基于PLC的双向地衡无人值守称重系统的设计与实现

为提高石油化工品在定量装卸过程中称重计量的精准度、作业效率和优化人力资源，避免人工计量的各种弊端，提出了双向地衡无人值守称重系统的设计和实现方法。该系统主要由地衡、红外光栅、IC读卡器、摄像头及道闸等设备组成，根据双向地衡称重系统的特点，详细阐述了其自动控制流程，利用Micro850控制器对现场I/O数据、IC卡号和称重数据进行采集，采用对质量信号进行2次滤波的方法解决称量过程中数据不稳定、计量误差大的问题。设计开发了地衡无人值守称重系统管理界面，加强了对现场操作的监管。通过验证可知，该滤波算法能将计量误差控制在3‰以内，符合工业计量要求。该系统已投入实际应用，在构建储运系统自动化、信息化和管控一体化的过程中，地衡无人值守称重系统作为其不可或缺的子环节，实现了分散过磅、集中管理的设计目标，具有极大的应用价值。

Design and implementation of bidirectional weighbridge unattended weighing system based on PLC

In order to improve accuracy and operational efficiency of petrochemical product weighing in the process of ration loading and unloading, optimize human resources and avoid all kinds of disadvantages of hand gauge, the design and implementation method of the bidirectional weighbridge unattended weighing system is proposed. The system was mainly comprised of weighbridges, infrared gratings, IC cards, cameras, barrier gates and so on. Based on the characteristics of the bidirectional weighbridge unattended system, the automatic control process was described in detail. The Micro850 controller was used to collect I/O field data, IC cards' numbers and the weighing data. The method of twice filtration was adopted to deal with the problem of data instability and large measurement errors in weighing process. Meanwhile, the weighbridge unattended system management interface was developed to strengthen supervision on site operation. The verification result indicated that the filtering algorithm could control weighing errors within 3‰, which met the requirements of industrial metrology. The system was put into practice. As an indispensable subunit, the weighbridge unattended system can realize the design goal of decentralized weight and centralized management in the process of building the storage and transportation system's automation, informatization and management control integration, which is of great application value.