Delta VFD300C43S-HS User Manual page 411

The smaller the integral time, the stronger integral action. It is helpful to reduce overshoot and
oscillation for a stable system. Accordingly, the speed to lower the steady-state error decreases.
The integral control is often used with the other two controls for the PI controller or PID
controller.
 Sets the integral time of the I controller. When the integral time is long, there is a small I
controller gain, with slower response and slow external control. When the integral time is short,
there is a large I controller gain, with faster response and rapid external control.
 When the integral time is too short, it may cause system oscillation.
 Set Integral Time to 0.00 to disable Pr. 08-02.
Differential Time (D)

Settings
 Use the differential controller to show the system error change, as well as to preview the change
in the error. You can use the differential controller to eliminate the error in order to improve the
system state. Using a suitable differential time can reduce overshoot and shorten adjustment
time; however, the differential operation increases noise interference. Note that a too large
differential causes more noise interference. In addition, the differential shows the change and
the output is 0 when there is no change. Note that you cannot use the differential control
independently. You must use it with the other two controllers for the PD controller or PID
controller.
 Sets the D controller gain to determine the error change response. Using a suitable differential
time reduces the P and I controllers overshoot to decrease the oscillation for a stable system. A
differential time that is too long may cause system oscillation.
 The differential controller acts on the change in the error and cannot reduce the interference. Do
not use this function when there is significant interference.
Upper Limit of Integral Control

Settings
 Defines an upper bound for the integral gain (I) and therefore limits the master frequency. The
formula is: Integral upper bound = Maximum Operation Frequency (Pr. 01-00) x Pr. 08-04 %.
 An excessive integral value causes a slow response due to sudden load changes and may
cause motor stall or machine damage.
PID Output Command Limit

Settings
 Defines the percentage of the output frequency limit during the PID control. The formula is
Output Frequency Limit = Maximum Operation Frequency (Pr. 01-00) x Pr. 08-05 %.
0.00–1.00 sec.
0.0–100.0%
0.0–110.0%
12.1-08-5
Chapter 12 Description of Parameter SettingsC2000-HS
Default: 0.00
Default: 100.0
Default: 100.0