Temperature control with pid and ssr relay

Hello, I am working on a project to control the water temperature, so the project contains 4x6kw heaters, I am thinking if it is better to control them through Pid control using ssr relay, I welcome your thoughts

ps, if anyone has any code or project with pid control and thermistor, send me if you can, thanks

e.h.

That will work but your PWM time will be much less then the PWM frequency of the Arduino. Start with a few seconds to a minute or so cycle and note how close you can hold it and if the variation is OK. You can go to an even time to keep the code simple, no need to base it on the line frequency the SSR will do the work for you. If you want to go faster then the line frequency would force you to do phase sensing and control (probably zero crossing). Zero crossing will minimize the EMI from your controller. Your SSR should have that built in.

thanks for your reply, what if i used a digital potentiometer like 'x9c104', to control ssr via 'Variable resistance control'.

I hope I did not misunderstand this work of variable resistance control :slight_smile: