说明：  本文介绍了在自由口通信模式下，用计算机读写S7-200 PLC存储区内相邻的多个字 节数据的通信程序设计方法，程序设计中采用了多种可靠性措施。
(In this paper, in a free port communication mode, using the computer to read and write S7-200 PLC storage area adjacent to a number of bytes of data communication program design methods, procedures designed to use a variety of reliability measures.)