69
423
PID Proportional Gain
(PID PROP. GAIN)
Value:
0.00 to 10.00
★
0.30
Function:
The proportional gain determines the amount of speed correction that
the drive will make in response to the size of the error signal.
Used in Closed Loop, parameter 100.
Description of choice:
Quick regulation is obtained by a high gain, but, if the gain is too high,
the process may become unstable. See Optimization of the Process
Regulator for information on adjusting this.
424
PID Integral Time
(PID INTEGR.TIME)
Value:
0.01 to 9999.00 sec. (OFF)
★
OFF
Function:
The integrator adds the error signal over time and uses this to correct
the speed of the drive.
The integration time is the time needed by the integrator to have the
same effect as the proportional gain.
Used in Closed Loop parameter 100.
Description of choice:
Fast regulation is obtained by setting a short integration time. However,
if this time is too short, the process will overcorrect and become
unstable. See Optimization of the Process Regulator for information on
adjusting this.
425
PID Differentiation Time
(PID DIFF. TIME)
Value:
0.00 (OFF) to 10.00 sec.
★
OFF
Function:
The differentiator responds to the rate of change of the error signal.
The quicker the error changes, the greater the response from the
differentiator.
Used in Closed Loop, parameter 100.
Description of choice:
Fast regulation can be obtained by means of a long differentiation time.
If this time is too long, the process may overshoot. The differentiator is
generally set of OFF in HVAC appliations. See Optimization of the
Process Regulator for information on adjusting this.
426
PID Differentiator Gain Limit
(PID DIFF. GAIN)
Value:
5.0 to 50.0
★
5.0
Function:
When the differentiator is ued, fast changes in the error can sometimes
cause unstable operation. In these cases it may be useful to limit the
contribution of the differentiator.
Used in Closed Loop, parameter 100.
Description of choice:
A lower limit will improve stability, but will reduce the effect of the
differential.
427
PID Lowpass Filter Time
(PID FILTER TIME)
Value:
0.01 to 10.00
★
0.01
Function:
Noise on the feedback signal can be reduces by the lowpass filter.
Used in Closed Loop, parameter 100.
Description of choice:
Select the desired time constant (t).
The cut off frequency equals ½
π
t. For example, if a time constant of 0.1
s is programmed, the cut off frequency for the lowpass filter will be 1/
(2
π
(.1)) = 1.6 Hz.
The PID controller will then
only respond to changes in
the feedback signal whose
frequency is less than 1.6
Hz.
✭
Indicates default parameter. Depending upon the application, the drive may be delivered with other parameters selected.
