1. Heating mode 'H': When the detected temperature ≤ set temperature - hysteresis temperature, the relay is turned on and the heating equipment starts working; when the detected temperature ≥ set temperature, the relay is disconnected and the heating equipment stops working; 2. Cooling mode 'C': When the detected temperature ≥ set temperature + hysteresis temperature, the relay is turned on and the cooling equipment starts working; when the detected temperature ≤ set temperature, the relay is disconnected and the cooling equipment stops working; 4. Delay OPH: After completing a normal heating or cooling work, the system starts timing T. Only when T ≥ OPH, the system can carry out round of heating or cooling; 3. High temperature alarm function ALA: When the actual temperature ≥ alarm temperature, the system turns on the sound and light alarm, and disconnects the relay, and any key stops the sound and light; 5. Temperature correction function OFE (-10.0~10.0℃): The system may have deviations when working for a long time. This function can be used to correct the actual temperature measurement temperature + calibration value;