Design Of Ultrapure Water Control System Based On Siemens PLC

TFT (Thin Film Transistor)-LCD (liquid crystal display) is widely used in laptop,camcorders, mobile phones, digital cameras, monitors, etc. In the TFT-LCD production chain,many technological process need to use ultra-pure water;with great demand for ultra-purewater, ultra-pure water quality is directly related to the quality of TFT-LCD, ultrapure watercontrol system demand high stability, efficiency and reliability.This paper analyzes the overall process of ultra-pure water. Aim at the functions andrequirements of the automation production system; Siemens PLC technology is adopted toimprove integration of the system. The article has design software and hardware of the devicelayer, control layer, network communication. Underlying device use distributed I/O link forthe collection of input signals and output drive control, PROFIBUS field bus is adopted toensure the high reliability of signal transmission, for centralized data processing control, allthe signals were transmitted to the PLC, the control pattern of the system is hot-redunancy;and InTouch configuration software was adopted to design the the upper monitor of ultrapurewater system, the data interaction between InTouch configuration software and WinCCconfiguration software of other TFT-LCD factory automation system is realized by OPC. Onthis basis, we design the redundancy system based on S7-400H PLC.Advanced PLC redundancy technology, network technology, the fieldbus, configurationsoftware and other technology was adopt to integrating the system, its meet the requirement instability and reliability,and easy to monitor overall control system.Since put into operation,the system runs stably, it promots the automation degree of ultrapure water and strengthen theinformation interaction with factory automation system, ensure the efficiency, stability andreliability of the system, has brought good economic benefit for the enterprise.