Seconds
Variable speed
pump
Motor speed
high limit
Destaging
speed
Motor speed
low limit
Fixed speed
pump
Motor speed
low limit
Destaging
speed
Motor speed
high limit
Seconds
Fixed speed
pump
Motor speed
high limit
Destaging
speed
Motor speed
low limit
Seconds
Controlled stop
command
activated
130BA368.10
Illustration 3.92 Destaging Speed
25-49 Staging Principle
Select the staging principle for the staging of fixed speed pumps
(direct online mode). To configure the frequency converter to
return to closed-loop operation immediately after a pump was
staged or destaged, select
[1] Rapid Staging
. Use
[1] Rapid Staging
in systems with rapid demand changes.
Option:
Function:
[0]
*
Normal
[1]
Rapid Staging
3.22.4 25-5* Alternation Settings
Parameters for defining the conditions for alternation of
the variable speed pump (lead), if selected as control
strategy.
25-50 Lead Pump Alternation
Option:
Function:
NOTICE
If
parameter 25-05 Fixed Lead Pump
is set
to
[1] Yes
, it is only possible to select
[0]
Off
.
Lead pump alternation equalizes the use of
pumps by periodically changing the pump that
is speed-controlled. This ensures that pumps are
equally used over time. Alternation equalizes the
usage of pumps by always selecting the pump
with the lowest number of hours run to stage
on next.
[0] Off
No alternation of lead pump function takes
place. It is not possible to set this parameter to
options other than
[0] Off
if
is set other than
[0]
Direct on Line
.
25-50 Lead Pump Alternation
Option:
Function:
[1] At staging
Alternation of the lead pump function takes
place when staging another pump.
[2] At
command
Alternation of the lead pump function takes
place at an external command signal or a pre-
programmed event. See
parameter 25-51 Alternation Event
for available
options.
[3] At staging
or
command
Alternation of the variable speed (lead) pump
takes place at staging or according to
[2] At
command
.
25-51 Alternation Event
Option:
Function:
This parameter is only active if the options
[2]
At Command
or
[3] At Staging or Command
have been selected in
. If an alternation event is
selected, the alternation of lead pump takes
place every time the event occurs.
[0]
*
External
Alternation takes place when a signal is
applied to 1 of the digital inputs on the
terminal strip and this input has been assigned
to
[121] Lead Pump Alternation
in
parameter
group 5-1*, Digital Inputs
.
[1] Alternation
Time
Interval
Alternation takes place every time
parameter 25-52 Alternation Time Interval
expires.
[2] Sleep Mode Alternation takes place each time the lead
pump goes into sleep mode. Set
parameter 20-23 Setpoint 3
to
[1] Sleep Mode
or
apply an external signal for this function.
[3] Predefined
Time
Alternation takes place at a defined time of the
day. If
parameter 25-54 Alternation Predefined
is set, the alternation is carried out every
day at the specified time. Default time is
midnight (00:00 or 12:00AM depending on the
time format).
25-52 Alternation Time Interval
Range:
Function:
24
h
*
[1 -
999 h]
If selecting
[1] Alternation Time Interval
in
parameter 25-51 Alternation Event
, the alternation
of the variable speed pump takes place every
time the alternation time interval expires (can be
checked in
parameter 25-53 Alternation Timer
). The timer pauses when the frequency
converter is not running.
Parameter Description
VLT
®
AQUA Drive FC 202
214
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MG20OB02
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