Abstract
In the design of a series of field visits, according to the reality of demand, coupled with the understanding of the programmable controller and analysis, a PLC (Programmable Controller, or PLC) to achieve automatic dosage system control. Described in detail the automatic dosage system design steps, focusing on software development and debugging done, completed the dosage hardware configuration and software design and of using Century star configuration software monitoring real-time system.
The design consists of four parts, the first part is a brief introduction of the previous dosage system, in conjunction with field inspection experience with the design done this brief analysis and ideas. The second part is according to of graduation design, in conjunction with own practical experience, to bring forward a reasonable design, and design steps further introduction. In addition to the allocation of resources as well as in reality, the principle of device was introduced. The third part of the dosage system software design for the detailed presentation, and programming software and dictates were introduced, some of the procedures were interpreted detailly. The fourth part state the simulation software of configuration briefly and describe simulation process in detail.There are dosage configuration screen, the image of the entire design, perfect and practical.
    Through the debugging and co-ordination among the hardware and software to meet the requirements of industrial design to achieve automatic control dosage.

Keyword:PLC;Century star configuration; automatic dosage system

1 绪论
随着科学技术的不断发展，各项事业也在飞速的前进。工业的发展尤为突出，因此对工业生产过程的控制也提出了更高的要求................................