Red Lion PXU User Manual
Page 15
15
RELATIVE GAIN
.
to
.
This defines the gain of
OP2
relative to
OP1
. It is generally set to balance the
effects of cooling to that of heating(
r1d2
) or vice versa (
d1r2
). This is
illustrated in the Heat/Cool Relative Gain Figures below. After completion of
Auto-Tune, this parameter will be changed.
DEADBAND/OVERLAP
to
This defines the deadband area between the bands (positive value) or the
overlap area in which both heating and cooling are active (negative value). If a
heat/cool overlap is specified, the percent output power is the sum of the heat
power and the cool power. The function of Deadband/Overlap is illustrated in
the Control Mode Explanations.
.
b
OUTPUT 2 POWER LOWER LIMIT
.
to
.
%
This parameter may be used to limit controller power at the lower end due to
process disturbances or setpoint changes. Enter the safe output 2 low power
limit for the process. When the controller is in
USEr
or
OnOF
Control Mode, this
limit does not apply.
OUTPUT 2 POWER UPPER LIMIT
.
to
.
%
This parameter may be used to limit controller power at the upper end due to
process disturbances or setpoint changes. Enter the safe output high power limit
for the process. When the controller is in
USEr
or
OnOF
Control Mode, this limit
does not apply.
INPUT FAIL OP2 POWER LEVEL
This parameter sets the power level in the event of an input failure (open TC/
RTD or shorted RTD). Manual (
USEr
) Control overrides the input fail preset.
.
to
.
%
TEMPERATURE
COOL
HEAT
SETPOINT
100%
OP2
100%
OP1
2X PROPORTIONAL
BAND
%
OUTPUT
POWER
OP1
100%
SETPOINT
DEADBAND
NEGATIVE VALUE
COOL
RELATIVE GAIN = .5
.5
1
2
RELATIVE GAIN
OP2
100%
TEMPERATURE
HEAT
%
OUTPUT
POWER
TEMPERATURE
HEAT
SETPOINT
100%
OP2
100%
OP1
DEADBAND
POSITIVE VALUE
RELATIVE GAIN
2
1
.5
RELATIVE GAIN = .5
COOL
%
OUTPUT
POWER
HEAT/COOL RELATIVE GAIN FIGURES
Deadband/Overlap = 0
Deadband/Overlap < 0
Deadband/Overlap > 0
ON/OFF CONTROL HYSTERESIS
to
The On/Off Control Hysteresis (balanced around the setpoint) eliminates
output chatter. The control hysteresis value affects both OP1 and OP2 control.
The hysteresis band has no effect on PID Control. On/Off Control Hysteresis is
illustrated in the Control Mode explanations.
.
.
.
I
C
Shaded parameters are programming/model dependent.