Hi all,
I have heater.
1. Have estimated transfer function from open loop waveform graph Labview G=0.564/303.261s+1 and time delay 10.25 sec.
2. Have calculated by Ziegler-Nichols tuning method rules parameters: Kp=64.48 , Ki=3.21 , Kd=323.26
Everything looks fine in Labview, until try same system in Matlab with same TF and PID values- graph completely different.
Question:
Why is that?
Does unity feedback line have include temp sensor or just line itself in Matlab?
Process gain must be (35.14oC – 29.5oC)/(30% – 20%) = 0.564 oC/%.Temp transmitter output must treated in % like 100%/200oC or 10volt/200oC

Help would be appreciated.

 

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