Real-time Malfunction Diagnosis And Automatic Alarm For The Time Keeping System At NTSC

The Time Keeping System at the National Time Service Center (NTSC), the Chinese Academy of Science, is the key part for the national standard time and frequency dissemination, which generates and keeps the local standard time UTC(NTSC) with the accuracy of UTC(NTSC) and the real time malfunction diagnosis and automatic alarm for time keeping system is underway. Both the part of the research work is of importance for further improving the accuracy of UTC(NTSC) and the reliability of the time keeping system. In this thesis, the method for malfunction diagnosis and the way of automatic alarming are mainly described.The Time Keeping System can be divided into three subsystems: The main (clock, time transfer and time comparison system), the accessorial (environment monitoring and controlling system) and the power supply system.A quite lot of equipment needs to be inspected in main system, but malfunctions of which are not easy to be detected. In order to resolve the equipment-monitoring of main system, in this thesis, we have established a synergetic method to synthesize the followings: analytical model (time sequence model of atomic clock), expert system, malfunction tree, signal processing method, and so on. The synergetic method mainly includes: noise-separating method based on time sequence model of atomic clock and malfunction- separating and positioning method based on malfunction-tree.The detected objects, in accessorial system, can be systematically monitored via LAN (local area network) hi the upper computer before it is completely auto-reformed.A telephone-speech alarming mode based on CTI technology has been adopted in the main and hi the accessorial system; we have also planned to adopt the method, which is combined with intelligent and programmable telephone dial-up device, asalarming mode for the power supply system.We have realized the real-time and automatic malfunction-diagnosis and malfunction-alarm in the main, the accessorial and the power supply system via malfunction diagnostic research and the design of alarming system and surveillant software. Via a period testing, it has been verified that the diagnoses and alarms are on time, accurate and reliable, and it can accord with practical requests of the unmanned watch.