Hi
Thanks for replay.
No there is nothing connected to board yet, so it cannot be disturbs.
I know PWM with zero-cross optocupler, but I'd like now this method. Like this I have control of direct power of heater. I have filling, that it will work better.

Hi I need to do simple thing, but I got big problem! My project is to make PID temperature control for water heater. I need to control (cut) sinusoidal. This is easy job. I have one optocuppler to detect zero cross and then after xx time open SCR I got one interpret to detect zero cross and start ti...