Danfoss VLT AQUA Drive FC 200 Instruction Manual page 92

How to program the adjustab...
22-80 Flow Compensation
Option: Function:
[0] Disabled [0] Disabled: Setpoint compensation not active.
*
[1] Enabled [1] Enabled: Setpoint compensation is active.
Enabling this parameter allows the Flow
Compensated Setpoint operation.
22-81 Square-linear Curve Approximation
Range:
100 % [0 - 100 %]
*
NOTE!
Not visible when running in cascade.
H (head)
Control Curve
22-82 Work Point Calculation
Option: Function:
Example 1: Speed at system design working point
is known:
H(head)
HDESIGNSetpoint
HMIN
P22-83/
P22-84
Control Curve
P22-87
From the data sheet showing characteristics for
the specific equipment at different speeds, simply
reading across from the H
Q point allows us to find point A, which is
DESIGN
the system design working point. The pump
characteristics at this point should be identified
and the associated speed programmed. Closing
the valves and adjusting the speed until H
been achieved allows the speed at the no flow
point to be identified.
Adjustment of 22-81 Square-linear Curve Approxi-
mation then allows the shape of the control curve
to be adjusted infinitely.
VLT AQUA 12-Pulse High Power Instruction Manual
Function:
Q ( ow)
A
point and the
DESIGN
has
MIN
®
MG.20.Y1.22 - VLT is a registered Danfoss trademark
22-82 Work Point Calculation
Option: Function:
Example 2:
Speed at system design working point is not
known: Where the speed at system design
working point is unknown, another reference point
on the control curve needs to be determined by
means of the data sheet. By looking at the curve
for the rated speed and plotting the design
pressure (H , Point C), the flow at that
DESIGN
pressure Q can be determined. Similarly, by
RATED
plotting the design flow (Q
pressure H at that flow can be determined.
D
Knowing these two points on the pump curve,
along with H described above, allows the
MIN
adjustable frequency drive to calculate the
reference point B and thus to plot the control
curve that will also include the system design
working point A.
H (head)
H RATED
P22-88
H DESIGN
Setpoint
H MIN
P22-83/
P22-84 Control Curve
P22-87
[0] Disabled Disabled [0]: Work point calculation is not active.
To be used if speed at design point is known (see
*
table above).
[1] Enabled Enabled [1]: Work point calculation is active.
Enabling this parameter allows the calculation of
the unknown System Design Working Point at
50/60 Hz speed, from the input data set in
22-83 Speed at No-Flow [RPM] 22-84 Speed at No-
Flow [Hz], 22-87 Pressure at No-Flow Speed,
22-88 Pressure at Rated Speed, 22-89 Flow at Design
Point and 22-90 Flow at Rated Speed.
22-84 Speed at No-Flow [Hz]
Range: Function:
50.0 [0.0 - Resolution 0.033 Hz.
Hz par. 22-86
*
The speed of the motor at which flow has
Hz]
effectively stopped and minimum pressure
H is achieved should be entered here in
MIN
Hz. Alternatively, the speed in RPM can be
entered in 22-83 Speed at No-Flow [RPM]. If it
has been decided to use Hz in 0-02 Motor
Speed Unit, then 22-86 Speed at Design Point
[Hz] should also be used. Closing the valves
and reducing the speed until minimum
pressure H
MIN
value.
, Point D), the
DESIGN
D B
A
C
Q
Q DESIGN Q RATED
P22-89 P22-90
is achieved will determine this
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