Danfoss FC 100 Series Operating Instructions Manual page 92

How to Programme the Frequ...
22-77 Minimum Run Time
Range:
0 s [Application
*
dependant]
NOTE
Does not work in cascade mode.
22-80 Flow Compensation
Option:
[0] Disabled [0] Disabled: Set-Point compensation not active.
*
7 7
[1] Enabled [1] Enabled:Set-Point compensation is active.
22-81 Square-linear Curve Approximation
Range:
100 % [0 - 100 %] Example 1:
*
NOTE
Not visible when running in cascade.
22-82 Work Point Calculation
Option:
92
Function:
Sets the time desired as minimum run time
after a normal start command (Start/Jog/
Freeze). Any normal stop command will be
disregarded until the set time has expired. The
timer will start counting following a normal
start command (Start/Jog/Freeze).
The timer will be overridden by a Coast
(Inverse) or an External Interlock command.
Function:
Enabling this parameter allows the Flow Compen-
sated Setpoint operation.
Function:
Adjustment of this parameter allows the
shape of the control curve to be adjusted.
0 = Linear
100% = Ideal shape (theoretical).
Function:
Example 1: Speed at System Design Working Point is
known:
MG.11.AD.02 - VLT
®
VLT HVAC Drive Operating Instructions
22-82 Work Point Calculation
Option:
[0] Disabled Disabled [0]: Work Point Calculation not active. To be
*
®
is a registered Danfoss trademark
Function:
From the data sheet showing characteristics for the
specific equipment at different speeds, simply
reading across from the H point and the
DESIGN
Q point allows us to find point A, which is the
DESIGN
System Design Working Point. The pump character-
istics at this point should be identified and the
associated speed programmed. Closing the valves
and adjusting the speed until H
MIN
achieved allows the speed at the no flow point to be
identified.
Adjustment of par. 22-81 Square-linear Curve Approx-
imation then allows the shape of the control curve
to be adjusted infinitely.
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 pressure Q
determined. Similarly, by plotting the design flow
(Q , Point D). the pressure H
DESIGN D
determined. Knowing these two points on the pump
curve, along with H as described above, allows
MIN
the frequency converter to calculate the reference
point B and thus to plot the control curve which will
also include the System design Working Point A.
used if speed at design point is known (see table
above).
has been
,
DESIGN
can be
RATED
at that flow can be