The Design And Implementation Of Air Conditioning Control System For Hospital Operating Room

This article takes cleaning operating room of Shengjing hospital in Shenyang as the background and design automatic control system of purity air conditioning.The system of purity air conditioning in the cleaning operating room is not only to meet the international standards for the operating pressure and air cleanliness,but also to meet the requirements of the operating room termperature and hurmidity in operation environment.Purifying air conditioning system consists of air supply unit,cycle unit,the air supplying pipe and other parts.Fresh air was take into the the operation room which was treated by air units,returning air circulation unit,filtered,heated and humidified.It will make the treatment of air heating and humidifying through the air conditioning unit with the using of electric heater,electric heating and humidifying humidifier.Low efficiency,middle efficiency and high efficiency filter air to achieve cleanliness requirements.Power device make the air flow circularly.It will realize the automatic control of cleaning air conditioning system with the control of the heating and humidifying equipment by monitoring the temperature,humidity,pressure parameters,fan inverter and all kinds of valves,Controller compares the parameters with the settings and then give the corresponding instruction,and drive the controlled object execution,finally makes the operation of the system to meet the control requirements.Siemens S7-200 series PLC was set as the controller,which realize communication with the host computer through the PROFIBUS field bus technology.PLC connect the PC and the scene sensor and actuator,which not only upload the temperature,humidity,collection field sensor differential and pressure signal parameters to the PC but also the control signal is transmitted to the PC field actuator.The design uses a host computer hot standby redundancy structure to improve the stability of the system.The host computer can make the operator to achieve online monitoring,which can also enable the engineer to control program controller update.Firstly it gives the mathematical model of the air conditioning system with the combination with the specific circumstances of the scene to design the control mode of system.Comparing control parameters and indicators through the analog and digital field sensor acquision controller.It will complete the cleaning air conditioning automatic control of each module of the system design.including air conditioning fresh air unit,cycle unit composition,each real-time monitoring,positive and negative pressure in the operation room use independent cycle unit to achieve air adjust,purification and differential pressure control.And by adjusting the air intake valve and exhaust valve opening size to achieve the operation room pressure special requirements.This system control the temperature and humidity with a PID controller PID control algorithm which is included PLC.At present,the system has been put into use in Shengjing Hospital in Shenyang.The system runs well and meet all specifications and requirements of the design,which has obtained the user acceptance.