we are using Arduino Mega for 3D extruder at industrial robot. Is it possible that you share possibility to use hotend, temperature sensor and stepper motor with controllino? Maybe with pictures and circuit. That would be very interesting.
The relays you see on your drawing are built into a Controllino by the people who developed controllino. I have here a controlino maxi power that has relays that can do 16A.
They are indicated R0-R1-R2. you come from the mains to 1 clamp and then to the other then back to the lamp and then to the mains. Be carefull however with mains voltage, i hope you are aware of the dangers.
It is a bit a pity that this forum does not support drawings, so you can mail me at i firstname.lastname@example.org, (remove the – of the address) then i can share a drawing to make a lamp work by mail.