Danfoss VLT HVAC Series User Manual

25-43 De-staging Threshold
Range: Function:
0 %* [0 - 100 %] 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 “De-staging
Speed” the fixed speed pump is de-staged. The De-staging Threshold is used to calculate the speed
of the variable speed pump when the de-staging of the fixed speed pump occurs. The calculation
of the De-staging Threshold is the ratio of par.4-11
Motor Speed Low Limit [RPM] or par.4-12 Motor
Speed Low Limit [Hz]
, to the par.4-13 Motor Speed High Limit [RPM] or par.4-14 Motor Speed High
Limit [Hz]
, expressed in percent.
De-staging Threshold must range from
STAGE %
=
LOW
HIGH
× 100 %
to 100%, where n
LOW
is
Motor Speed Low Limit and n
HIGH
is Motor Speed High Limit.
25-44 Staging Speed [RPM]
Range: Function:
0 RPM* [0 - 0 RPM] Readout of the below calculated value for Staging Speed. When adding a fixed speed pump, the
variable speed pump ramps down to a lower speed in order to prevent an overshoot of pressure.
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
Staging Threshold , and par.4-13 Motor Speed High
Limit [RPM]
.
Staging Speed is calculated with the following formula:
STAGE
=
HIGH
STAGE %
100
where n
HIGH
is Motor Speed High Limit and n
STAGE100%
is the value of Staging Threshold.
VLT
®
HVAC Drive Programming Guide 3 Parameter Description
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark 3-243
3

Danfoss VLT HVAC Series Specifications

General

Protection Features	Overcurrent, Overvoltage, Undervoltage, Overtemperature, Short circuit
Communication Interfaces	Profibus, Ethernet
Cooling Method	Forced convection
Ambient Temperature	-10°C to +40°C
Enclosure Rating	IP20, IP21, IP55
Output Voltage	0 - 100% of supply voltage