Instruction manual

Cascade Controller Option
Quick Menu 022 Par. 713 Staging Bandwidth %
(STAGING BANDW%)
Value:
1 - 100%
✭ 10%
Function:
In cascade control systems, to avoid frequent switching
of fixed speed pumps, the desired system pressure
is typically kept within a bandwidth rather than at
a constant level. The staging bandwidth (SBW)
is programmed as a percentage of the setpoint
(desired pressure). For example, if the setpoint is 5
bar and the SBW set at 10%, a system pressure
between 4.5 and 5.5 bar is tolerated. No staging or
destaging will occur within this bandwidth.
Description of choice:
Set the staging bandwidth percentage to accomodate
system pressure fluctuation.
NOTE
Should the frequency converter trip for
any reason, the cascade controller can
continue operation with the remaining C/S
pumps or fans. It is recommended, however,
that the user considers a wider bandwitdth for
parameter 716, Override Bandwidth. Otherwise,
unnecessary staging could occure.
Quick Menu 023 Par. 714 SBW staging off time
(DESTAGING DELAY)
Value:
0 - 3000 sec.
✭ 30 sec.
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.
Description of choice:
Set the staging bandwidth off time delay. A delay
time of 30 seconds (factory setting) is sufficient
in most systems. When encountering frequent
staging, add to the delay time.
Quick Menu 024 Par. 715 SB W staging on time
(STAGING DELAY)
Value:
0 - 3000 sec.
✭ 30 sec.
Function:
Immediate staging of a fixed speed pump is not
desirable when a momentary pressure drop in
the system that exceeds the staging bandwidth
(SBW). Staging on 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.
MG.60.I5.22 - VLT is a registered Danfoss trademark
41
Standard Cascade
Controller Setup