TU812V1 3BSE013232R1 ABB

The memory of PLC includes two kinds of system memory and user memory.The system memory is used to store the PLC system program,and the user memory is used to store the PLC user program.Today’s PLCs generally use electrically erasable E2PROM memory as system memory and user memory.

I/O interface unit

The function of the input interface circuit of the PLC is to input the signals generated by buttons,travel switches or sensors into the CPU;the function of the output interface circuit of the PLC is to convert the signals output by the CPU to the signals that can drive the external actuators,so as to control the contact Switching on and off of electrical appliances such as coils.The input and output interface circuit of PLC generally adopts optical coupling isolation technology,which can effectively protect the internal circuit.

PLC的存储器包括系统存储器和用户存储器两种。系统存储器用于存放PLC的系统程序，用户存储器用于存放PLC的用户程序。现在的PLC一般均采用可电擦除的E2PROM存储器来作为系统存储器和用户存储器。

输入输出接口单元

PLC的输入接口电路的作用是将按钮、行程开关或传感器等产生的信号输入CPU；PLC的输出接口电路的作用是将CPU向外输出的信号转换成可以驱动外部执行元件的信号，以便控制接触器线圈等电器的通、断电。PLC的输入输出接口电路一般采用光耦合隔离技术，可以有效地保护内部电路。