It is normal for C210 and 24V supply. Minimum duty cycle is one mains period (or 18ms for DC supply) and it is too much of a power. You can drive it with 12V supply for better stability.
Hi, I connected the 12v power supply and it works great . The Temperature is now stable +- 2 °C
Thank you very much Sparkybg for sharing your knowledge with us,thanks to all the members who helped me a lot in building this wonderful Controller. I made the controller and it works pretty well,but I have the following problem: I calibrated the controller with a precision 10 Ohm resistor 0.1% as stated in the instruction but I have a problem with temperature stabilization.For example when I set the temperature to 350 ° C - The temperature varies between 340 ° C and 360 ° C. The temperature is very volatile. The controller does not precisely regulate the temperature. I use the solder Iron JBC T210-A .Please help me?