Research And Design On High Sensitive Discrimination Control System For Track Occupancy

Railway signal device is the basic equipment of railway transportation in which trackcircuit is the main method for vehicle supervision whether occupancy or not andtransmission electrical signal in railway management departments. Section occupancy state isnamed the shunting state of track circuit, is one of most basic and important parameters inrailway signaling control system, which is the main term of interlocking check in theinterlocking system, which directly affects the operation of trains, even would threaten thesafety train. If the status is not accurate, not only the transportation efficiency was obstructed,but also serious traffic accident even may be caused. Aiming at the low shunting sensitivity oftrack circuit in exist, a high sensitive discrimination control system which can detect thepresence or absence of a train on a railroad track was proposed, which also can adapt todifferent form track circuits. At the same time, electronic relay is cascaded in receivingterminal on the basis of the existing track circuit changed. Through hardware and softwaredesign, uses microcontroller discrete to collected signal, and drives the relay to motion inorder to realize opened or closed track circuit, depend on this technique, the reliability andavailability of track circuit is improved, and mades guarantee for railway transportation.There are two main models in the system, acquisition part and logic control part. Thewhole system is fitted with the outputs of lightning protection of outdoor track circuit, inwhich the acquisition part is used for the voltage sampling of track circuit as the input of thelogic control part, and microcontroller makes judgement of the voltage and actuates relay inthe end.Module idea is adopted in discrimination control system design. According to the systemrequirement analysis, the system is divided into six sub-modules, such as acquisition module,logic discrimination control module, communication module, power module, relay operationmodule and LCD module, and makes design from hardware and software. The core of thesystem is logic control part, in which uses mpu as the controller which type is STC12C5A60S2to complete the compare of input signals and ultimately control output. The collection moduleis used for data collection, including calibration voltage and real-time of track circuit.Finally, according to the requirement for environment spot, climate and safety of railwaytransportation, makes design for reliability and fail-safe of discrimination control system oftrack occupancy, and completes the run-time testing of hardware and software. In the light ofdebugging results, the system achieves all the functions, which could display the trainoccupancy state of the defective shunting section of track circuit real-timely and reliablywithout affecting the original track circuit. The shunting sensitivity of track circuit isimproved through system design.