The design and implementation of Modbus/TCP communication on WinCE platform

Traditional Modbus/TCP server-side protocol includes in many inappropriate blocking I/O operations. These operations frequently lead to receiving thread blockage in the communication. To solve this problem, some improvements such as asynchronous non-blocking and multi-threading technology are done on the TCP network layer of Modbus/TCP, which are completed in S3C2440 server-side by Visual Studio 2005. Furthermore, TCP / IP communications between server terminal and multiple clients are tested. The results show that the ping response time and the data sending or receiving time is less than 1ms and 1s respectively. Finally, a new TCP packet format in the process of TCP network communications is customized to carry out the Modbus/TCP functions on the Windows CE.net platform, so that a new method is established to provide an efficient and real-time master-slave dialogue.