连俊

摘  要：大型煤炭及铁矿石散货码头桥式抓斗卸船机均采用自动化交流变频调速控制系统，对桥式抓斗卸船机自动化控制系统采集模拟量数据的稳定性、高效性和可靠性提出了较高的要求，文章针对桥式抓斗卸船机卸船作业环境的特点，介绍采用模拟量滤波技术，实现在电磁干扰强的作业环境下，由于瞬时电磁干扰给模拟量采集造成的扰动，消除模拟量采样值误差，满足桥式抓斗卸船机自动化控制系统对稳定性、高效性和可靠性的要求，自运行以来，工作稳定，故障率低，满足大型散货船靠泊装卸船作业需求，取得了显著的经济效益和社会效益。

关键词：S7-400H PLC;模拟量滤波;称重;桥式抓斗卸船机自动化控制

中图分类号：U653.92 文献标志码：A         文章编号：2095-2945（2020）24-0153-02

Abstract： The bridge-type grab ship unloader of large coal and iron ore bulk cargo terminal adopts automatic AC frequency-conversion and speed-regulation control system， which has posed higher requirements for the stability， efficiency and reliability of analog data collected by the automatic control system of bridge-type grab ship unloader. According to the characteristics of ship unloading environment of bridge-type grab ship unloader， this paper introduces the use of analog filtering technology to realize in the working environment with strong electromagnetic interference. Due to the disturbance caused by instantaneous electromagnetic interference to analog acquisition， the error of analog sampling value is eliminated， and the requirements of stability， efficiency and reliability of the automatic control system of bridge-type grab ship unloader are satisfied. Since the operation， the work is stable and the failure rate is low， which meets the needs of berthing， loading and unloading operations of large bulk carriers， and remarkable economic and social benefits have been achieved.

Keywords： S7-400H PLC; analog filter; weighing; automatic control of bridge-type grab ship unloader

1 概述

湄洲灣港东吴港区东吴作业区东1#、东2#泊位为大型散货码头，装卸船生产为不间断运行，桥式抓斗卸船机在抓斗进入船舱抓料作业时起升/开闭机构称重系统经常出现过载误报警，导致桥式抓斗卸船机起升/开闭机构突然停机情况，影响卸船效率。分析发现，卸船机起升/开闭机构称重传感器采用4～20毫安模拟量输出，该模拟量采样值受到电磁瞬时干扰，产生较大的扰动，采样值经SIMATIC S7 400 PLC A/D转换后，反映在PLC程序中的工程量值误差较大，引起了起升/开闭机构称重系统过载误报警停机情况，通过在PLC程序中采用模拟量滤波技术，以降低因卸船机作业瞬时干扰引起模拟量输出值变化。

2 模拟量滤波技术