine recorders, which hold defects such as slow respond speed and low measuring accuracy. Based on the development of electro-optical detection, as well as the wide application of photoelectric sensor in electro-optical detection, this article introduces the research on the design of a photoelectric type sunshine recorder which adopted photodiode as the sensor. The article introduced in-depth research on principles of solar radiation measurement, installation structures of sensors, spectral response characteristics of photodiodes and photodiode amplifying circuit of photodiodes. It also illustrates the operating principle of the photoelectric sunshine recorder, the design of the hardwire circuit of every function module, the shell structure and the analysis of the measured data collected from the sunshine recorder prototype. This photoelectric sunshine recorder contains photoelectric conversion circuit, differential amplification circuit, filter circuit, A/D converter module, data memory module, clock module and communication module. The microprocessor adopted EP1C3T144C8 N high performance chips of cyclone series. And the outer shell structure adopted a symmetric design, which could well compensate the effect of scattered light on measuring results.The analysis of the measuring results of the calibrated photoelectric sunshine recorder shows that the device could meet the performance requirements of meteorological measurement. It also has advantages including high response speed, high measuring accuracy and strong anti-interference performance.