PID program is applied to the temperature control of hot air gun and soldering iron. The PID temperature correction cycle is divided into rapid 20ms, high-speed 100ms, and rapid 200ms. This program guarantees the accuracy and stability of temperature.
The PID temperature correction cycle of many YiHua high-end hot air guns is 20ms, while the soldering iron temperature correction cycle is high-speed 100ms or rapid 200ms. Because the temperature sensor is located inside the ceramic heater, a long time is required for the temperature passing to the iron mouth and then back. Therefore, high speed 100ms for each cycle is optimal control speed.
The DC power unit can be automatically converted in the case of constant voltage constant current working mode. Its status is determined through the comparison between the values of load current and limited current.
1. Constant Voltage Mode (CV)
When the current value is smaller than the set output limited current value, the power supply unit will work in constant voltage mode. Under such condition, the constant voltage indicator of front panel will light up, and the output voltage will be controlled to be the same as the set value. The current will change according to the load.
2. Constant Current Mode (CC)
If the current value is greater than the limit value of the output current, the device will work in the mode of constant current. Additionally, the constant current indicator of front panel will light up, while the output current value will be controlled no more than the set value.
Because the limited output power can not overload, the output voltage will be lower than the set point. When the output current is lower than the set value, the power unit will automatically be converted to constant current work status.