Design And Development Of The Control System Of RASA-5RP X-ray Diffractometer

Considering the capability, cost and other correlative factors, a new X-ray diffractometer control system is successfully developed for X-ray diffractometer alteration project of China University of Geosciences (Wuhan). The system is with a view to measure precision, rotational rate and veracity of diffraction data intensity.The main research of the dissertation is as follows:Firstly, the dissertation expatiates on the diffraction principium of X-ray and X-ray crystalloid and two collection methods of the crystal diffraction data. Based on aforementioned introduction, four units of the system that is X-ray, generate set, goniometer, radiation detector and computer control systems are analyzed. Introduce the analysis progress of crystalloid architecture and interrelated knowledge and discuss the function and design thoughts of X-ray diffractometer control system. All of these offer demand warrant for the design of X-ray diffractometer control system.Secondly, the design principle and control means of old X-ray diffractometer are researched. The design principle of computer software system are analyzed respectively from measure system software, the crystal architecture analyze software and drawing software of crystalloid architecture picture, by which the topology architecture of X-ray diffractometer control system is schemed out.Thirdly, the control objects of X-ray diffractometer control system include goniometer,semi-slit, X-shutter, ray attenuation, PHA and X-ray intensity data acquisition. The new system adopts multiple SCM distributed system control. That is to say, each SCM controls one or several modules that use RS-232 series port to connect the PC and complete the control and information exchange. The design implements each modules independent and noninterference, but can be controlled by computer and flexible combination that can satisfy requirement of measure system.Fourthly, the PHA and goniometer drivers are reserved in new system. By analyzing the advantages and disadvantages of all kinds of control modes of the step motor and synthetically considering equipment precision requirement, and then the principal and subordinate control of computer and SCM and optical encoder as the position feedback using the closed-loop control mode are chosen. Choose appropriate CPLD and SCM and implement the design of diffraction intensity data acquisition and feedback control modules.Fifthly, write the new drive program of step motor, device drive program, data acquisition and processing software and control function program on PC. Carry out the interface standardization by adopting the module design thought. And implement the menu selection interface instead of the old control program in EPROM memory key of console, which uses computer to actualize goniometer's control and diffraction data acquisition.Sixthly; keep notice on compatibility and transplant ability of different interface in control system and pay attention on measurability, expansibility and maintain ability of control system. he new system not only supplies the good software interface to data analysis software on PC, but also provides good hardware interface to hardware electro circuit, and offers test interfaces that is serial and JTAG interfaces during the debugging and testing phase, and offers enough hardware roomage and maintenance interfaces that is CPLD and JTAG interfaces to upgrade and maintenance.Finally, the dissertation introduces several ways to enhance the anti-jamming ability in the new system. All experience and lessons are summarized in developing and debugging the whole hardware and software and study out the primary improvements for the shortage of the system. The dissertation provides the reference to reconstruct and enhancing capability of other equipments.