摘要
为了将称重数据实时传送到DCS中方便管理,本文以青岛某碱厂采集的20多种生产原料数据为例,基于自由口协议和Modbus RTU协议,设计应用了称重数据远传系统。系统由上位机、可编程逻辑控制器(programmable logic controller,PLC)和分布式控制系统(distributed control system,DCS)组成。上位机从数据库中读取数据并经过转换写入PLC内存区;DCS设有RS485接口,且只能识别Modbus RTU协议,于是DCS经RS485光纤转换器与PLC相连,实时读取PLC中的数据。本方案主要应用西门子自由口协议和Modbus协议,编写PLC内部程序,上位机方面使用VB6.0编写上位机与PLC的串行端口数据传输程序,同时应用ADO方式对结构化查询语言(structured query language,SQL)数据库进行数据操作,实现数据的查询、导出和删除。该系统已成功应用于碱厂生产现场,能够满足对数据远程实时监控的要求。
In order to transmit weighing data to DCS for real-time management,this paper takes more than 20 kinds of raw materials collected from a soda plant in Qingdao as an example,and designs a weighing data remote transmission system based on free port protocol and Modbus RTU protocol.The system consists of a host computer,aprogrammable logic controller（PLC）and a distributed control system（DCS）.The host computer reads the data from the database and writes it into the memory area of the PLC after conversion.DCS only has RS485 interface,and can only recognize Modbus RTU protocol,so DCS connects to the PLC by RS485 fiber optic converter,and read PLCreal-time data.This program mainly uses Siemens free mouth agreement and Modbus agreement,and compiles the PLC internal procedure.Host computer uses VB6.0 software to write PC and PLC serial port data transmission program,at thesame time,the ADO way is used tomanipulate the SQL database to achieve data query,export and delete.The system has been successfully applied to the soda plant production site,and can meet the requirements of remote real-time data monitoring.
作者
陈志伟
徐世许
曾祥晓
CHEN Zhiwei;XU Shixu;ZENG Xiangxiao(College of Automation and Electrical Engineering,Qingdao University,Qingdao 266071,China)
出处
《青岛大学学报（工程技术版）》
CAS
2018年第2期53-58,共6页
Journal of Qingdao University(Engineering & Technology Edition)
