PID Ziegler–Nichols Tuning metod?

[asrock70]

I have an electric oven,I used CMSIS-PID for the MCU-
I am trying to figure out how to tune the PID-
I want to try first.
Ziegler–Nichols Tuning Method S-shaped Step Input Response Curve-
You are not sure about one little thing-
How do I get the S curve?
Just turn on the furnace without regulation and record the temperature in the furnace, for example 1x per second?

Thanks

 

[FvM]

Just turn on the furnace without regulation and record the temperature in the furnace, for example 1x per second?

Yes.

--- Updated Jun 15, 2023 ---

Depending on heater power and unregulated end temperature, it may be necessary to observe the step response with reduced constant power.

 

[asrock70]

When must performance be limited?
When the power is significantly higher than the losses at the desired max temperature and the curve would not tend to flatten?
This will not be my case, the furnace is built with insulation material +1600C, heat loss through penetration at 1000 C is approx. 1.5 kW, the output of the SiC heating elements is 4 to 5 kW.
Honestly, I'm curious to what maximum temperature I will get