Danfoss VLT FC 100 Series Programming Manual page 197

Parameter Description
25-56 Staging Mode at Alternation
Option: Function:
This parameter is only active if the option selected
3 3
in 25-50 Lead Pump Alternation is different from Off
[0].
Two types of staging and de-staging of pumps are
possible. Slow transfer makes staging and de-staging
smooth. Quick transfer makes staging and destaging
as fast as possible; the variable-speed pump is just
cut out (coasted).
[0] Slow At alternation, the variable-speed pump is ramped
*
up to maximum speed and then ramped down to a
stand still.
[1] Quick At alternation, the variable-speed pump is ramped
up to maximum speed and then coasted to stand
still.
The figure below is an example of slow transfer staging.
The variable-speed pump (top graph) and one fixed-speed
pump (bottom graph) are running before the staging
command. When the Slow [0] transfer command is
activated, an alternation is carried out by ramping the
variable-speed pump to 4-13 Motor Speed High Limit [RPM]
or 4-14 Motor Speed High Limit [Hz], and then decelerated
to zero speed. After a "Delay Before Starting Next Pump"
(25-58 Run Next Pump Delay), the next lead pump (middle
graph) is accelerated and another original lead pump (top
graph) is added after the "Delay Before Running On Line
Power" (25-59 Run-on Line Delay) as a fixed-speed pump.
The next lead pump (middle graph) is decelerated to
Motor Speed Low Limit and then allowed to vary speed to
maintain system pressure.
Figure 3.80
3-170
®
VLT HVAC Drive Programming Guide
25-58 Run Next Pump Delay
Range:
0.1 s
*
25-59 Run-on Line Delay
Range:
0.5 s
*
3.23.5 25-8* Status
Readout parameters informing about the operating status
of the Cascade Controller and the pumps controlled.
25-80 Cascade Status
Range:
0
*
25-81 Pump Status
Range:
0 [0 -
*
0 ]
MG11CD22 - VLT ® is a registered Danfoss trademark
Function:
[0.1 - This parameter is only active if the option
5.0 s] selected in 25-50 Lead Pump Alternation, is
different from Off [0].
This parameter sets the time between stopping
the old variable speed pump and starting
another pump as a new variable speed pump.
Refer to 25-56 Staging Mode at Alternation, the
figure for description of staging and
alternation.
Function:
[ par. This parameter is only active if the option
25-58 - 5.0 selected in 25-50 Lead Pump Alternation, is
s] different from Off [0].
This parameter sets the time between
stopping the old variable-speed pump and
starting this pump as a new fixed-speed
pump. Refer to Figure 3.80 for description of
staging and alternation.
Function:
[0 - 0 ] Readout of the status of the Cascade Controller.
Function:
Pump status shows the status for the number of
pumps selected in 25-06 Number Of Pumps. It is a
readout of the status for each of the pumps
showing a string, which consists of pump number
and the current status of the pump.
Example: Readout is with the abbreviation like "1:D
2:O" This means that pump 1 is running and speed
controlled by the Adjustable frequency drive and
pump 2 is stopped.