Converting an Arduino PID controller to a Ramp/Soak controller

I have built a PID controller for temperature control using the PID library Arduino Playground - PIDLibrary

I am now interesting in turning it into a Ramp Soak controller, which from my understanding is essentially a PID controller with a moving Setpoint.

To create this, would it be best to use a Real Time Clock chip, such as the Maxim DS1307? Or would millis() be sufficient?

Thanks in advance :slight_smile:

The RTC would be needed if you want to configure the Arduino to do something at some fixed real-world time. If you only want it to do things after a known interval from you turning it on, pushing a button or whatever then you can do that just using the millis() function.