基于C8051F310的PCA模块在Modbus通信网络中的应用  

Application of PCA Module in the Modbus Communication Network Based on C8051F310

作　　者：王德志[1] 

机构地区：[1]包头职业技术学院电气工程系,包头014030

出　　处：《自动化与仪表》2015年第2期72-76,共5页Automation & Instrumentation

摘　　要：针对现场仪器仪表对Modbus通信网络组网的要求，该文分别从硬件设计、PCA0捕捉转换算法设计和RS485收发程序设计等方面介绍ModbusASCII码传输方式在RS485电气接口中的实现方法。以磁漩涡流量计为实验载体，利用C8051F310中PCA模块的边沿触发捕捉功能，可以实现0～10V，4～20mA模拟量或脉冲频率信号与Modbus标准协议语言间的高精度转换。该方案利用中断方式而非查询方式进行外部脉冲信号的检测．响应时间快、主从通讯容错性高、已经成功应用在磁漩涡流量计Modbus并网系统中，转换误差控制在2％以内。该方案通用性和实用性强，能够实现对大部分现场仪表传统信号转换和Modbus并网的要求。This paper introduces the method of Modbus ASCII Code transmission mode in the RS485 electrical inter- face implementation,from the level of the hardware designing,PCA0 capture conversion algorithm designing and the RS485 transceiver program designing,for field instruments to the requirement of the Modbus communication network, It can realize the high precision conversion between 0-10 V,4-20 mA analog or pulse frequency signal and the standard Modbus protocol language,by using PCA in C8051F310 edge-triggered capture function module and the experimental carrier for magnetic vortex flowmeter.The scheme using interrupt way instead of query manner to test the pulse signal,which has fast response time,high fault tolerance and high fault tolerancein master-slave communication, has been successfully used in the magnetic vortex flowmeter Modbus grid system,and the transformation error control within 2%.The scheme has strongergenerality and practicability,can achieve the most traditional signal conversion and Modbus field instruments grid requirements.

关 键 词：C8051 F310 PCA计数器/定时器 脉冲频率信号 MODBUS RS485 

分 类 号：TP273[自动化与计算机技术—检测技术与自动化装置]