PLC-based Medical Pure Water Disposal System

This paper introduces the topics of the source, background, analysis of the principle of hemodialysis, hemodialysis on dialysis fluid requirements, dialysis with pure water in the blood to the important role of dialysis. System design, including process design and control system design of two parts, according to indicators of water production requirements, the system uses two reverse osmosis process, control the use of Siemens S7-300PLC to achieve automatic control, completion of the system parameters of testing, working condition control and switch, combined with the realization of constant pressure water supply inverter control. And then discusses the selection of system hardware, including the selection of instrumentation, such as temperature, flow, pressure, electrical conductivity, such as the selection of transmitter; valve selection, such as solenoid valve, electric valve, check valve of the Selection; PLC and related modules Selection. System hardware design part of a detailed breakdown of the PLC's I/O port allocation of resources, design a system block diagram and the system's hardware configuration.12 reverse osmosis system can work in the normal production of water, water supply, standby and renewable sources of raw water from the four working condition, the system is modular program design process, the realization of the function module call, in the papers listed in the program control flowchart. In addition, the system has been constant pressure water supply control, reverse osmosis in 12 normal working condition, through the water pipe is located in the middle of the electric control valve to achieve constant pressure control, water supply status in the water tank through the inverter to change the motor speed, thus Control of the middle of the constant water pressure, which is designed in detail in the paper are introduced.This project had begun the trial run and the experiment indicated:the system runs stable, and works well in different active status according to the water-output situation. Moreover it delivers high-quality purified water, satisfies the medical water request, increases the purified water output, enhances the automaticity, and saves the energy.