摘要:随着网络、计算机、数据库等相关技术的不断发展和完善，也极大地完善了自动化系统。根据配料生产的特点和要求，介绍了皮带秤S7-300 PLC自动配料控制系统的设计方案及仿真、使用方法。系统完成了配料系统的设计要求，并对控制系统的主要控制功能以及结构作了详细的介绍。而且着重说明了STEP7软件选用、安装、梯形图程序设计及整体系统的调试等情况。

　　　PLC的应用极大地提高了产品的质量和生产效率，在整个配料行业具有广阔的应用前景。配料系统在诸多行业的工业生产过程中占有极其重要的地位，配料工序的合理性、稳定性、准确性以及快速性直接影响到以后各生产环节的顺利进行。PLC的优点是外部接线简单，内部程序可变，在不改变接线的情况下，可以重新设计程，施工周期短，内部软继电器是寄存器，没有触点，故障率低，寿命长，抗干扰能力强，执行时间短，应用指令多，可实现复杂的控制功能等等。传统继电器的不足之处是有触点系统,故障率高，平均修复时间长，寿命短，功耗大，改变系统功能，将要重新接线，工作量大，容易出错，执行时间长等等。这就是采用PLC来进行控制的原因。同时，对PLC的结构、工作原理和分类都做了介绍。

关键词 皮带秤；s7-300；PLC；配料

Abstract:With the computers, networks, databases and other related technologies continue to develop and improve, the automation system consummate great. In this thesis, the ingredients produced in accordance with the characteristics and requirements, introduced the belt weigher S7-300 PLC automatic control system design and simulation.The thesis completed the system design requirements for ingredients, and control systems, as well as the main control structure in detail. And highlighted the STEP7 software selection, installation, ladder programming and debugging the whole system and so on.

　　　Application of PLC significantly improved product quality and production efficiency,Ingredients in the whole industry has broad application prospects. Batching system in many sectors of industrial production process of an extremely important position, the rationality of process ingredients, stability, accuracy and speed after a direct impact on the smooth progress of production.The advantages of PLC are simple external wiring, internal process variable, do not change the wiring in the circumstances, be included in the design process, a short work cycle, the internal relay is soft register, there is no contact, low failure rate, long life, anti-jamming ability, short execution time, application instructions and more can be achieved and so the complexity of control functions. traditional relay inadequacies have contact systems, the high failure rate, average repair time, a shorter life-span, power consumption, and change system will be re-wiring, heavy workload, prone to error, execution time and so on. This is the use of PLC for control reasons. At the same time,Of the PLC structure, working principle and classification are introduced.

Keywords  belt weigher  s7-300  PLC  ingredients