Bell & Gossett 10-001-275 XLS Integrated Pump Controller - Manual (Page 22)

22
Trigger Pressure:
Line Fill Mode will trigger below this pressure
(Percentage of setpoint) when powering up or
entering “Auto” from Off mode.
Max Combo:
Controls how many pumps can run under these
conditions by limiting the max combo of the station in
line fill.
Speed step:
Controls how much the speed of the VFD is
increased during each step.
Steady time:
Controls how long pressure and flow must be
“Steady” before continuing to the next step.
Deadband (psi):
How large of a pressure swing is considered
“Steady”.
Deadband (gpm):
How large of a flow swing is considered “Steady”
Fault Time:
How long before the systems faults, if pressure and
flow cannot reach what is considered “Steady”.
Ramp Up
Step (psi):
During ramp-up, the # of psi the system will step up.
See “Step (sec)”. Normally set to 1 psi.
Step (sec):
During ramp-up, the time between ramping the
setpoint. Normally set to 4 sec.
dP/dT Control
Enable (Checkbox):
Controls whether the “dP/dT” pump start/stop control
functionality is utilized. Check to utilize the rate of
pressure drop when starting/stopping pumps.
Start/Stop Inhibit:
The rate at which the system will inhibit pump starts
or stops as the pressure rises or drops during the
decision process. Generally 0.5-1.0 is adequate to
reduce pump cycling.
PM Skip:
Controls how much pressure drop will cause the
system to automatically skip the PM Pump in the
sequence. Fast pressure drop indicates a large
demand has suddenly been applied to the irrigation
system. This is used to detect the need to skip the
small pressure maintenance pump so that the main
pump can meet this demand as quickly as possible,
avoiding unnecessary pressure dips. Start with
values at 1.0 and monitor. To disable this feature but
continue to use the Start/Stop inhibit system above,
set this value to 10 or greater.
dP/dT Inhibit (sec):
After the main pump stops, systems will often
experience short pressure dips that may cause the
PM Skip system to restart the main pump. Set this
value to 20 seconds to prevent the PM Skip process
from restarting the main pump within this period of
time.
Current dP/dT
These values are shown to assist in tuning the
dP/dT system.
DFLC
This screen is the same as found in the SETPOINT
section detailed earlier.
Combos
This screen allows you to configure various options in a
combo.
Figure 5 1 : Combo Home Screen
Select the maximum number of combos (up to eight). For
Combo 0, which is the ‘no pump’ combo, all values
except Overlap gray out. A brief description of all
parameters follows.