CONTROL OPERATION
Temperature Control
Control Value Averaging
The system requires one temperature and humidity
sensor (included with LV) to operate. It allows a
total
of three temperatures and three humidity sensors to
be connected to the LV for better representation of
what is happening in the shelter. When more than one
sensor is used, the value is averaged and then used for
temperature control operations and humidity control
operations.
Comfort Mode
The LV has a feature that allows a temporary override
of the temperature control settings. When “comfort
mode” is activated, the system will control to 72°F.
The system will stay in this mode for 60 minutes
and is intended to provide a more comfortable space
for a technician during a service call or scheduled
maintenance.
Emergency Mode
When the high temperature alarm 2 or the hydrogen
input indicate an alarm, the system will enter
emergency mode. The LV will communicate to each
wall unit that emergency mode is active. The wall units
will the override the damper position to 100% open
and turn the blower on. These two items will stay in
this state until both the high temperature alarm 2 and
the hydrogen detector are no longer in an alarm state.
Cooling
When the wall units are connected to the LV, the
economizer and compressor are commanded off and
on by the LV. This allows the supervisory controller to
consider the most effective and efficient order to bring
cooling functions on using all of the available equipment
installed on the shelter. At the same time the LV will be
able match the load requirements of the shelter.
To adjust the cooling setpoint:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
USER password 2000.
3. Press UP or DOWN keys to scroll to
Sys Config
;
press ENTER key.
4. Press UP or DOWN keys to scroll to
Unit Setup
(A1)
; press ENTER key.
5. Press ENTER key to scroll to
Cooling
(see Figure
2.6).
6. Press UP or DOWN keys to adjust value.
7. Press ENTER key to save.
8. Press the ESCAPE key several times to return to
Main Menu screen.
FIGURE 2.6
Adjusting Setpoints
The LV monitors the space temperature and compares
the value to the space cooling setpoint. The system will
compare how far above or below the space temperature
is when compared to the cooling setpoint. The LV will
also consider how long the shelter temperature has
been above or below the setpoint. Using these two
considerations, the controller will generate a cooling
demand. The cooling demand is a value between 0 and
100%. 0% represents no cooling demand and 100%
representing full cooling demand.
The system will consider all of the available cooling
stages and distribute the number of stages across
the cooling demand range. As the demand rises, the
system will stage on equipment every 2 minutes. As the
demand lowers, the system will stage off equipment
every 2 minutes.
The system will stage the equipment on in the order
shown in Table 2.2.
The system is also capable of rotating the order
in which the units are brought on. This is done to
distribute the equipment run time to each unit. This
prevents one unit from providing all of the cooling for
the shelter and shorting the lifespan of the wall unit.
The system is set to switch the unit staging order
every 7 days from the factory. This timeframe can be
changed if desired by the end user. In addition to the
time-based auto rotation, the system can be manually
rotated on site for troubleshooting purposes.
To view the lead unit, turn the rotation on/off, change
the number of days between rotations or manually
rotate the units:
1. Press MENU key to go to the Main Menu screen.
2. Press UP or DOWN keys and ENTER key to enter
USER password 2000.
3. Press UP or DOWN keys to scroll to
Sys Config
;
press ENTER key.
4. Press UP or DOWN keys to scroll to
Unit Rotation
(A2)
; press ENTER key.
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