Research On Distributed Control System Of High Temperature Vacuum Kettle

This thesis introduces a distributed control system of the high temperature vacuum kettle based on the RS-485 protocol to watch and control the growing complexion of the sapphire in the high temperature vacuum kettle.According to the computer control theory, the main task of this thesis is to design a distributed control system of the high temperature vacuum kettle. The system is a kind of principal and subordinate structure made up of one master part and six slave devices, principal RS-485 bus and the user-defined communication protocols to transmit data. We use a normal PC as the master part in this system and every slave device is a control part in which MSP430 single chip microcomputer is the core. The system can realize the real time supervision and control of the working of the high temperature vacuum kettle and the growing of crystalloid by reading some parameters, for example, voltage, current, power, weight, displacement and alert information, etc.The key part of this thesis is the software design, including interface design, serial communication and database design. The system has a friendly man-machine interface and a database, which is based on VB6.0.According to the user-defined communication protocols, it uses MSComm communication controller of VB6.0 to realize series communication between PC and microcontrollers. The software of PC can collect and dispose the data, and show the data on the operation interface. Besides, it can show the real-time data in the form of curve and the history data in the form of curvilinear chart. The system can save the technologic parameters and the temperature of refrigerant water in the database every 10 minutes. When a breakdown occurs, it can give an alarm and the software can save the data in database at the same time. In addition, it can visit the access database, add the database, delete the database, update and choose the database by data widget using the strong functions of VB6.0. The experimental operation results show that all the function indexes of the system can meet the design requirements and the system can work stably and reliably.