Control system for screw chiller based on S7200 PLC and MCGS
SHI Duo1, LU Guanghua2, SUN Songli2, YIN Jingsong3
（1.Jiangsu Chunlan Power Manufacturing Co., Ltd, Taizhou 225300, China;
2.School of intelligent manufacturing, Taizhou Institude of Sci.&Tech.,NUST., Taizhou 225300, China;
3.Engineering Training Center, Taizhou, Institude of Sci.&Tech.,NUST., Taizhou 225300, China)
 

Abstract: Aiming at the heavy energyconsumption of the central air conditioning system, by analyzing the structure and working principle, it was clear that electronic expansion valve as throttling element and the control of electronic expansion valve were the key factor to achieve energy saving and reliable operation, a control system of screw chiller based on S7200 PLC and MCGS configuration monitoring was designed. To control the superheat of refrigeration system, the incremental PID algorithm was used to control the opening of the electronic expansion valve. To realize compressor four section accommodation energy regulation, the balanced load algorithm was used .The hardware design, PLC control program and MCGS configuration software program design were completed. The results indicate that the control system has friendly manmachine interface, high intelligent level and reliable performance.
Key words: electronic expansion valve; PLC; MCGS; screw chiller; energy regulation