Danfoss VLT AQUA Programming Manual page 238

2. Parameter Description
[2]
[3]
2
25-51 Alternation Event
Option:
[0]
[1]
[2]
[3]
238
At Command
At Staging or at Com-
mand
* External
Alternation Time In-
terval
Sleep Mode
Predefined Time
MG.20.O2.02 - VLT
Lead pump alternation equalizes the use of pumps by periodi-
cally 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.
Off [0]: No alternation of lead pump function will take place. It
is not possible to set this parameter to options other that
Motor Start
if , par. 25-03, is set other than
NB!
It is not possible to select other than
Fixed Lead Pump
At Staging
[1]: Alternation of the lead pump function will take
place when staging another pump.
At Command
[2]: Alternation of the lead pump function will take
place at an external command signal or a pre-programmed
Alternation Event
event. See
At Staging or at Command
[3]: 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
At Staging or Command
[3] have been selected in
Alternation
, par. 25-50. If an Alternation Event is selected, the
alternation of lead pump takes place every time the event oc-
curs.
External
[0]: Alternation takes place when a signal is applied to
one of the digital inputs on the terminal strip and this input has
Lead Pump Alternation
been assigned to
puts
, par. 5-1*.
Alternation Time Interval [1]: Alternation takes place every time
Alternation Time Interval
, par. 25-52, expires.
Sleep Mode
[2]: Alternation takes place each time the lead
No-Flow Function
pump goes into sleep mode.
Sleep Mode
be set to [1] or an external signal applied for this
function.
Predefined Time
[3]: Alternation takes place at a defined time
Alternation Predefined Time
of the day. If
alternation is carried out every day at the specified time. Default
time is midnight (00:00 or 12:00AM depending on the time for-
mat).
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is a registered Danfoss trademark
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VLT AQUA Drive Programming Guide
Off
Direct on Line
Off
Yes
, par. 25-05, is set to [1].
, par. 25-51, for available options.
At Command
Lead Pump
Digital In-
[121] in
, par. 20-23, must
, par. 25-54, is set, the
[0]
[0].
[0] if
[2] or