摘要
针对工控网络的结构特点,提出了一种具有透明传输和简单并联特征的专用调制解调器(MODEM)。其采用多进制频移键控(MFSK)的调制方法,在电话线路通频带内,无需数据压缩即可获得18.9kbps的平均传输速率。系统以80C196KBCPU为核心,数据端口采用三线制(TXD,RXD,GND)最简方式,无需控制信号事先建立载波,实现了主从式工控网络挂灯笼连接方式,可满足1.0km以上工控系统交换数据的需要。
According to the industrial control network, a kind of special MODEM is introduced to realized transparent transmission and direct parallel connection and a new method, MFSK,is ussed to modulate signals. Within the transmission band of telephone line, an average transmission rate of 18.9kbps can be achieved without data compaction. 80C196KB is CPU of the MODEM,the simplest mode, three-line(TXD,RXD,GND)mode is adopted on data port.So there is no need to set up carrier wave by the control signal before data sending. Thus all systems using the MODEM can be paralleled directly in the master-slave industrial control system.The MODEM can be used to exchange data in the control network with a range of 1.0km.
出处
《计算机测量与控制》
CSCD
2005年第6期567-568,共2页
Computer Measurement &Control
