【作者】 任广起；

【导师】 王琨琦；

【作者基本信息】 西安工业大学 ， 机械电子工程， 2012， 硕士

【摘要】 在摄影工程、医疗卫生、照明工程和交通安全工程等相关领域中,照度的测量及其应用是越来越普遍。对照度测量系统的要求不仅仅局限于精度,而且在功能方面也不断的要求多样化,智能化。本文设计了一种以单片机AT89C52为主控部件,具有自动量程转换、增益自动可调、测量精度高、成本低廉、不仅能够测量静态光源而且能够对动态光源的峰值照度进行测量的照度测量系统。根据动态光源和静态光源的照度特性间的差异,提出了一种动态增益调节法,并采用该方法与量程区间控制法相结合,实现对静态光源的照度测量和对动态光源发光峰值时的照度测量。本文的主要内容包括以下儿部分：(1)光电转换前置放大电路的设计：本设计选用硅光电池作为探测器,在光电转换过程中硅光电池输出的光电流很微弱,需要对微弱的电流进行前置放大。而选用的模数转换器输入端是电压信号,所以前置放大器应设计为电流电压(Ⅰ-Ⅴ)变换器的形式。(2)自动量程转换电路的设计：光照度在0.000lx-2000lx范围产生的光电流范围太大,照度范围被划分为四个区间,微处理器控制模拟开关CD4051实现不同照度区间之间的切换。(3)动静态光源照度测量方法设计：采用动态增益调节法与量程区间控制法相结合,实现对静态光源照度的测量和对动态光源在峰值发光强度时照度的测量。(4)键盘和显示电路的设计：设计采用矩阵键盘和数码管静态显示电路。(5)照度测量系统的软件设计：系统软件设计包括量程自动转换的软件设计,单片机与CS5531串口通信的软件设计,动静态光源照度测量的软件设计,键盘识别和数显的软件设计以及单片机与PC机进行通信的软件设计。通过对照度测量系统硬件电路的设计和软件的设计与调试,系统在测量范围为0.0001lx-2000lx,精度为满量程的1%这两方面基本上达到了设计要求,同时也实现了对静态光源照度的测量和动态光源发光强度峰值时照度的测量。更多还原

【Abstract】 The illumination measurement and application are more and more widespread in these related fields of photography project, medical and health, lighting project and traffic safety project. The requirements for illuminance measurement system are not limited to the accuracy, but also in terms of functionality which had been required the diversity and intelligent. An illuminance measurement system was designed in this paper. The master of the system is SCM AT89C52. The character of system is automatic range switching, automatic adjustable gain, high accuracy, and low-cost. At the same time, the system not only can measure the static light source but also measure the peak illumination on the dynamic light source.A new method on dynamic gain adjustment was proposed according to the difference illumination characteristics between the dynamic light and static light sources. By using this method on dynamic gain adjustment combined with the method of range interval control, the static light illumination measurement and the dynamic light sources illumination measurement when in the peak time were achieved. The main contents of the paper included following five sections:(1) The pre-amplifier circuit was designed on photoelectric conversion:the silicon photocell was used as a detector in the paper. The output photocurrent of the silicon-solar cell is very weak in the photoelectric conversion process. Therefore, the weak current must be pre-amplified, But the analog-to-digital converter need input voltage signal, the preamplifier should be designed to the form of the current-voltage converter. (2) The design of the automatic range converter circuit: Because of the generated photocurrent is too wide in the illumination range 0.0001lx-2000lx, so, the illumination range is divided into four intervals. The switch between different illumination intervals was achieved by the microprocessor controlling the analog switches CD4051. (3) The design of intensity measurement method on dynamic and static light sources:The static light illumination measurement and the dynamic light illumination measurement in the peak luminous intensity were completed by the method on dynamic gain adjustment combined with the range interval control. (4) The design of the keyboard and display circuit:The matrix keyboard and digital tube display circuit were designed in this paper. (5) The software design on illuminance measurement system:The software design on the system included the software design on automatic range switching, the software design on the serial communication between single chip computer and CS5531, the software design on static and dynamic light sources illumination measurement, the software design on keyboard identification, the software design on digital display and the communication between SCM and PC.Through designing the hardware circuit and debugging the software program on the illumination measurement system, the system basically met the design requirements in these two areas for the measuring range is 0.0001 lx-2000 lx and the accuracy is 1% of full scale, at the same time, the static light illumination measurement and dynamic light source intensity peak illumination measurement were completed.更多还原