25-51 Alternation Event
Option:
Function:
This parameter is only active if the options
At Command
[2] or
At Staging or Command
[3] have
been selected in par. 25-50
Lead Pump Alternation
. If an Alternation Event is selected, the alter-
nation of lead pump takes place every time the event occurs.
[0] *
External
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
Lead Pump Alternation
[121] in
par. 5-1*, Digital Inputs
.
[1]
Alternation Time Interval
Alternation takes place every time par. 25-52
Alternation Time Interval
, expires.
[2]
Sleep Mode
Alternation takes place each time the lead pump goes into sleep mode. par. 20-23
Setpoint 3
must
be set to
Sleep Mode
[1] or an external signal applied for this function.
[3]
Predefined Time
Alternation takes place at a defined time of the day. If par. 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).
25-52 Alternation Time Interval
Range:
Function:
24 h*
[1 - 999 h]
If
Alternation Time Interval
[1] option in par. 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 par. 25-53
Alternation Timer Value
).
25-53 Alternation Timer Value
Range:
Function:
0*
[0 - 0 ]
Readout parameter for the Alternation Time Interval value set in par. 25-52
Alternation Time In-
terval
.
25-54 Alternation Predefined Time
Range:
Function:
Application
dependent*
[Application dependant]
25-55 Alternate if Load < 50%
Option:
Function:
If Alternation If Capacity <50% is enabled, the pump alternation can only occurs 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).
Capacity
=
NRUNNING
NTOTAL
× 100 %
For the Basic Cascade Controller all pumps are equal size.
[0]
Disabled
The lead pump alternation will take place at any pump capacity.
[1] *
Enabled
The lead pump function will be alternated only if the numbers of pumps running are providing less
than 50% of total pump capacity.
NB!
Only valid if par. 25-50
Lead Pump Alternation
is different from
Off
[0].
2 Parameter Description
VLT
p
Automation VT Drive FC322
Programming Guide
250
MG.20.W1.22 - VLT
p
is a registered Danfoss trademark
2
Remote Site Products - 1-888-532-2706 - www.remotesiteproducts.com
http://www.remotesiteproducts.com/p-20772-Danfoss-131X8135-VLT-Automation-VT-Drive-VFD-FC322-230V-5-HP.aspx