3.14 Main Menu - Adjustable Frequency
Drive Closed-loop - Group 20
This parameter group is used for configuring the closed-
loop PI controller that controls the output frequency of the
adjustable frequency drive.
3.14.1 20-0* Feedback
This parameter group is used to configure the feedback
signal for the adjustable frequency drive’s closed-loop PI
controller.
20-00 Feedback 1 Source
Option:
Function:
This parameter defines which input will
be used as the source of the feedback
signal.
[0]
No function
[1]
Analog Input 53
[2]
Analog Input 54
[3]
Pulse input 29
[100] Bus Feedback 1
20-01 Feedback 1 Conversion
Option:
Function:
This parameter allows a conversion function to
be applied to Feedback 1.
[0] Linear
[0] Linear
has no effect on the feedback.
[1] Square
root
[1] Square root
is commonly used when a
pressure sensor is used to provide flow feedback
(
(
flow ∝ pressure)
).
3.14.2 20-8* PI Basic Settings
Parameters for configuring the Process PI control.
20-81 PI Normal/ Inverse Control
Option:
Function:
[0] Normal Causes the adjustable frequency drive’s output
frequency to decrease when the feedback is greater
than the setpoint reference. This is common for
pressure-controlled supply fan and pump
applications.
[1] Inverse Causes the adjustable frequency drive’s output
frequency to increase when the feedback is greater
than the setpoint reference. This is common for
temperature-controlled cooling applications, such as
cooling towers.
20-83 PI Start Speed [Hz]
Range:
Function:
0 Hz
*
[ 0 -
200.0 Hz]
Enter the motor speed to be attained as a
start signal for commencement of PI control.
Upon power-up, the adjustable frequency
drive operates using speed open-loop control.
When the Process PI start speed is reached,
the adjustable frequency drive will change to
PI control.
20-84 On Reference Bandwidth
Range:
Function:
5 %
*
[0 - 200 %]
3.14.3 20-9* PI Controller
20-91 PI Anti Windup
Option: Function:
[0] Off Continue regulation of an error even when the output
frequency cannot be increased or decreased.
[1] On Cease regulation of an error when the output frequency
can no longer be adjusted.
20-93 PI Proportional Gain
Range:
Function:
0.50
*
[0 - 10 ] Enter the process controller proportional gain.
Quick control is obtained at high amplification.
However, if amplification is too great, the
process may become unstable.
20-94 PI Integral Time
Range:
Function:
20 s
*
[0.10 -
9999 s]
Enter the process controller integral time.
Obtain quick control through a short integral
time, though if the integral time is too short,
the process becomes unstable. An
excessively long integral time disables the
integral action.
20-97 PI Feed Forward Factor
Range:
Function:
0 %
*
[0 - 400 %]
Parameters
VLT
®
HVAC Basic Drive Programming Guide
MG18B222 - VLT
®
is a registered Danfoss trademark
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