Danfoss VLT AHF 005 Programming Guide

25-50 Lead Pump Alternation
Option: Function:
[0]
*
O No alternation of lead pump function takes
place. It is not possible to set this parameter to
options other that [0] O if
parameter 25-02 Motor Start is set other than [0]
Direct on Line.
[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 the At command
signal (see above).
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 parameter 25-50 Lead
Pump Alternation. 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 must be applied for
this function.
[3] Predened
Time
Alternation takes place at a dened time of the
day. If parameter 25-54 Alternation Predened
Time is set, the alternation is carried out every
day at the specied 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
Value).
25-53 Alternation Timer Value
Range: Function:
0* [0 - 7 ] Readout parameter for the alternation time interval
value set in parameter 25-52 Alternation Time
Interval.
25-54 Alternation Predened Time
Range: Function:
Size
related*
[ 0 -
0 ]
If selecting [3] Predened Time in
parameter 25-51 Alternation Event the variable
speed pump alternation is carried out every
day at the specied time set in alternation
predened time. Default time is midnight
(00:00 or 12:00AM depending on the time
format).
25-55 Alternate if Load < 50%
Option: Function:
NOTICE
Only valid if parameter 25-50 Lead Pump
Alternation is dierent from [0] O.
If selecting [1] Enabled, 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
that are interlocked).
Capacity = 
N
RUNNING
N
TOTAL
 × 100 %
For the basic cascade controller, all pumps are
equal size.
[0] Disabled The lead pump alternation takes place at any
pump capacity.
[1] * Enabled The lead pump function is alternated only if the
number of pumps running are providing less
than 50% of total pump capacity.
Parameter Descriptions Programming Guide
MG11CE02 Danfoss A/S © 03/2015 All rights reserved. 197
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Danfoss VLT AHF 005 Specifications

General

Brand	Danfoss
Model	VLT AHF 005
Category	DC Drives
Language	English