I had done design and implement a PI controller by using MatLab which give me an overshoot of 25.8% and rise time of 0.09s.

Unfortunately, i had validate this controller in real-time control through Labview and gave me difference results as from simulation where the overshoot is 2.9% and rise time is 0.06s.

At 1st i told there is a scale between real time control and simulation, so i decide to work out other controller. Unfortunately, the results dint help me but make me more confused.

Below is the result of other PI controller with Ziegler Nichols method.

With Z-N open loop method, from simulation i got 71.6% but in real time i got 12.4%.

With Z-N close loop method, from simulation i got 56% but in real time i got 10.4%.

Could anyone explain to me the problem i face please?

Thankyou very much.