We found that there is such a relationship, Kp/Ti = Ki；; Kp * Td = Kd

So the Time constant ti is determined by the proportional coefficient Kp and the "integral coefficient" Ki***.

In practice, we can only indirectly affect the integral and differential constants Ti and Td by adjusting Kp, Ki and Kd.

Therefore, PID parameter adjustment is difficult, skillful and requires some experience.