The main object of control is the air temperature and humidity or dew point temperature at the outlet of dehumidifier, which only depends on the temperature and humidity of inlet air and the control of regeneration energy. In terms of electrical control, through the comparison of traditional relay contact control, single chip microcomputer control and PLC control, it is found that the advantages of PLC control are as follows:

(1) high reliability and strong anti-interference ability

(2) it can realize the integration of electric control (logic control), electrical instrument (process control) and electric junction (motion control)

(3) the programming is simple, the use is convenient, the control program is changeable and has good flexibility

(4) small size, light weight and low power consumption.

The dehumidifier system is controlled by PLC, and the optimal temperature and humidity control accuracy is plus or minus 1 degree Celsius / plus or minus 5%.