how to detect the dead time

[emilien]

https://pidtuner.com/#/z43RQXggYC

Here my data. As you can see at the begining, there is à dead time. but the automatic proccess doesn’t seems to take it on. I’have try these parameterse, but it is really unstable.

Are my data good ? or it’s because my proccess take a  lot of time ?

 

thanks.

[pidtuner]

Your data does not show any delay, the process is responding immediately to an input change.

If you want the tool to detect a dead-time, it must be able to see the dead time.

I.e. if your process had a dead-time, it would have a flat output during the dead-time after a change in the input.

[emilien]

Ok, the data is the evolution of the temperature of an oven. At the beginning, there is a curve which looks like an exponential (between 0 and 250s) then the curve which is found by the automatic process.

the inflection point is at the beginning.

I tried automatic PID settings and it does very bad things. The Ki is obviously much higher.

Do you have any idea how to do a much finer definition of the parameters?

Thanks.

[pidtuner]

Here are a few tips:
https://github.com/pidtuner/pidtuner.github.io/blob/master/assets/doc/PID%20Tuner.pdf
It all boils down to having good (noise and perturbation free) step response data.

[Author]

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