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20-84 On Reference Bandwidth
Range:
Function:
5%
*
[0 - 200%]
When the difference between the feedback and the setpoint
reference is less than the value of this parameter, the frequency
converter’s display will show “Run on Reference”. This status
can be communicated externally by programming the function
of a digital output for
Run on Reference/No Warning
[8]. In ad-
dition, for serial communications, the On Reference status bit of
the frequency converter’s Status Word will be high (1).
The
On Reference Bandwidth
is calculated as a percentage of
the setpoint reference.
2.17.6. PID Controller, 20-9*
This group provides the ability to manually adjust this PID Controller. By adjusting the PID Con-
troller parameters the control performance may be improved. See section on
PID
in the chapter
Introduction to VLT AQUA Drive
in the
VLT AQUA Drive Design Guide
for guidelines on ad-
justing the PID Controller parameters.
20-91 PID Anti Windup
Option:
Function:
[0]
Off
[1]
*
On
On
[1] stops the PID Controller from integrating (adding) the
error between the feedback and the setpoint reference if it is
not possible to adjust the output frequency of the frequency
converter to correct the error. This can occur when the fre-
quency converter has reached its minimum or maximum output
frequency or when the frequency converter is stopped.
Off
[0] causes the PID Controller to continue to integrate (add)
the error between the feedback and setpoint reference even
though the frequency converter cannot adjust its output fre-
quency to correct this error. In this case, the integral term of
the PID Controller may become quite large. When the PID Con-
troller can again control the frequency converter’s output fre-
quency, it may attempt to initially make a large change in the
frequency converter’s output frequency. This should generally
be avoided.
20-93 PID Proportional Gain
Range:
Function:
0.50
*
[0.00 = Off - 10.00]
This parameter adjusts the output of the frequency converter’s
PID Controller based on the error between the feedback and the
setpoint reference. Quick PID Controller response is obtained
when this value is large. However, if too large a value is used,
the frequency converter’s output frequency may become un-
stable.
2. Parameter Description
VLT
®
AQUA Drive Programming Guide
184
MG.20.O2.02 - VLT
®
is a registered Danfoss trademark
2