说明：  主要介绍三菱FX系列PLC与上位机之间的通讯协议，并采用CSerial类来实现串行通信，本文给出了程序设计方法和部分源代码
(Mitsubishi introduces the FX series PLC and PC communication between the agreement and the use of categories to achieve CSerial serial communication, this paper presents a programming method and some source code)