自动加料机plc控制系统（最终beta）.rar

自动加料机PLC控制系统（最终BETA）

摘要

针对传统的继电接触器控制的自动加料控制系统精度低、故障率高等缺点，本文提出了用PLC取代继电接触器对系统进行控制的方案。本文设计的以化肥袋装自动加料机控制系统为例，采用西门子公司的S7-200系列，主机为CPU226，模拟量输入模块选用的是EM231。在精度控制上，采用了秤体机械结构,设置一缓冲料斗将物料送往称斗,由称重传感器实现电子称量。控制器根据称重传感器的检测信号顺序控制缓冲料斗、称量斗、包装机构的动作,由可编程控制器通过软件对称重误差进行补偿,提高计量精度。采用二级给料方式,粗给料流量大,而细给料流量小。前者侧重于自动加料的速度,后者保证自动加料称量的精度,解决了加料效率与加料称量精度之间的矛盾。按照以上设计思路设计出了程序流程图和功能模块图，并设计出梯形图。为考虑系统的硬件的合理性及经济性，传感器和执行机构分别选择的是BK-2型S形测力/称重传感器和ZDLP型电子式电动单座、套筒调节阀。
实践证明，本控制系统具有精度高、成本低、抗干扰能力强、故障率低、操作维护简单等特点，具有良好的应用价值。
关键词： 可编程控制器；自动加料机控制系统；二级给料方式

ABSTRACT

According to automatic charging equipment control system of traditional relay contactor control with low accuracy and high failure rate, this paper has put forward PLC to substitute relay contactor control system. This paper takes the design of automatic charging equipment for fertilizer packaging as an example. This kind of control system adopts S7-200 product seriation made by Siemens—CPU226 host computer, EM231 for analog variable input module. In the control accuracy, it has employed the mechanical structure whose function like scales, installed a buffer bunker to transport materials, and then achieved electronic weighing by weighing transducer. The controller conducted by detection signal sequence of weighing transducer to control the motion of buffer hopper, weighing hopper and packing system, which uses software controlled by PLC to compensate weighing errors to improve measuring accuracy. Besides, the controller also adopts methods of secondary hopper feed, that is, if the controller gives more, the feeding flow rate will be lager or vise versa. The former focuses on the speed of automatic charging, while the latter tries to guarantee the precision of automatic weighing. So it has solved the problem between charging efficiency and charging weighing accuracy. In accordance with the above design thought, program flow chart, functional module and ladder diagram have been designed. With a view to the rationality and economical efficiency of hardware in the system, transducer and actuator are BK-2 in type, S force-measuring device/weighing transducer and ZDLP in type ZRSJP respectively.
It has been proved by practice that this control system has the characteristics of high accuracy, low cost, highly anti-jamming capability, and low failure rate, simply operating and maintaining and so on, together with good application value.
Key words: Programmable logic controller; Automatic charging equipment of PLC control system; Methods of secondary hopper feed

目录
0 前言 1
1概述 2
1.1课题总体分析与设计 2
2 可编程控制器 4
2.1 可编程控制器的基本结构 4
2.2 可编程控制器的工作原理 5
2.3 可编程控制器的性能 5
2.4 可编程控制器的应用 6
3  S7-200系列可编程控制器 7
3.1 S7-200 系列PLC的CPU 7
3.2 S7-200 系列PLC的通信 8
3.3  PLC应用中需要注意的问题 9
3.3.1 工作环境 9
3.3.2  控制系统中干扰及其来源 10
3.3.3  主要抗干扰措施 11
3.4 S7-200系列PLC模块 13
3.4.1 数字量扩展模块 13
3.4.2 模拟量扩展模块与热电阻、热电偶扩展模块 13
3.3 PLC与其他方案的比较 14
4 自动加料机PLC控制系统硬件设计 16
4.1 CPU选型 16
4.2  PLC输入输出点的地址分配表 16
4.3 PLC主机I/O接线图 17
4.4 模拟量输入模块的选用 17
4.4.1  模拟量输入模块概述 17
4.4.2 模拟量输入模块的选用原则 18
4.4.3 模拟量输入模块选型 18
4.4.4 模拟量输入模块与传感器接线图 20
4.5 执行机构的选择 20
4.5.1 电磁阀原理 20
4.5.2 电磁阀选用原则 21
4.5.3 电磁阀选型 22
4.5.4电磁阀与PLC的连接 22
4.6  测量机构的选用原则 23
4.6.1 传感器简介 23
4.6.2 传感器选择的基本原则 23
4.6.3 传感器的选型 24
4.6.4 传感器的选用小结 24
4.6.5 传感器信号放大电路 25
4.6.6 影响测量结果的因素及解决办法 26
5 自动加料机PLC控制系统软件设计 27
5.1系统流程图 27
5.2 控制程序设计 28
5.2.1 系统功能块图 28
5.2.2 控制程序设计 29
5.3 自动加料机系统控制程序图 31
5.4 提高系统动态称重精度的建议 37
6 技术经济分析 38
7结 论 39
致谢 40
参考文献 41
附录A  译文 42
附录B　外文文献 54