【作者】 赵翠琴；

【导师】 孟志强；

【作者基本信息】 湖南大学 ， 测试计量技术与仪器， 2007， 硕士

【摘要】 本论文针对石墨电极生产的需要,对石墨电极自动配料控制系统设计和开发中的关键技术进行了研究。基于MCGS工业监控组态软件,开发了一套以高性能工控机为主控制器的石墨电极配料自动控制系统。石墨电极配料自动控制系统由干粉计量、沥青计量和搅拌三个子系统组成。针对生产过程要求高可靠性的特点,本文采用工业控制计算机和PLC控制器构成典型的主从式控制系统。工业控制计算机作为主控制器,完成系统参数设置、数据管理、统计、分析、显示,配置D/A转换卡实现温度控制,配置A/D转换卡实现称重量、温度等模拟量采集。PLC通过RS-232串口与工控机通信,在工控机的调度下,完成干粉计量、沥青计量和搅拌三个子系统的动作控制。同时,在工控机中配置CAN卡,将系统组入到了公司的生产过程参数监控网。为了达到配料快速和精确的目标,重量信号采用压磁式传感器检测,本文为传感器输出信号设计了有源放大器。该放大器集信号放大和供电电源于一体,配备稳压电源,使系统精度大大提高。输出电压经V/I转换成4~20mA电流,有较强抗干扰性,适合于远距离传输。下料过程中,物料从下料口到称量小车之间存在一定的路程和下料冲击,它们都会使称重形成误差,可采用称重提前量进行补偿。但这些误差具有不确定性,为了实现较高的精确配比,论文研究与提出了一种提前量自校正算法,可有效克服随机干扰。加入搅拌锅的沥青温度是影响混捏过程的关键因素。若沥青温度低,搅拌阻力大,混捏出的糊料塑性差,不利于成型;若沥青温度过高,沥青中的轻质馏分会逐渐分解和挥发,同样降低沥青的粘结性能。本文采用模糊PID方法对计量桶中沥青进行恒温控制,提高了控制精度,取得预期效果。采用工业组态软件MCGS(Monitor and Control Generated System)作为开发平台,设计与开发了石墨电极配料自动控制系统的应用程序,论文给出了主要程序的实现技术。本系统于2006年9月在湖南银光炭素有限公司投入运行,运行结果表明本文设计的石墨电极配料自动控制系统单个料仓粉料计量误差≤3kg,沥青计量误差≤1kg,沥青温度控制误差≤2℃,系统运行可靠,达到了预定的设计要求。更多还原

【Abstract】 With the need of graphite electrode production, the thesis has carried out research on the design and development of automatic proportioning control system, and has realized it based on high reliability industry control computer and MCGS configuration software.The system is composed of powder material measurement subsystem, asphalt measurement and mixture subsystem. For the reliability requirement in the production process, the paper has supplied a set of effective master-slave resolution combining computer control with programming logic controller. Computer which works as master station carries out system parameter setting, data management, statistics analysis and display, inserted A/D cards to input anolog signals, D/A card for temperature control. The communication between computer and PLC is through by RS-232. PLC carries out action control of materiel proportioning, asphalt measuring and mixing subsystems. And the computer is installed PCI-5110 to connecte with company process parameter monitoring network exsited.The system has adopted pressure magnetism sensor to satisfy the precison measurement and rapidity, and has designed active amplifier for the sensor output signal. Because the amplifier is integrated amplifying circuit and sensors with the same power supply equipped with precise power supply, system accuracy has been improved greatly. Outputs are inverted to 4~20mA current signals which are benefit to long-distance transportation.During the process of feeding powder materials, the distance between feeder and ingredient-weighing car and striking force creat errors in weighing, which can be compensed by advancing the quantity. But the errors are robust. To realize higher accuracy, The paper proposes a self- recognizing proportioning control algorithm which is efficient to stochastic disturbance.Asphalt temperature flowed into mixer is the key factor to affect anode paste process. If asphalt temperature is low, mixing resistance becomes big and anode paste plasticity is bad; if asphalt temperature is high, asphalt has been decomposed and volatilized which also is bad to asphalt cementation. To realize temperature control, author adopts fuzzy-PID method to control asphalt temperature in measuring devices, which is benefit to improve the control precision and brings about good control results.The system adopts industry configuration software MCGS as platform, designs and develops application of automatic control system for graphite electrode proportioning. The paper proposes realization technologies of main implementation.The proportioning automatic control system had been finished and has been gone into operation in factory in September 2006. Application results show that single powder material error correction is 3kg, asphalt error correction is 1kg and asphalt temperature error correction is 2℃. The operation is stable and reliable, the prospective design specifications are implemented.更多还原