The Design Of Signal Control System Of Sand Table In Urban Rail Laboratory

Urban rail transit laboratory is a comprehensive laboratory for practice which is built by simulating urban rail transit site and using the simulation knowledge.The laboratory is made up of orbit traffic sand table, urban rail transit station, rail traffic management center.And rail sand table consists of simulated railway lines, simulated station and simulated equipment.In order to make the whole sand table be able to simulate the actual operation of rail transportation, it is necessary to control the simulated equipment on the sand table.The simulated equipment on the sand table includes the signal machine simulated by LED(light-emitting diode), the switch machine simulated by the push-pull solenoid and the departure indicator simulated by digital tube.The whole sand table could simulate the operating station of rail traffic only when the bright or out of simulated signal machine,normal or reverse of simulated switch machine and time display of simulated departure indicator can be controlled in real time.Urban rail transit laboratory sand table signal control system can effectively control the signal of simulated equipment.The control system consists of the main control module, control module for simulated equipment, control module for simulated equipment interface.SPI bus is used for signal transmission between the modules.In this paper,STM32 is chosen as the controller. Clock circuit for controller, USB-to-serial circuit and program download circuit, network communication circuit, power and cascade circuit, SPI bus circuit, detection and control circuit for simulated signal machine, detection and control circuit for simulated switch machine, control circuit for departure indicator are designed by using Protel DXP.Communication program, master control program, and control program for simulated equipment are written by C language.The upper control software on PC machine sends control commands to control system through the network communication. The control signal is transmitted through the SPI bus to the simulated equipment circuit after procession of the main controller STM32. After converted by the simulated equipment circuit,the control signal could realize control and collection of status signals for simulated signal machine,simulated switch machine and simulated departure indicator.In order to make the control system be convenient to be used in the laboratory cabinet,According to GB3047-1986,We designed a 4U insert box for PCB system board which is easy for the hardware to plug and wiring.Control system combined with insert box, can accurately control and collect the signal of each simulated equipment, making sand table simulation field operation Rail real situation. So that the sand table could simulate the real operating situation of rail transit site.Teachers and students do not have to go to the project site by themselves. General experiment and research of urban rail transit can be carried out in the laboratory.After debugging, the control system has good stability, strong scalability and rigorous normality...