DCS Used In Air Condition System Of A Clean Factory Building

Along with the development of science and technology, the quality of people’s life raise increasingly and they pay more attention to health. Our government is also strict with the management of the drugs and carries out’Good Manufacturing Practice’, GMP. Simultaneously the development of pharmaceutical industry, clean workshop has become an important technology. This paper is deal with the technology of environment control in the production of the new workshop of a company.The control system of the environment of the workshop will put the automatic control of temperature and humidity, differential pressure into effect to meet the requirement of GMP.Because of the requirement of the workshop and the distance of field devices and controllers, the system must be advanced, reliable, economical. Then we choose the distributed control system(DCS) that depends on STEP7and WinCC to meet the control of the environment of the workshop.First of all, this paper discusses the advantages and disadvantages of four kinds of control systems, then we choose the DCS control system with centralized management and decentralized control, because this control system meets the workshop environment. Then, according to the requirement of temperature and humidity, differential pressure,this paper will give a brief introduction to the basic principles of air conditioning system and will give a specific introduction to the characteristic of the wet air.Finally, according to the characteristic of the wet air and the h-d chart, this paper proposes a method to separate the temperature and humidity and proposes a method to control the differential pressure depending on the volume and speed of the air. At the same time, this paper will give a brief introduction to the PID control principle and so on.According to the control requirement of the workshop environment, this control system will use the DCS control system and the field bus technology, so that this system can centralized manage and decentralized control the field devices. This system will optimize the control of the temperature and humidity through cascade control and split control and this system will monitor the field devices real-time through WinCC. Finally, This system has been put into use and runs well.