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4.5 TEMPERATURE CONTROL
4.5.1 Temperature Determination
The control system monitors the temperature readings
from the supply and return temperature sensors to
determine the mode of operation required to maintain
compartment temperature in accordance with the set-
point.
The sensor used for temperature control is dependent
on the selection made in the TEMP CONTROL Func-
tional Parameter.
• If the selection is RETURN AIR the return air
sensor (RAT) will be used, for any setpoint.
• If the selection is SUPPLY AIR the control sys-
tem will switch to the supply air sensor (SAT)
when operating with a perishable setpoint (refer
to Section 4.5.2 for more information on frozen
and perishable setpoints) and the return air sen-
sor will continue to be used for frozen setpoints.
4.5.2 Perishable And Frozen Setpoint Ranges
There are two ranges defined for setpoint.
a. Perishable Range = setpoints above +10.4°F (-
12°C).
b. Frozen Range = setpoints at or below +10.4°F (-
12°C).
4.6 START-STOP OPERATION
Start-Stop is provided to reduce fuel or power con-
sumption. This feature allows full automatic control of
the unit by monitoring compartment temperature, bat-
tery condition and engine coolant temperature.
The main function of Start-Stop Operation is to shutdown
the engine after certain conditions are met (to provide an
efficient temperature control system) and to initiate a
restart sequence after certain conditions are met. The
Start-Stop/Continuous key is pressed to select between
Continuous and Start-Stop Operation. The mode of oper-
ation will be indicated in the status bar.
NOTE
The control system may be locked so that
the unit will always operate in Start-Stop
whenever the setpoint is within a specific
range. Refer to Range Lock (Section
4.10.2) for additional information.
4.6.1 Start-Stop Configuration
Start-Stop Operation is dependent on both Configura-
tion and Functional Parameter settings. The first set-
ting to be considered is the START-STOP
PARAMETERS Configuration. This setting determines
control actions when in the Perishable Range or Fro-
zen Range. The available settings are TOGETHER
and SEPARATE.
• When SEPARATE is chosen the control action
will be different, depending on whether the set-
point is in the Perishable Range or in the Frozen
Range (refer to Section 4.5.2).
• When TOGETHER is chosen, the same settings
apply to any setpoint.
If TOGETHER is selected, then the following Func-
tional Parameter values will be available for use:
• MINIMUM RUN TIME
• MINIMUM OFF TIME
• RESTART TEMPERATURE
• OVERRIDE TEMP
• MAXIMUM OFF TIME
• FROZEN SHUTDOWN OFFSET
If SEPARATE is selected, then the following Functional
Parameter values will be available for use:
• PERISHABLE MINIMUM RUN TIME
• PERISHABLE MINIMUM OFF TIME
• PERISHABLE RESTART TEMPERATURE
• PERISHABLE OVERRIDE TEMP
• PERISHABLE MAXIMUM OFF TIME
• FROZEN MINIMUM RUN TIME
• FROZEN MINIMUM OFF TIME
• FROZEN RESTART TEMPERATURE
• FROZEN OVERRIDE TEMP
• FROZEN MAXIMUM OFF TIME
• FROZEN SHUTDOWN OFFSET
NOTE
In the event that this Configuration was set
to SEPARATE and the eleven Functional
Parameters for Perishable and Frozen have
been set and then the Configuration is
changed from SEPARATE to TOGETHER,
the values from the Perishable settings will
be the ones that will be used.
4.6.2 Stop Parameters
Whenever the unit starts in Start-Stop Operation, it will
remain in the Start-Stop ON cycle until all five of the fol-
lowing criteria have been satisfied:
1. It has run for the selected Minimum Run Time
The MINIMUM RUN TIME is selected in the control
system Functional Parameters. The purpose of this is
to force the unit to run long enough to completely circu-
late the air inside the compartment, and to ensure that
the product temperature is at setpoint. This value may
be set from 4 to 60 minutes in 1 minute intervals. The
factory default setting is 4 minutes.
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