Xylem IM167 R8 Aquavar CPC (Centrifugal Pump Control) - Manual (Page 113)

113
RAMP HYSTERESIS
Ramp hysteresis is the point at which the Aquavar controller changes over from the fast
ramp to the slow ramp. Default values of Ramp Hysteresis are in % of the regulation window.
The values for RAMP HYSTERESIS are automatically selected based upon the control mode
selection made during programming.
EXAMPLE: Using the same example above, the Regulation Window was 8 psig. An 80% ramp hysteresis would
be 3.2 PSIG. Note from the graph, this is 1.6 PSIG on the upper half of the regulation window, and 1.6 PSIG on
the lower half of the regulation window.
Parameter Name Value/Range Note(s)
13.05 RAMP 0-100% Pressure = 80%
HYSTERESIS Flow [Direct] = 5%
As the figure shows, Aquavar attempts to keep the actual process reading within the Setpoint
Hysteresis Window using the slow acceleration and deceleration ramp rates. When the
process reading exceeds this window, it will compensate using the fast acceleration or
deceleration ramp rates.
Adjusting Ramp Rates
Ramp 1 - Fast Acceleration: This ramp is the fast run up time used when the pump first
starts and is trying to reach the setpoint. A setting too fast may overshoot the set-point, while
a setting too slow may cause the drive to respond too slowly to set point changes. NOTE:
FOR AQUAVAR UNITS ABOVE 10 HP, SET RAMP 1 AND RAMP 2 TO AT LEAST 8 – 10
SECONDS.
Parameter
Name Value/Range Note(s)
13.01 RAMP 1 0-1800s Pressure default = 5 seconds
FAST ACCEL Level, Temperature default = 20 seconds
FEATURES
Set Point
R1
R3
R4
Set P
oint Scale
[e.g
. Pr
essu
re
- PSIG,
Flow - GPM,
etc.]
Time
R1 - Ramp 1, Fast Acceleration
R2 - Ramp 2, Fast Deceleration
R3 - Ramp 3, Slow Acceleration
R4 - Ramp 4, Slow Deceleration
Set P
oint
Hyster
esis
Window
R4 R3
Window Set
ting
% of
Set P
oint
Hysteresis -%
Hysteresis -%
R1