注塑机控制系统是注塑机整机的一个重要组成部分，其性能优劣对整机至关重要。本论文首先确定了注塑机控制系统的设计方案及思路，经过与单片机控制、微机控制、继电接触器控制等控制系统相比较，决定采用PLC来实现对注塑机的控制。确定了PLC输入和输出接口的属性，将注塑机的所有检测开关、限位开关、手动操作开关和主令开关等进行确切的分类和编号，从而确定了I/O口的数量。根据输入输出的数量、类型确定PLC的型号为FX_2N-MR，完成了注塑机主电路和控制电路等硬件电路的设计。软件设计方面，根据注塑机各个动作制出注塑机的工艺流程图，根据此工艺流程图，设计出注塑机的动作流程图；根据动作流程图，写出注塑机的状态转移图，并依据状态转移图写出步进梯形图。

         关键词：注塑机; 可编程控制器; 控制系统; 状态转移图; 步进梯形图

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

            The control system of injection molding machine is an important part of the whole machine, the pros and cons of the performance of the machine is essential. In this thesis, I determine the design and ideas of the control system of the injection molding machine firstly. According to the comparison with the single-chip control, the computer control and the relay contractor control, PLC is chosen to control the action of the injection molding machine. When the properties of the PLC input and output interface is determined, I classify and number the detection switch, limit switch, manually operated switch and master switch of the injection molding machine in order to determine the number of I/O put. Based on the number and types of input and output, we could determine the model of the PLC is the FX_2N-MR. Then the design of the main circuit and the control circuit is completed. According to each action of the injection molding machine, the process flow diagram is worked out. Then the action flow diagram of the injection molding machine is completed according to the process flow diagram. At last, we could work out the state transition diagram according to the action flow diagram, and write down the stepladder in accordance with the state transition diagram.

           Keywords: Injection molding machine, Programmable logic controller,                 Control system, State transition diagram, stepladder