Destaging Threshold; Staging Speed [Rpm]; Staging Speed [Hz] - Danfoss VLT Programming Manual

®
VLT HVAC Drive Programming Guide

25-43 Destaging Threshold

Range:
Application [Application dependant]
dependent*
NB!
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 RPM* [0 - 0 RPM]

25-45 Staging Speed [Hz]

Range:
0.0 Hz* [0.0 - 0.0 Hz]
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 par. 4-11
Speed Low Limit [Hz] , to the par. 4-13
High Limit [Hz] , expressed in percent.
Destaging Threshold must range from
Motor Speed Low Limit and n is Motor Speed High Limit.
HIGH
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 par. 25-42
[RPM]
.
Staging Speed is calculated with the following formula:
STAGE
%
STAGE HIGH
=
100
where n is Motor Speed High Limit and n
HIGH
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 par. 25-42
[Hz] .
Staging Speed is calculated with the following formula:
STAGE
%
STAGE HIGH
= where n
100
Staging Threshold.
MG.11.C9.02 - VLT ® is a registered Danfoss trademark
3 Parameter Description
Motor Speed Low Limit [RPM]
Motor Speed High Limit [RPM] or par. 4-14
LOW
STAGE % = × 100 % to 100%, where n
HIGH
Staging Threshold
, and par. 4-13
is the value of Staging Threshold.
STAGE100%
Staging Threshold , and par. 4-14
is Motor Speed High Limit and n
HIGH
Motor
or par. 4-12
Motor Speed
3
is
LOW
Motor Speed High Limit
Motor Speed High Limit
is the value of
STAGE100%
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