摘要
在巴基斯坦Fatima 2×60 MW蔗渣电站项目的调试工作中,遇到了各类Modbus通讯问题。在问题确认和调试实验的过程中,进行了大量的关于Modbus通讯的理论分析和实验研究。对于其中通讯延迟类问题进行分析后,得出经验和结论:基于TCP/IP协议的Modbus通讯,其通讯速率受通讯报文长度(报文字节数量)影响很小。而主要影响因素为:Modbus主站Query报文的发送间隔和报文循环发送周期、Modbus从站应答速度、主从站之间用于信息交互的报文数量。
Modbus communication problems has occurred in the debugging of Fatima 2×60MW Bagasse & Coal Power Plant Project in Pakistan. And in the process of problem confirmation and debugging experiments, we have done lots of analysis in theory and study with experiments. The following conclusion has been made after we analyzed the communication delay problems: the communication rate of Modbus communication based on TCP/IP protocol is rarely influenced by communication packet length(the quantity of byte), but mainly influenced by delivery interval and cycle of Query messages from Modbus Master to Modbus Slave, response speed of Modbus Slave, and the number of messages for information exchange between Modbus Master and Slave.
引文
[1] MODBUS Application Protocol Specification V1.1b3[E] April 26,2012, 2~4.
[2] Modicon Inc. Modbus Protocol Reference Guide[E]. EM-5650Rev.10 1999, 4~8.
[3]王达.深入理解计算机网Understanding Computer Networks[M].2013.