浅谈公司某专用系统补压机变频器通信协议转换卡的研制

本文针对公司某专用系统补压机变频器备品短缺,同时国内主流中小容量变频器与公司某专用系统存在"通信协议障碍"的问题,提出了研制该专用系统补压机变频器通信协议转换卡的想法。本文从通信协议分析、硬件设计、软件编程三方面介绍了通信协议转换卡的研制过程,并测试成功投入系统运行,历经一年时间一切运行正常。该研制实现了国内主流中小容量变频器与该专用系统的通信,解决了该专用系统补压机变频器备品短缺的"卡脖子"技术难题,同时实现了该专用系统端通信协议的自主可控。

特种补压机机电试验装置研制

我公司现使用的补压机为上世纪60年代仿前苏联设计制造,为验证补压机的检修质量而设计了本补压机机电试验装置。本试验装置硬件采用三菱可编程逻辑控制器作为主控单元,采用国产触摸屏作为人机交互系统,并利用ABB变频器的变频作用提供补压机工作所需频率,外围辅助系统包含补压机的壳体、工作腔缓冲罐、抽空系统、冷却水循环系统以及干压缩空气系统。软件上可编程逻辑控制器内置程序可根据实际情况,按照不同的补压机自动调整试验参数,完成试验并输出试验数据。内部使用了先进的霍尔交流电流传感器测量100Hz交流电流信号。传感器将霍尔元件感应出的交流信号经过AC-DC及其他转换模块,变为4~20m A的标准直流信号输出到三菱FX2N-4AD数模扩展模块,触摸屏可以利用该信号自动计算功率。

Mechanism of burst feeding in ZL205A casting under mechanical vibration and low pressure

The burst feeding behavior of ZL205 A casting under mechanical vibration and low pressure was investigated by casting experiment and physical model. Experimental results indicated that the burst feeding appeared repeatedly during solidification and left a shrinkage cavity with layered structure under mechanical vibration. The castings with less shrinkage and higher density could be achieved through the vibration. The calculation results of physical model showed that the burst feeding could perform spontaneously under vibration while difficultly without vibration in low-pressure die casting. The obstruction of a casting could be broken and the grains could be rearranged by the vibration. And the obstruction could be carried away due to the inner and outer pressure difference, causing a burst feeding.