Research On Switch Acquistion And General Track Signal Generator In Computer Monitoring System

This paper is about the railway signal monitoring system. The thesis can be divided into two parts, which are the switch signals acquisition and track signal generator, and spread research and design on them.At the beginning, the paper describes the history and recent situation of the computer monitoring system, and introduces switch signal sampling circuit. Then based on the switch acquisition with LPC2292 embedded microprocessor, the paper mainly introduces the software re-developing and debugging in the switch acquisition. The paper designs the hardware circuits and the codes of track signal generator.In the paper, the track signal generator uses LPC2138 chips as the processor, and extends LED display,key scan,filter circuits on the least system. Based on comparison of three methods and the frequency of generated signals, the paper chooses the best method to achieve track signal generator. The generator of Sine and CPFSK signals based on the theories of Fourier transform and low pass filter comes true. Then the paper researches and analyses the chosen methods. Finally by the method, that Sine PWM signal is filtered by RC to realize D/A conversion, the system generates 25Hz track signal; by the method, that PWM signal is filtered by low-pass to realize square/sine conversion, the system generates ZP-89,ZPW-2000A shift frequency signals. The generated signals can be tested by the monitoring system.In the paper, the software of switch monitoring module achieves the real-time monitor functions, and communicates with PC by CAN bus. After repeated tests at the spot, switch monitoring module as a part of the railway signal monitoring system has been successfully applied to some railway stations by Micro Union Co. Ltd...Finally, the paper concluded the major achievements of the research and puts forward the improvement.