Setpoints Capacity Control - Johnson Controls FRICK QUANTUM LX Operation

090.022-O (MAY 12)
Page 30
ACCESSING:
DESCRIPTION: The Capacity Control Mode 1 -4 screens are identical in appearance (with the exception that Low Suc-
tion will only appear if Suction Pressure has not been selected as the controlling mode). All setpoints having to do with
Capacity Control, Autocycle, Mode Safeties and Low Suction are found here.
Capacity Control is setup by accessing the Confi guration
screen. From that screen, the user can enable or disable
any of the four possible modes, as well as select the chan-
nel that they wish to control from, and select whether the
control will be Forward or Reverse acting.
The Capacity Control screens shown above can display up
to four window areas of information:
• Capacity Control
• Autocycle
• Mode Safeties
• Low Suction
NOTE: If the Capacity Control mode is set to control
based upon suction pressure, then the Low Suction
window will appear blank, and the Mode Safeties
window values will act to protect the compressor for
Low Suction situations. If Capacity Control is not con-
trolled from Suction Pressure, then the Low Suction
window will be populated with values because the
Mode Safeties window will act to monitor the Ca-
pacity Channel, but Low Suction data must also be
monitored simultaneously.
The four widow areas are described as follows:
CAPACITY CONTROL - Capacity Control can be set to
act in either Forward or Reverse control. In Forward
control, as the value of the capacity control channel
increases the Quantum LX increases the capacity of
the compressor. In Reverse control, as the value of
the capacity control channel decreases the Quantum
LX increases the capacity of the compressor. The fol-
lowing setpoint boxes are provided:
Setpoint - This setpoint is used to control the
loading and unloading of the compressor when
QUANTUM™ LX COMPRESSOR CONTROL PANEL
OPERATION
SETPOINTS - Capacity Control
Setpoints...
Capacity...
Mode
the Capacity Control is in the AUTO (Automatic)
or in REM SEQ (Remote Sequencing) modes.
Proportional Band High - A band, measured in
the units of the Capacity Control setpoint, above
the Dead Band High, where proportional load or
unload control is used. If the actual reading rises
into this proportional band the load or unload
output will be pulsed as explained below in the
description about proportional band.
Proportional Band Low - A band, measured in
the units of the Capacity Control setpoint, below
the Dead Band Low, where proportional load or
unload control is used. If the actual reading falls
into this proportional band the load or unload
output will be pulsed as explained below in the
description about proportional band.
DESCRIPTION OF PROPORTIONAL BAND
CONTROL: The Proportional Band setpoint
determines a range of Capacity Control val-
ues where pulsed output control is used.
Outside of the proportional band the out-
put is continuously energized. The length
of time the output will be pulsed on is pro-
portional to the distance the actual reading
is from the Capacity Control setpoint. The
further the distance from setpoint, the lon-
ger the output is pulsed on and the shorter
the output is off. The closer the distance to
setpoint, the shorter the output is pulsed on
and the longer the output is off. If the actual
reading is midpoint from setpoint, the out-
put is on and off an equal amount of time.
Dead Band High - A band, measured in the units
of the Capacity Control setpoint, above the set-