MATLAB: Raw Data to Import in System Identification

Question

Greetigns All,

I'm fresh into System Identification and PID tunning. I have one muddy point before I get started.

So, what I understand so far is System Identification allows me to identifty a transfer function for a system given its measured controller input and output data. In my plant, I use PI ProcessDatabook that gives me controller output/input time domain data in (%). Do I need to convert the data to mA signals before importing to Matlab? Like 100% would be 20 mA and 0% would be 4 mA?

Thanks All,

Ali

Answer 1

Hi,

From the specific example of Identifying the transfer function of the system, I suggest converting the input and output data to the absolute values as while learning the transfer function, the model need absolute error between outputs that is estimated.

You can look more about transfer function estimation using System Identification Toolbox using below link:

https://www.mathworks.com/products/sysid/features.html#model-identification-from-data

https://www.mathworks.com/help/ident/ug/how-to-estimate-transfer-function-models-in-the-system-identification-app.html