Rs-485 Bus-based Distributed Underwater Computer Light Control System

With the development of modern technology and city beautification, Intelligent Beam Underwater (IBU), a lantern device integrated with optics, mechatronics, electronics and computer science, is being brought forward. The paper studies the distributed control system of IBU just based on the situation that it has not been developed in China at present.This paper puts forward a solution of IBU, which is based on Distributed Control System theory, Mixed Signal Micro-controller MSP430F123 and RS-485 Bus. After summarizing the development history and situation of IBU, the paper briefly introduces MSP430F123's features and architecture, and then makes a detailed description of its programmable logic control, peripheral modules, ultralow-power consumption and development tools. According to IBU's control specialty, distributed control feature and characteristic of working underwater, the whole system is divided into host management module and real-time control subsystem module. Based on the solution, the paper develops the hardware and software architecture and control method.The hardware and software architecture of the single subsystem is studied based on MSP430F123 and RS-485 Bus. The hardware system is divided into one main module based on MSP430F123 and four peripheral modules which includes power management, 485 transceiver, step motor driver and I/O control module. The software presents two control methods: Network commands control based RS-485 and Internal commands control. The software system is divided into modules including background control, external network and internal commands control and driver. In the background control module, the software mainly completes the initialization of whole system and switches between external network control and internal commands control. In the external network and internal commands control module, RS-485 network is analyzed according to OSI model. Additionally, the paper presents a dual direction data transmission fashion. In the study of Internal commands control, a method of storing data table in a FLASH memory is presented, which effectively solves the problem of large quantities of data.The whole control algorithm is studied and divided into three parts including pulse-generation,step motor control and position control. Regular interval's shift pulse-generating method is presented which can effectively eliminate "interval" in pulse sequence. According to control demand of color disc and shutter, control method and algorithm on position, direction and frequency is presented.At the end of the paper, a practical application of IBU is presented, which effectively confirms that the control system has good features and is apt to realize distributed control.