New Artificial Climate Box Design And Implementation Based On LPC2478

As important plant stress factors, ozone concentration and ultraviolet radiation intensity have been widely used in research. However, as plant growth environment, temperature and humidity also have significant influence which cannot be ignored. At present in domestic and foreign markets, there is no such climate box with control systems of temperature, humidity, ozone concentration and ultraviolet radiation intensity measurement together in one chamber. Therefore, the development of this new artificial climate box will bring great convenience for experimental studys which can meet the need of repeatability and improve the accuracy of experimental conclusionsFirst of all, this paper introduced the current research status of artificial climate box and clear the subject content and key issues to be solved as well as the overall structure of article; the technical route was also determined. Based on above content, system demand analysis was carried out. According to overall objective and system function, the overall structure was built with the system working process, working principle and main technical indicator introduced.Secondly, in this article, we choose LPC2478 of 32 bit ARM7 series as microprocessor and choose appropriate sensor to measure environmental parameters. Then, data acquisition circuits were designed according to its characteristic. PWM and light coupling isolation integrated circuit drive the implementation of the components.In order to meet the real-time requirement,μC/OS-Ⅱwas transplanted to LPC2478, realizing multi-duties software design. In this part, four modules were divided, including the data acquisition module, PWM control module, communication module, and keystroke and data display module. We presented software realization scheme of the system based on the hardware structure design.Finally, through the comparison of the relative control algorithm, the traditional PID control was chosen to control single module according to the system characteristics and needs. However, the results show that strong coupling effect of mutual influence exists between the environmental factors and simple combination of the single modules can't satisfy the demand of control accuracy. By repeatedly debugging and combining the actuator characteristics, the traditional PID control was further improved to be more suitable for this system.By testing, The results show that the measurement and control system can achieve the desired function and effect.