青岛理工大学毕业设计（论文）I 摘 要中央空调已经广泛应用于商用与民用建筑中，用于保持整栋建筑温度恒定。传统的设计中， 无论季节、 昼夜和用户负荷的怎样变化，各电机都长期固定在工频状态下全速运行，所以会造成极大的的能源浪费。本设计采用变频器、 PLC、温度传感器等器件的有机结合，构成温差闭环自动控制系统，自动调节水泵的输出流量达到节能目的。该系统采用西门子的S7— 200PLC 作为主控制单元，利用传统 PID 控制算法，通过西门子MM440 变频器控制水泵运转速度， 保证系统根据实际负荷的情况调整流量，实现恒温控制，从而最大程度的解决能源浪费问题。矚慫润厲钐瘗睞枥庑赖。本设计通过采用基于USS 协议的 RS-485 总线通讯的网络，通过西门子TD200 文本显示器实现人机界面的设计，使用 MCGS 工控组态软件， 对系统进行理论分析。 通过分析该设计， 验证了该设计的可靠性， 可以解决中央空调的能源浪费问题。 聞創沟燴鐺險爱氇谴净。关键词 ：中央空调， PLC，PID，变频器青岛理工大学毕业设计（论文）II ABSTRACT The central air conditioning has been widely used in commercial and civil buildings, which are used to maintain constant temperature of the building. In traditional design, regardless of the season, day and night, and how the user load changes, the motor is fixed to run at full speed for a long time in the condition of power frequency. It will cause great waste of energy.残骛楼諍锩瀨濟溆塹籟。This design is developed based on the combination of frequency converter, PLC, temperature sensor. It makes up a temperature difference closed-loop automatic control system and automatically adjust the output flow of pump to achieve energy saving. The system adopts the Siemens S7-200 PLC as the main control unit, using the traditional PID to control algorithm, using Siemens MM440 inverter to control of pump speed, to guarantee system adjust load flow according to actual situation. All of these will bring out constant temperature control, so as to solve the...
