Danfoss VLT Series Programming Manual page 183

Parameter Description
NOTE
If the set-point is reached after staging before the variable
speed pump reaches its minimum speed - the system will
enter the state closed loop as soon as the feedback
pressure is crossing the set-point.
3 3
25-43 Destaging Threshold
Range:
Size [ 0
related - 100
*
%]
Motor speed
high limit
Destaging
speed
Motor speed
low limit
0
NOTE
If the set-point is reached after staging before the variable
speed pump reaches its maximum speed - the system will
enter the state closed loop as soon as the feedback
pressure is crossing the set-point.
25-44 Staging Speed [RPM]
Range:
0 [0 - 0
RPM RPM]
*
182
VLT
Function:
When removing a fixed speed pump, in order to
prevent an undershoot of pressure, the variable
speed pump ramps up to a higher speed. When
the variable speed pump reaches the "Destaging
Speed" the fixed speed pump is destaged. The
Destaging Threshold is used to calculate the
speed of the variable speed pump when the
destaging of the fixed speed pump occurs. The
calculation of the Destaging Threshold is the
ratio of 4-11 Motor Speed Low Limit [RPM] or
4-12 Motor Speed Low Limit [Hz], to the
4-13 Motor Speed High Limit [RPM] or 4-14 Motor
Speed High Limit [Hz], expressed in percent.
Destaging Threshold must range from
LOW
to 100%, where n
STAGE % = × 100 %
HIGH
is Motor Speed Low Limit and n
HIGH
Speed High Limit.
Variable speed
pump
Fixed speed
pump
1 3 5 Seconds
Function:
Readout of the below calculated value for
Staging Speed When adding a fixed speed
pump, in order to prevent an overshoot of
pressure, the variable speed pump ramps down
to a lower speed. When the variable speed
pump reaches the "Staging Speed" the fixed
speed pump is staged on. Staging Speed
calculation is based on 25-42 Staging Threshold,
and 4-13 Motor Speed High Limit [RPM].
Staging Speed is calculated with the following
formula:
STAGE %
STAGE = HIGH
100
MG.11.CC.02 - VLT
®
HVAC Drive Programming Guide
25-44 Staging Speed [RPM]
Range:
25-45 Staging Speed [Hz]
Range:
0.0 [0.0
Hz - 0.0
*
Hz]
LOW 25-46 Destaging Speed [RPM]
is Motor
Range:
0 [0 - 0
RPM RPM]
*
®
is a registered Danfoss trademark
Function:
where n is Motor Speed High Limit and
HIGH
n is the value of Staging Threshold.
STAGE100%
Function:
Readout of the below calculated value for Staging
Speed When adding a fixed speed pump, in order
to prevent an overshoot of pressure, the variable
speed pump ramps down to a lower speed. When
the variable speed pump reaches the "Staging
Speed" the fixed speed pump is staged on.
Staging Speed calculation is based on
25-42 Staging Threshold, and 4-14 Motor Speed High
Limit [Hz].
Staging Speed is calculated with the following
formula:
STAGE %
where n
STAGE = HIGH
HIGH
100
High Limit and n is the value of Staging
STAGE100%
Threshold.
Function:
Readout of the below calculated value for
Destaging Speed. When removing a fixed speed
pump, in order to prevent an undershoot of
pressure, the variable speed pump ramps up to
a higher speed. When the variable speed pump
reaches the "Destaging Speed" the fixed speed
pump is destaged. Destaging Speed is
calculated based on 25-43 Destaging Threshold,
and 4-13 Motor Speed High Limit [RPM].
Destaging Speed is calculated with the
following formula:
DESTAGE %
where n
DESTAGE = HIGH
100
Speed High Limit and n
DESTAGE100%
of Destaging Threshold.
is Motor Speed
is Motor
HIGH
is the value