双螺杆塑料造粒机组集散控制系统设计

Expandable Distributed Control System Design and Application in Two Screw Extruder Assembly

设计了基于串行总线结构的开放型集散控制系统 ,采用 RS4 85协议进行主机与分布式智能控制单元之间的远距离通讯和控制。对集散控制系统中的硬件配置、软件结构、协议实现和系统扩展等问题进行了详细的讨论 ,实现了双螺杆塑料挤出造粒机组中温控、电机和计量子系统的集散管理与控制。论文还针对机组温控系统的大滞后问题 ,通过对温控区间的合理分段 ,将积分分离PID控制算法与经验和逻辑判断相结合 ,提出了改进的非线性控制策略 ,显著提高了温度控制效果。

An expandable distributed control system for two screw plastic extruder assembly is presented. Serial input output (SIO) bus and RS485 protocol are used for the telecommunication and control between the host and the distributed smart temperature control units. System configuration, software structure, distributed communication and system expansion strategy are discussed in detail. With regard to the prominent hysteresis effect of the temperature regulation segments, an improved non linear control strategy is proposed based on integration separation PID algorithm, logical judgement and experimental data according to the deviation from the temperature set point. The expandability of DCS has been practically proved. Operation demonstrates that the performance of the control system has been improved evidently.