毕业设计（论文)基于PLC的工业搅拌过程控制系统设计.doc

基于PLC的工业搅拌过程控制系统设计摘 要随着PLC等许多处理器的发展，自动控制模式的电动机的数量越来越多。传统的控制方式因技术手段落后、生产效率低等弊端已不能适应企业生产的需要。本文主要介绍采用西门子PLC实现对液体搅拌系统进行自动控制。基于PLC构成的用于两种液体自动混合、自动搅拌和自动放料系统的控制目标、硬件组成、软件设计及系统功能，能模拟显示液体搅拌系统的全部工作过程。系统硬件主要由S7-300可编程控制器、电磁阀、泵以及液位变送器等组成，编程软件采用采用西门子编程软件STEP7。系统通过液位变送器将采集到的现场液位高度传送给西门子PLC，并由PLC对现场数据逻辑处理后，发出相应的控制指令，完成系统的自动控制。最后，系统使用RS-232接口与上位机相连实现PLC与计算机的通讯。系统不仅自动化程度高，灵活性强, 还具有在线修改功能，可满足不同的生产工艺要求。关键字：PLC，液体搅拌系统，液位变送器，电磁阀 DESIGN OF INDUSTRIAL MIXING PROCESS CONTROL SYSTEM BASED ON PLC ABSTRACT With the development of PLC, there are more and more automatic control electromotor. The traditional way of controlling can not meet the needs of enterprise production for its in low efficiency and low productivity. This paper introduces the rational application of SIEMENS PLC in the automatic control system of liquid mixer. PLC-based liquid composition for the two auto-mixing, automatic mixing and automatic discharge system, control objectives, hardware components, software design and system capabilities of liquid mixing system simulation show that all the work process. The System hardware is mainly formed by the S7-300 programmable logic controller, electromagnetic valve, pump and liquid location sensor, programming software using Siemens STEP7. The System through the liquid location sensor collected level information to Siemens PLC and then the PLC deal with on-site data, and sending corresponding control command to complete the system of automatic control. At last system is realized the communication between PLC and the upper computer by using the connection of RS-232.This system not only has high automation level and great mobility but also can alter the parameter on line, it can use in kinds of liquid location control systems.Key words: PLC，liquid mixing system，liquid location sensor，electromagnetic valve目 录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc232320020 1. 绪论 1 HYPERLINK \l _Toc232320021 1.1 液体搅拌系统的简介 1 HYPERLINK \l _Toc232320022 1.2 液体搅拌系统组成 2 HYPERLIN