Danfoss VLT FC 100 Series Programming Guide

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 alternation 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 Inter-
val
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, No-Flow Function , 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 Alternation Event , par. 25-51, is selected, the alternation of the variable
speed pump takes place every time the Alternation Time Interval expires (can be checked out in
Alternation Timer
Value
, par. 25-53).
25-53 Alternation Time Value
Option: Function:
0 N/A Readout parameter for the Alternation Time Interval value set in par. 25-52.
25-54 Alternation Predefined Time
Range: Function:
00:00 * [00:00 – 23:59]
If option
Predefined Time [3] in Alternation Event , par. 25-51, 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).
25-55 Alternation if Capacity < 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 =
N
RUNNING
N
TOTAL
×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].
3. Parameter Description VLT
®
HVAC Drive Programming Guide
218 MG.11.C5.02 - VLT
®
is a registered Danfoss trademark
3

Danfoss VLT FC 100 Series Specifications

General

Brand	Danfoss
Model	VLT FC 100 Series
Category	DC Drives
Language	English