General speaking, the whole control system has three performance indicators: accuracy, stability and fast. We adjust the PID parameters of the
variable frequency drive to make those three performance indicators as perfect as possible(those three indicators are constrained to each other).
PID parameter adjustment is a complex process, hence, the variable frequency drive manufacturers in order to simplify this work, they set some intuitive parameters as default, users only need to modify these parameters for debugging conveniently. Take an example of the accelerate time, you only need to adjust the accelerate time for the motor start, but you don't need to know the PID value after you set it. Another important parameter is the decelerate time, in some applications it needs fast stop time but it's not related with PID. In the debugging process, you can read rotate feedback signal from PLC to verify accuracy and stability, also you can see the time from stop to steady during the electric motor stop process to determine fast brake whether meet the requirements; In addition, you can observe the curve from software after you drag the feedback in it, it's more intuitive.
