Using ATmega128 MCU and Delta temperature controller as the control core

a portable humidity generator is designed. The humidity generator is capable of producing constant temperature and humidity gas in the test chamber and is suitable for calibrating large quantities of probes in the laboratory and on the job site. The results show that the temperature measurement error of the device is not more than 0. 1 ℃

the humidity measurement error is not more than 1 % RH

the temperature control range is 5 ～ 50 ℃

and the humidity control range is 10 % RH ～ 90 % RH. The temperature and humidity are stable and fast. Multi-point calibration can be realized

which greatly improves work efficiency. Display and control operation of temperature and humidity can be completed through the LCD. It has the functions of proportion integration differentiation（ PID） parameter setting

PID parameter self-tuning

temperature and humidity multi-point correction.