针对目前炼镁炉人工控制、操作易失误、不能连续监控和记录等现实问题，依据炼 镁生产工艺要求，研制了一种以PLC 为控制核心的生产计算机自动控制系统，运用DCS 工业控制设计理念，实现了系统的集散控制，完成了对运行状态的控制和记录。 论文论述了系统的总体设计、MODBUS 通信协议设计、各模拟量的采集、多路电磁阀门的控制方案、控制柜的接线设计，其中包括温控模块、真空机模块、PLC 可变程逻辑控制器的程序设计，生产计算机的上位机程序设计。 系统以PLC 作为控制主机，利用串行总线从智能温度模块、真空计等采集数据，由于这些仪表的通信接口异同，为了布线简单和维护方便，将其电平转化为RS485 电平,通过RS-485 总线传输到PLC 中，自动控制600kw 大功率直流加热电源的功率、多路高温电磁阀门的开关、50kw 真空机、进出料机构等机械设备。生产计算机通过RS232 总线实现远程监测与控制，设定运行参数与实现自动工艺编程及其优化。 按照上述的自动控制方案，经过硬件与软件调试，在实际安装使用中，系统实现了连续记录各种工艺参数以及其变化规律，通过数据库绘制工艺过程状态曲线。采用自动保存温度、真空度、电压电流等数据，为专家数据库奠定了基础。采用远程控制修改PLC 的参数、控制各阀门的启闭，调节电压升降等。对由PLC 独立进行控制或PLC 和上位机同时工作两种控制方式进行了比较分析，为集散控制的升级提供了依据。

Manual control for the majority of magnesium furnace, the operation is easy mistakes, continuous monitoring and records in accordance with the magnesium production process requirements, the development of a PLC for the control of the core production computer control system, the use of DCS industrial control design concept. the distributed control system can control and record the running state. The paper discusses the overall design of the system, MODBUS communication protocol design, analog acquisition and control program for multi-way solenoid valve.This thesis control panel wiring design, including a temperature control module, vacuum machine module, PLC variable process logic control programming of the device and the host computer program for production of computer design. PLC as the control computer, collect data from intelligent temperature module, vacuum gauge. Due to the similarities and differences of these instrument communication interface, for simple wiring and easy maintenance, its level converted to RS485 level serial bus via the RS-485 bus transfer to the PLC. It is automatic control of heating power of 600kw high-power DC power, multi-channel switch of the high temperature solenoid valve, 50kw vacuum machine, and out of the feeding mechanism and other mechanical equipment. Production of remote monitoring and control computer via the RS232 bus, set the operating parameters of the automatic process programming and its optimization. Automatic control program in accordance with the above, after the hardware and software debugging, use the actual installation. The system has a continuous recording of various process parameters and their variation, in process state curve drawn through the database. The thesis automatically saved temperature, vacuum, voltage and current data, and laid the foundation for the expert database. Remotely modify the PLC parameters can control the opening and closing of the valve to adjust the voltage scaling. A comparative analysis of independence from the PLC control or PLC and PC simultaneously two kinds of control, and provides a basis for distributed control upgrade.