The PID solution was very good, but now I need help to find transfer function of PT1 (similar equation like the PID equation)
Thanks

 

Hi,
try
Y = X * (1 - e^(-t/TC))

with X = input signal (0-100%), t = time, TC = time constant in same units as t. The result Y (0-100%) will be equal to X after an infinit time.
Good luck.