摘要：论述了利用PLC 的串口通信技术，实现上位机对溴化锂制冷机组的远程实时监控。文中还对OMRON公司的C200H型PLC的通信协议进行了分析，并介绍了基于VC++的上位机通信程序设计思想。
关键字：PLC，上位机，溴化锂制冷机组，串口通信

Abstract： This paper presents the realization of a successful remote supervisory on a BrLi chiller, by means of RS-232 between PLC and Computer. The communication agreement of the style C200H of OMRON was analysed, and the method of VC++ program design is also introduced.
Keywords：PLC, supervisory computer, BrLi chiller, serial communication