3.9.4 7-3* Process PID Ctrl.
7-30 Process PID Normal/Inverse Control
Option:
Function:
Normal and inverse control are implemented by
introducing a difference between the reference
signal and the feedback signal.
[0]
*
Normal Sets process control in order to increase the output
frequency.
[1]
Inverse Sets process control in order to reduce the output
frequency.
7-31 Process PID Anti Windup
Option:
Function:
[0]
Off
Continues regulation of an error even when the output
frequency cannot be increased or decreased.
[1]
*
On
Ceases regulation of an error when the output frequency
can no longer be adjusted.
7-32 Process PID Controller Start Value
Range:
Function:
0 rpm
*
[0 - 6,000
rpm]
Enter the motor speed to be attained as a start
signal for commencement of PID control.
When the power is switched on, the
adjustable frequency drive will commence
ramping and then operate under speed open-
loop control. Afterwards, when the process
PID start speed is reached, the adjustable
frequency drive will change over to process
PID control.
7-33 Process PID Proportional Gain
Range:
Function:
0.01
*
[0.00 - 10.00 ] Enter the PID proportional gain. The
proportional gain multiplies the error
between the setpoint and the feedback
signal.
7-34 Process PID Integral Time
Range:
Function:
10000.00 s
*
[0.01 -
10000.00 s]
Enter the PID integral time. The
integrator provides an increasing
gain at a constant error between the
setpoint and the feedback signal. The
integral time is the time needed by
the integrator to reach the same gain
as the proportional gain.
7-35 Process PID Differentiation Time
Range:
Function:
0.00 s
*
[0.00 - 10.00
s]
Enter the PID differentiation time. The
differentiator does not react to a constant
error, but provides a gain only when the
error changes. The shorter the PID differen-
tiation time, the stronger the gain from the
differentiator.
7-36 Process PID Differentiation Gain Limit
Range:
Function:
5.0
*
[1.0 - 50.0 ] Enter a limit for the differentiator gain (DG). If
there is no limit, the DG will increase when
there are fast changes. Limit the DG to obtain a
pure differentiator gain at slow changes, and a
constant differentiator gain where fast changes
occur.
7-38 Process PID Feed Forward Factor
Range:
Function:
0 %
*
[0 - 200
%]
Enter the PID feed forward (FF) factor. The FF
factor sends a constant fraction of the reference
signal to bypass PID control, which means that PID
control only affects the remaining fraction of the
control signal. Any change to this parameter will
thus affect the motor speed. When the FF factor is
activated it provides less overshoot, and high
dynamics when changing the setpoint.
7-38 Process PID Feed Forward Factor
is active when
is set to [3] Process.
7-39 On Reference Bandwidth
Range:
Function:
5 %
*
[0 - 200
%]
Enter the On Reference bandwidth. When the
PID control error (the difference between the
reference and the feedback) is less than the set
value of this parameter, the On Reference status
bit is high, i.e., it equals 1.
Parameter Descriptions
FC 300 Programming Guide
3-78
MG.33.MA.22 - VLT
®
is a registered Danfoss trademark
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