摘要：随着工业自动化的步伐逐渐加快，流水线已经在各种制造业和企业中运用。流水线中的传送带要求在加工生产时流水线上的物料能可靠、迅速的停止在指定的加工位置，但是传统变速电机的传送带速度控制设备体型庞大、费用高并不适合现代工业生产的高速发展，针对以上问题及皮带传送时有多种速度变化的要求，设计了变频器和PLC两者组合对传送带进行多种速度控制的系统。通过对异步电动机的调速原理和调速方法及变频器和PLC特点，对RS-485通讯做了详细的分析，然后对硬件选择做相关介绍，进而对该系统的关键技术做了详细阐述，最后对PLC控制进行编程，实现了变频器和PLC对传送带多种速度的控制。本系统可以很容易的改变电动机的速度，具有精度高、稳定性好、可靠性高、灵活性好的特点。67918

毕业论文关键词：变频器，PLC，速度控制

Abstract：With the pace of industrial automation gradually accelerate, the pipeline has been used in various manufacturing and enterprises. In the pipeline conveyor belt requirements in processing production line material can reliably and quickly stop the specified machining position, but the traditional variable speed motor conveyor speed control equipment of large size, cost high and it is not suitable for the rapid development of modern industrial production, according to the above problems and the transmission belt when various speed change requirements design combining the frequency converter and PLC on the transmission with a variety of speed control system. Through the asynchronous motor control theory and control method and characteristics of the inverter and the PLC, the RS-485 communication do detailed analysis, then the hardware choices related to introduce, then describes the key technologies of the system, finally carries on the programming of PLC control, to achieve the frequency converter and PLC on the transmission with a variety of speed control. This system can easily change the speed of the motor, with the characteristics of high accuracy, good stability, high reliability and good flexibility.

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Keywords：frequency changer, PLC, speed control 

目   录

1  前言 4

2  变频器与PLC的概要 4

2.1  变频器的概述 4

2.2  PLC的概述 6

2.3  异步电动机调速 8

3  RS—485串行通讯 8

3.1  RS—485串行通讯的特点 8

3.2  RS—485串行接口标准 9

3.3  RS—485数据传输协议 10

4  系统的硬件开发 12

4.1  通信系统硬件组成 12

4.2  变频器的选择 13

4.3  变频器参数设置 14

4.4  PLC的选择 14

4.4.1  PLC的选择 14

4.4.2  I/O点数的分配 15

4.5  硬件之间的连接 16

5  系统的软件开发 16

5.1  速度控制软件的设计 16

5.2  RS-485通信软件的设计 17

6  系统的调试与实现