摘要
本监控仪表基于Modbus协议设计,采用STC12C5A60S2高速单片机,与西门子工业PLC通信实现PLC控制与过程数据的实时在线读写显示与报警,并为工业DCS系统提供远程4～20mA工业标准电流信号输出。工作时仪表为Modbus主站,PLC为Modbus从站。采用Modbus协议,还可使本仪表用于其他支持Modbus协议的各种工业控制设备的监控。本文介绍了仪表的主要电路设计,剖析了Modbus协议细节,并给出了仪表Modbus软件的实现思路及程序代码。
The monitoring instrument is designed by STC12C5A60S2 high-speed MCU based on Modbus protocol. It can communicate with the Siemens industrial PLC, realize PLC control and process data real-time online read-write display and alarm, and provide longdistance 4-20 mA industrial standard current signal output for industrial DCS system. The instrument works as a Modbus master, while the PLC as a slave. Using of the Modbus protocol also makes the instrument monitor other various industrial control equipments support- ing the Modbus protocol. This paper describes the main instrument circuit design, reveals the detail of the Modbus protocol, and presents the instrument Modbus software scheme and program code.
出处
《单片机与嵌入式系统应用》
2012年第4期5-8,共4页
Microcontrollers & Embedded Systems
