Design Of Measuring And Controlling System On Lye Concentration Based On Ethernet

In Chemical industry, printing and dyeing industry and Paper making industry, concentration of lye need to be censored and controlled on real time. Now, in our country, we use titration by hand. This can not reflect and control concentration of lye, on real time. It can not meet the need of the request of series production. In order to sensor and control the concentration of lye, I designed a process control system based on Ethernet to control the concentration of lye. This article first brings forward the blue print of collectivist framework which can automatic sensor and control the concentration of lye; then analyses hardware design and software design; last discuss the Industrial Ethernet realization. At first, this article introduces actuality of concentration of lye measuring, and some methods to measure the concentration of lye inside and outside the country; then expatiates the blue print of collectivist framework which can automatic sensor and control the concentration of lye, Ethernet network scheme, and style and characteristic of some kind of sensors and drivers. Second, this article analyses hardware design and software design. This measuring and controlling board collects measured signal; then analyses and calculates; Finally, controls electric machinery, pump, electromagnetism valve and liquid level switch and so on to realize the invariableness of the concentration of lye. This board realize the A/D and D/A transform, and provide LCD interface, and keyboard interface. In this part, I solved two key problems. One is that because I use squirm pump, so the precision of pumping liquid is improved; another is that because I use OPA128, so the precision of measuring and transferring signal is improved too. Then, this article discusses how to use single chip and RTL8019AS to realize the Ethernet interface. In this part, it first introduces TCP/IP protocol, and the difficulty and characteristic of how to use single chip to realize the function of Ethernet interface. Then it expatiate structure, framework and usage of RTL8019AS, and some function of TCP/IP protocol. Last it explains the realization of WEB server. This system can be browsed and controlled by web explorer. Last, the control part of this system is modeled and emulated. The result reaches our expectation. Finally it summarizes the system, brings forward some directions to improvement, prospect the development of Ethernet.