VCC-X Operator Interface SD
VCC-X SETPOINTS
47
Setpoint Screen #22 - Stage Off Window -
Cooling/Heating
VCC-X Spts ID:#
Stage Off Window
Cooling: 5.0
º
F
Heating: 5.0
º
F
When the VCC-X Controller is in Cooling Mode, if the Supply Air
Temperature drops below the Active Supply Air Cooling Setpoint
minus the Cooling Stage Off Window value, a Cooling Stage will be
deactivated after its Minimum Run Time. In the Heating Mode, if the
Supply Air Temperature rises above the Active Supply Air Heating
Setpoint plus the Heating Stage Off Window value, a Heating stage
will be deactivated after its Minimum Run Time.
Description
Minimum
Default
Maximum
Stage Off Window Cooling
1ºF
(.6
º
C)
5ºF
(2.8
º
C)
30ºF
(16.6
º
C)
Stage Off Window Heating
1ºF
(.6
º
C)
5ºF
(2.8
º
C)
50ºF
(27.7
º
C)
Setpoint Screen #23 - Mod Heat Proportional
Window and Time Period
VCC-X Spts ID:#
Mod Heat
Prop Window: 10.0
º
F
Time Period: 30s
The Modulating Heating Proportional Window is the control range
of the Modulating Signal above and below the Active Supply Air
Temperature Setpoint. The size of the Proportional Window will
determine how much of a signal change the controller will make
per Time Period for every 1
˚
F the Supply Air Temperature is from
setpoint. The maximum signal change per time period is 10% which
occurs when the Supply Air Temperature is the full Proportional
Window amount from setpoint. So, with a 5
˚
Proportional Window,
if the Supply Air Temperature is 5
˚
or more from setpoint, the signal
change will be 10% per time period. At 4
˚
difference, the signal
change will be 8% per time period. By the time the difference is 1
˚
,
the signal change will be 2% per time period. With a Proportional
Window of 2
˚
, if you are 2
˚
or more from setpoint, the amount of
signal change will be 10% per time period, and at 1
˚
from setpoint
the change would be 5% per time period. So, a larger proportional
window allows for
fi
ner tuning of the control signal to prevent
overshooting.
The Time Period is the length of time between Modulating Signal
adjustments. Short Time Periods may cause hunting of the Modu-
lating Signal.
Description
Minimum
Default
Maximum
Mod Heat Proportional
Window
.1ºF
(.1
º
C)
10ºF
(5.5
º
C)
30ºF
(16.6
º
C)
Mod Heat Time Period
5 sec
30 sec
240 sec
VCC-X Setpoint Screens
Setpoint Screen #24 - Mod Cool Proportional
Window and Time Period
VCC-X Spts ID:#
Mod Cool
Prop Window: 10.0
º
F
Time Period: 30s
The Modulating Cooling Proportional Window is the control range
of the Modulating Signal above and below the Active Supply Air
Temperature Setpoint. The size of the Proportional Window will
determine how much of a signal change the controller will make
per Time Period for every 1
˚
F the Supply Air Temperature is from
setpoint. The maximum signal change per time period is 10% when
the Supply Air Temperature is the full Proportional Window amount
from setpoint. So, with a 5
˚
Proportional Window, if the Supply Air
Temperature is 5
˚
or more from setpoint, the signal change will be
10% per time period. At 4
˚
difference, the signal change will be 8%
per time period. By the time the difference is 1
˚
, the signal change
will be 2% per time period. With a Proportional Window of 2
˚
, if
you are 2
˚
or more from setpoint, the amount of signal change will
be 10% per time period, and at 1
˚
from setpoint the change would
be 5% per time period. So, a larger proportional window allows for
fi
ner tuning of the control signal to prevent overshooting.
The Time Period is the length of time between Modulating Signal
adjustments. Short Time Periods may cause hunting of the Modu-
lating Signal.
Description
Minimum
Default
Maximum
Mod Cool Proportional
Window
.1ºF
(.1
º
C)
10ºF
(5.5
º
C)
30ºF
(16.6
º
C)
Mod Cool Time Period
5 sec
30 sec
240 sec
Setpoint Screen #25 - Head Pressure
Setpoints - Cooling and Reheat
VCC-X Spts ID:#
Head Pressure Spts
Cooling: 315psi
Reheat: 400psi
If a Head Pressure Transducer is connected to the RSM Module you
can control a Condenser Fan or a Condenser Water Valve to maintain
these Head Pressure Setpoints in the Cooling and Dehumidi
fi
cation
Reheat Modes.
Description
Minimum
Default
Maximum
Cooling Head Pressure
Setpoint
240 PSI
315 PSI
420 PSI
Reheat Head Pressure
Setpoint
240 PSI
400 PSI
420 PSI
