Technical information

H
DESIGN
(Required pressure) is the setpoint for closed loop
(PI) operation of the frequency converter and is set as for
closed loop operation without flow compensation.
It is recommended to use slip compensation and RPM as
unit.
130BA383.11
NOTE
When flow compensation is used with the Cascade
Controller (parameter group 25-**), the actual set-point will
not depend on speed (flow) but on the number of pumps
cut in. See below:
Set Point
P22-87
Number of pumps
H
(head)
H
DESIGN
H
MIN
130BA547.10
21 3
There are two methods which can be employed,
depending upon whether or not the Speed at System
design Working Point is known.
Parameter used
Speed at
Design Point
KNOWN
Speed at
Design Point
UNKNOWN
Cascade Controller
22-80 Flow Compensation
+ + +
22-81 Square-linear Curve Approximation
+ + -
22-82 Work Point Calculation
+ + -
22-83 Speed at No-Flow [RPM]/22-84 Speed at No-
Flow [Hz]
+ + -
22-85 Speed at Design Point [RPM]/22-86 Speed at
Design Point [Hz]
+ - -
22-87 Pressure at No-Flow Speed
+ + +
22-88 Pressure at Rated Speed
- + -
22-89 Flow at Design Point
- + -
22-90 Flow at Rated Speed
- + -
22-80 Flow Compensation
Option: Function:
[0] * Disabled Set-Point compensation not active.
[1] Enabled Set-Point compensation is active. Enabling this
parameter allows the Flow Compensated Setpoint
operation.
22-81 Square-linear Curve Approximation
Range: Function:
100 %* [0 - 100 %] Example 1:
Adjustment of this parameter allows the
shape of the control curve to be adjusted.
0 = Linear
100% = Ideal shape (theoretical).
NOTE
Not visible when running in cascade.
Parameter Description
VLT
®
HVAC Drive Programming Guide
156 MG11CD02 - VLT
®
is a registered Danfoss trademark
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