The program method of serial communication between Mitsubishi A series PLC and host computer is introduced in this paper. The problems caused during th e program design have been discussed. The part of communication program with VB6 .0 is presented.

• 介绍了Mitsubishi的A系列PLC与上位计算机的串行通信程序设计方法；讨论了在程序设计中需要注意的问题；并给出部分采用VB6.；0实现的串行通信程序。