Danfoss VLT AQUA Drive FC 200 Programming Manual page 178

Parameter Description
3 3 Speed
Cascade Controller
calls for another
pump
Figure 3.74 Staging
3-152
Staging
Fixed speed pump
(controlled by soft starter)
Lead pump
(controlled by freq. conv.)
t
1
P 25-40
Lead pump starts
to ramp down
MG20O622 - VLT
®
VLT AQUA Drive Programming Guide
Speed
Time
Figure 3.75 De-staging
25-42 Staging Threshold
Range:
Size
related
*
®
is a registered Danfoss trademark
Destaging
Lead pump
(controlled by freq. conv.)
Fixed speed pump
(controlled by soft starter)
t
2
P 25-41
Lead pump starts
to ramp up
Cascade Controller
prepares for
removing pump
Function:
[ 0 When adding a fixed-speed pump, to prevent
- 100 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. The
Staging Threshold is used to calculate the speed
of the variable-speed pump when the "cut-in
point" of the fixed-speed pump occurs. The
calculation of the staging 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.
Staging Threshold must range from
LOW
= × 100 %
HIGH
STAGE %
to 100%, where n is Motor Speed Low Limit
LOW
and n is Motor Speed High Limit.
HIGH
Time