Design Of Switch Machine Pressure Monitoring System Based On Power Line Carrier Communication

Power line carrier communication is a kind of communication which takes the existing power line as the media for data exchange. It can reduce the cost of the system by saving the expenses on setting up a special line. With the development of network communication technology, it has been wildly used in automatic control field.The rail switch and converse equipment are very important, but unfortunately it is a weak link in railway. The movement of the rail switch is driven by hydraulic switch machine, it has great effect on the railway transport efficiency and traffic safety. In order to avoid accidents, workers have to check the hydraulic switch machine constantly to make sure that if it is working well or not. The railway is electrify and high-speed now, so ministry of railways has proposed an even higher demand on examination and repair to ensure driving safety.To improve existing methods that measure hydraulic pressure of switch machine, in this paper we design a kind of switch machine monitoring system which based on power line carrier communication. It can implement online and real-time monitoring on railway hydraulic switch machine. The following aspects are discussed in detail.(1) Transmission characteristic of power line circuit channel is studied and the commonly used communication technologies are analyzed. The spread spectrum communication technology is adopted in the realization scheme of this system.(2) The hardware circuitry system of low voltage electric power line carrier communication is make up with PL3201 and filter apmlifier and others auxiliary periphery circuit. Considering the expansibility of hardware system, the framework of mainboard and sub-board is used in part of data centralize system.(3) The efficiency communication protocol is desinged according to the actual situation of the system, and the partition mechanism of data verification is used to settle the bit error problem in the process of communication. It greatly reduces the times of re-transmission and effectively enhances the communicating efficiency of system in worst environment.(4) The assembling and debugging have been done on the spot, the disadvantages of the system has been found farther, and relative improvement has been finished. Finally, the advice of next work is provided.