Danfoss VLT AQUA Drive FC 200 Programming Manual page 173

Parameter Description
25-50 Lead Pump Alternation
Option:
3 3
[0] Off
*
[1] At staging
[2] At
command
[3] At staging
or
command
NOTE
It is not possible to select other than [0] Off if 25-05 Fixed
Lead Pump is set to [1] Yes.
25-51 Alternation Event
Option:
[0] External
*
[1] Alternation
Time Interval
[2] Sleep Mode
[3] Predefined
Time
172
®
VLT
Function:
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 choosing the pump with the lowest
number of used hours to stage on next.
No alternation of lead pump function will
take place. It is not possible to set this
parameter to options other that [0] Off if
25-02 Motor Start is set other than [0] Direct
on Line.
Alternation of the lead pump function will
take place when staging another pump.
Alternation of the lead pump function will
take place at an external command signal or
a pre-programmed event. See
25-51 Alternation Event for available options.
Alternation of the variable speed (lead) pump
will take place at staging or the "At
Command" signal. (See above.)
Function:
This parameter is only active if the options
[2] At Command or [3] At Staging or
Command have been selected in 25-50 Lead
Pump Alternation. If an Alternation Event is
selected, the alternation of lead pump takes
place every time the event occurs.
Alternation takes place when a signal is
applied to one 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.
Alternation takes place every time
25-52 Alternation Time Interval, expires.
Alternation takes place each time the lead
pump goes into sleep mode. 20-23 Setpoint 3
must be set to [1] Sleep Mode or an external
signal applied for this function.
Alternation takes place at a defined time of
the day. If 25-54 Alternation Predefined Time,
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).
MG20O602 - VLT
AQUA Drive Programming Guide
25-52 Alternation Time Interval
Range:
24 h [1 - 999
*
h]
25-53 Alternation Timer Value
Range:
0 [0 - 0 ] Readout parameter for the Alternation Time
*
25-54 Alternation Predefined Time
Range:
Size
related 0 ]
*
25-55 Alternate if Load < 50%
Option:
[0] Disabled The lead pump alternation will take place at any
[1] Enabled The lead pump function will be alternated only if
*
NOTE
Only valid if 25-50 Lead Pump Alternation is different from
[0] Off.
25-56 Staging Mode at Alternation
Option:
[0] Slow
*
[1] Quick This parameter is only active if the option selected
in 25-50 Lead Pump Alternation is different from [0]
Off.
®
is a registered Danfoss trademark
Function:
If [1] Alternation Time Interval option in
25-51 Alternation Event, is selected, the
alternation of the variable speed pump takes
place every time the Alternation Time Interval
expires (can be checked out in
25-53 Alternation Timer Value).
Function:
Interval value set in 25-52 Alternation Time Interval.
Function:
[ 0 - If option [3] Predefined Time in
25-51 Alternation Event, is selected, the
variable speed pump alternation is carried
out every day at the specified time set in
Alternation Predefined Time. Default time is
midnight (00:00 or 12:00AM depending on
the time format).
Function:
If [1] Enabled is selected, the pump alternation
can only occur if the capacity is equal to or
below 50%. The capacity calculation is the ratio
of running pumps (including the variable speed
pump) to the total number of available pumps
(including variable speed pump, but not those
interlocked).
N RUNNING
Capacity = × 100 %
N TOTAL
For the Basic Cascade Controller all pumps are
equal size.
pump capacity.
the numbers of pumps running are providing less
than 50% of total pump capacity.
Function: