| Since the reform and opening-up, the land pollution, air pollution and other issues, especially the food safety, have been considered more and more serious along with the rapid development of economy. In order to solve the issue of vegetable safety, the establishment of soilless culture Vegetable-garden and the production of Green and Environmental products are being studied recently. They will not only improve the quality and quantity of vegetable, and reduce the cost of production, but also save the labor to improve the productivity.The development of the control system has experienced from the stage of “manual control” to “computer integrated control”. As a matter of fact, the traditional control method is hard to meet the environmental control requirement of plant growth due to the complex environment. However, with the progress of science and technology, the management and control of the Vegetable-garden is increasing gradually. At present, the intelligent control system of computer has been regarded as the mainstream of greenhouse environmental control system widely.The overall design of the hardware of this system is on the layered structure, which is composed of the control layer, the communication layer and the management layer. The Force Control has been used within the design of remote monitoring system to realize a remote monitoring and management of the Vegetable-garden; the Smart 700 IE touch screen has been used on the field and designed within the Win CC Flexible to achieve the parameter setting and functional control; The S7-200 PLC Siemens controller has been applied into the controlling machine and designed as well as developed under the system of STEP 7-Micro/WIN to achieve the detection and control of the environmental and nutritional liquid parameters. The GPRS has been used between the upper and lower computers to realize the remote wireless communication.The Siemens S7-200 series PLC controller has been considered as the core of the control layer to blend the nutrient solution and to regulate the environmental parameters in nowadays. Lettuce, as the example of nutrient solution blending, is controlled by fuzzy control technology on dimensions of acidity and conductivity to make the intelligent control successful. Actually, there are two ways of information collection, wired and wireless. The wired sensor is used to detect the p H and conductivity of nutrient solution. Zig Bee, the wireless temperature and humidity sensor is used to detect the environmental data. Besides, wireless technology has been applied into the layer of communication, meanwhile, GPRS DTU module has been used within the wireless data terminal to package PLC and then being transmitted through GPRS to the Internet. By this, the management transmitted intercourse data from device to monitoring system successfully. Terminally, data from GPRS DTU will be sent to the layer of management, and being processed here to realize the centralized monitor of the cultivation area. Functions of Management center monitoring system are complex, including remote monitoring, trend analysis, report output, data query and so on.The PLC control technology, fuzzy control technology, GPRS wireless communication technology and the remote intelligent monitoring of vegetable-garden has been applied into the thesis to realize the field control and remote control, including the automatic blending of nutrient solution, system-running monitor, switch on manual and automatic mode, automatic alarm and the remote wireless communicationThe system presented has been tested to insure a relatively high state of stability, safety and reliability, and it meets the design requirements appropriately. |
PDF Full Text Request