摘要
本文介绍了利用西门子通讯模块CP340实现对CDT规约的解析和处理的一种方法,从而实现西门子S7-300PLC和具有CDT规约的RTU的通讯。首先介绍了CDT循环式远动规约的特点,接着介绍了西门子通讯模块CP340的使用,最后完整的给出利用300PLC解析CDT规约的方法,实现三遥功能:遥信、遥测和遥控。
In this paper,a method of analyzing and processing CDT protocol based on the Siemens communication module CP340 has been introduced,and the communication between Siemens S7-300 PLC and RTU based on CDT protocol has been carried out. The paper first introduced the characters of Cycle Distance Transmission protocol,then the use of Siemens communication module CP340,finally a complete method was been given out which can analyze CDT protocol using 300 PLC,and it can realize three remote functions：telesignalling,telemetry and remote controlling.
