R&D Of A Valve Terminal Based On Modbus TCP

In a conventional pneumatic system, there are always lots of single functional component that doesn't depend on others. So when only one component broke down, the whole system can't work again, and make the assemblage, debugging, management and maintenance of the system more difficulty for us. The Modbus TCP Valve Terminal is a kind of intelligent equipment, which can optimize the hardware interfaces of components in a pneumatic system and improve its functional reliability. In a word, the pneumatic technology is looking forward to the appearance of Valve Terminal.After contrast Modbus and other fieldbus in capability, and according to the function characteristic of Valve Terminals, a new Valve Terminal with good performance in usability, efficiency, and intelligence is expected to be developed that combine the fieldbus technology with the Valve Terminal technology.Because modularization design ideology is used during the structure design of the Valve Terminal, the researching time and operating costs are both reduced. During the manufacture of the control module, an embedded system IPC@CHIP SC12 microcontroller is used as the kernel component, so the Valve Terminal can deal with multi-task at one time, protect its storage, and decrease the wastage of energy. In particular, for the MAC and ENDEC function of SC12, make the Ethernet port's circuit simpler, and enhance the corresponding performance of Valve Terminal. Besides, several key techniques are introduced in the process of software design. At first, the application in C can be understand easily; secondly, socket programming technology ensures that the program is abbreviated and reliable; thirdly, the use of multithreading technology increases the pace of software, optimize the real-time capability of Valve terminal.After communicating with PC simulative master, the Modbus Valve Terminal finished its conformance testing and interoperation testing, and the results indicate that the device can execute the master's command correctly and rapidly. In conclusion, Modbus Valve Terminal combines fieldbus technology with Valve Terminal technology very well.