How to collect the step response data and use it? thanks.

Hi Team，

I designed a heating circuit for a oven which is controlled by a PI regulator. a MCU sent a PWM signal to the the heating circuit, actually adjust the duty cycle of the PWM(range in 0~1023), then MCU sample the temperature of the oven.

I`d like to identify my plant from my measured data.for example, powering off my board，put it in the temperature chamber,reducing the chamber`a temperature to -40C, after power on my board, at T1 moment setting the duty cycle of the PWM to 0,monitor the temperature of the oven, wait for the oven temperature to stabilize,after the oven temperature stabilized, at T2 moment setting the duty cycle of the PWM to 900(if the duty cycle is too big, there is a over temerature protecture ) ,wait for the oven temperature to stabilize,after the oven temperature stabilized,log the all of the oven temerature information as the below picture(the horizontal axis is time/S,the vertical axis is temperature/C, record the oven temperature value interval every one second)

-->Does the log information need to preprocess or modify or not? I think that only keep all of the temperature value after T2 and delete temperature before T2, by this way the rest are the step response data,am i right?

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-->What are the value of the offset(u0) and onset lag(the red marked in the 2nd picture) during the plant identification? are the u0 -19 and the onset lag T2? am I right? thanks for your support!

Br,

Shawn Li