Design And Implementation Of Life Detecting System For Nuclear Magnetic Resonance Scanner

MRI scanner includes magnet subsystem, gradient subsystems, RF subsystem, and bed subsystem. The bed subsystem is responsible for carrying patients, and its life will affect the life of the instrument, while its speed decides the comfort and safety of detection.Considering its importance, the thesis choose the bed to be subject, and design the dectection system for the bed. The system can dectect the bed in lateral movement mode, vertical movement mode, and complex movement mode; display the velocity and position of bed by diplay part; and automatically alarm in case of errors.The hardware circuit of the system includes the main control part, motor control part, display part, communication part and key part. Main control part includes:core-component which is combined with AVR and CPLD, and voltage conversion circuit etc. Motor control part includes DC servo motor drive circuit, step motor drive circuit as well as relevant external auxiliary circuits.The software design of the system includes two parts:the MCU part and the CPLD part. The AVR MCU part is designed in ICC language. To enhance the readability and facility of transplant, choose modularize design. The main modules include:the main program, buttons scanning, display, motion control, and printing test reports. Choose QuartusⅡto design CPLD, using schematic way to realize count step motor pulse function, and then calculate the horizontal displacement and velocity.