Danfoss VLT Series Programming Manual page 181

Parameter Description
25-23 SBW Staging Delay
Range:
15 [1 -
s 3000 s]
*
3 3
25-24 SBW Destaging Delay
Range:
15 [0 -
s 3000 s]
*
25-25 OBW Time
Range:
10 [0 -
s 300 s]
*
180
Function:
Immediate staging of a fixed speed pump is not
desirable when a momentary pressure drop in the
system exceeds the Staging Bandwidth (SBW).
Staging is delayed by the length of time
programmed. If the pressure increases to within
the SBW before the timer has elapsed, the timer is
reset.
Function:
Immediate destaging of a fixed speed pump is not
desirable when a momentary pressure increase in
the system that exceeds the Staging Bandwidth
(SBW). Destaging is delayed by the length of time
programmed. If the pressure decreases to within
the SBW before the timer has elapsed, the timer is
reset.
SB W destage dela y
Function:
Staging a fixed speed pump creates a momentary
pressure peak in the system, which might exceed
the Override Bandwidth (OBW). It is not desirable
to destage a pump in response to a staging
pressure peak. The OBW Time can be programmed
to prevent staging until the system pressure has
stabilized and normal control established. Set the
timer to a value that allows the system to stabilize
MG.11.CC.02 - VLT
®
VLT HVAC Drive Programming Guide
25-25 OBW Time
Range:
25-26 Destage At No-Flow
Option:
[0] Disabled
*
[1] Enabled
25-27 Stage Function
Option:
SB W
[0] Disabled
S etpoin t
[1] Enabled
SB W
25-28 Stage Function Time
Range:
15 s
*
300 s]
®
is a registered Danfoss trademark
Function:
after staging. The 10 second factory setting is
appropriate in most applications. In highly
dynamic systems, a shorter time may be desirable.
OBW
SBW
Setpoint
SBW
OBW
OBW timer
Function:
The Destage at No-Flow parameter ensures that
when a no-flow situation occurs, the fixed speed
pumps will be destaged one-by-one until the no-
flow signal disappears. This requires that No Flow
Detection is active. See parameter group 22-2*.
If Destage at No-Flow is disabled the Cascade
Controller does not change the normal behavior
of the system.
Function:
If the Stage Function is set to Disabled [0],
25-28 Stage Function Time will not be activated.
Function:
[0 - The Stage Function Time is programmed to avoid
frequent staging of the fixed speed pumps. The
Stage Function Time starts if it is Enabled [1] by
25-27 Stage Function, and when the variable
speed pump is running at Motor Speed High Limit,
4-13 Motor Speed High Limit [RPM] or 4-14 Motor
Speed High Limit [Hz], with at least one fixed
speed pump in the stop position. When the
programmed value of the timer expires, a fixed
speed pump is staged.
Actual head