摘要
为了实现基于 PC/PCC (计算机/可编程计算机控制器) 的集散控制系统的多机实时通信, 提出了基于 RS- 232的多机通信总线。该总线设计了硬件逻辑电路, 系统中的各个终端通过此逻辑电路查询得知总线状态, 并在占用总线时通过该电路锁定总线以避免多机通信在 RS -232串行通信中遇到的数据冲突问题, 并以此为基础提出了合理的数据总线分配方法, 不仅保证了总线的合理分配使用,并且满足了系统各优先级不同的通信任务的实时性。PC/PCC总线式集散控制系统, 不仅硬件实现简单, 而且软件实现可靠, 较好地实现了系统中的多机实时通信, 同时解决了数据冲突问题。长时间通信测试结果表明该系统的多机通信运行可靠, 实时性好, 较好地满足了系统的要求。
This paper introduces a multi-terminal communication bus based on RS-232 to realize real-time communication in distributed control system. A hardware logic circuit is designed; so every terminal can get bus status by inquiring about the circuit, and engross the bus when it wants to get the bus. And a method of assignment of data bus is introduced. These not only meet the requirement of assignment of data bus, but also meet the requirement of real-time communication. This system, which is realized simply and reliably, gets good performance. At last, the results from a longtime test on this system have proved its reliability and the real-time communication among PC and PCC, PCC and PCC. So, it meets the requirement of the system.
出处
《现代电力》
2005年第1期76-80,共5页
Modern Electric Power
关键词
可编程计算机控制器
串行通信
数据帧
帧驱动器
通信协议
programmable computer controller
serial communication
data frame
frame driver
communication protocol
