基于Profibus-DP的PLC与PC现场总线控制系统

目前。石油化工行业中使用的微机发油控制系统大都采用自行开发的单片机系统控制油泵．并通过RS一485总线与PC机的串口(使用RS-232转485转换器)相连。依靠上位机管理软件监控下位机。但化工行业中的设备复杂．且RS-485总线方式抗干扰性弱，使得系统稳定性下降．调试复杂。本系统采用PROFIBUS—DP现场总线技术．下位机为抗干扰性极强的PLC．上位机通过专用PROFIBUS通讯卡CP5611构建的整套系统．分布性、可靠性与可扩展性都得到了极大的提高。本文章通过结合现行开发的基于PROFIBUS—DP的石油化工发油控制系统．主要介绍了现场总线技术，以及如何实现PROFIBUS总线与PLC通讯的相关技术。

Field Bus Control System Based on Profibus-DP for PLC and PC

At present,the microcomputer hair-oil control system used in petrochemical industry,relying on upper system managing software ' s monitoring lower system through the connection between the RS-485bus and serial port in PC,mostly adopts the self-designed SCM system to control oil pump.However,the equipments' complexity in petrochemical industry and the weak ability of RS-485bus in disturbance suppression lead to the declining of system stability and the complication of debugging.This system adopts the PROFIBUS-DP Fieldbus technology in which lower system is PLC that is not easy to be disturbed and upper system constructs the whole system through the special PROFIBUS communication card,CP5611,which results in the huge increasing of distribution,reliability and expansibility.This article mainly introduces the way to realize the communication between the PROFIBUS bus and PLC,using fieldbus technology combined now-tapped petrochemical hair-oil control system based on Profibus-DP.