Design Of The Central Air-Conditioning System Based On PLC Control

With the continuous improvement of the cigarette production technology,the requirement on the temperature and humidity control indexes in the production area are becoming increasingly strict.However,the central air-conditioning system of the Shifang Cigarette Factory at present has low communication speed,backward control strategy and unsound monitoring function,which makes the temperature and humidity out of reliable and stable control,causing terrible waste of energy and great difficulty in meeting the demands of the industrial development and the national requirements of energy saving and emission reduction.In view of the current situation of the central air-conditioning system,this paper is going to do an optimization design,an analysis and research and technology realization of the central air-conditioning system based on PLC.It mainly includes the following procedures:(1)According to the field needs and design requirements,select the PLC controller,remote I/O modules,bus connection modules and other hardware equipment.(2)Design the self-control and energy-saving control strategies.(3)Build the network communication platform combing the ring network with the star subnet based on the C/S structure and Ether Net/IP industrial ethernet and by using the gigabit fiber and the ethernet switch.(4)The Factory Talk View configuration software and the VBA script secondary development are used to design the monitoring interface so as to realize the functions of work flow chart,equipment parameter setting,equipment start/stop control,status display,trend statement,alarm display,etc.of the central air-conditioning system.At last,it's verified by the practical operation that the above optimization design scheme can operate normally and realize the preset control function.