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The panel controls the backlight current based on the
equipment room ambient temperature.
Menus
The display has access to the current operation status,
specific machine data, machine setup, service, and
diagnostic messages. Details of these menus are discussed
later in this section
Alarm LED.
1) The single red LED (located to the right of the display)
will BLINK whenever a machine manual reset (MMR)
diagnostic exists and manual machine reset is required to
restore operation. This light is also lit when a manual
service function is set to manual.
2) The alarm LED will illuminate continuously when a
service test item is placed into manual mode operation. The
LED serves as a reminder that something remains in
manual mode. Manual mode operation of any service tests
(password protected) item must be terminated before the
machine is allowed to operate unattended in the auto
mode.
Operator Interface (LCLD) Operation
Keypad
Figure 6 illustrates the operator interface keypad. The
keypad is a sealed membrane type with 16 keys arranged 4
by 4. The keys are separated into three fields:
1) Report keys are located across the top row and are used
for viewing of preformatted information.
2) The second rows of keys are settings group menus.
These menus can have security passwords at operator and
service levels.
3) Functional keys are located across the bottom two rows
and are used to input changes.
The functional keys are discussed next since the operation
determines how the user communicates with the report
and settings menus.
Functional Keys
The
Next
and
Previous
keys allow the operator to step
through the various menus within a group. The report
group will sequence around to the top or bottom of that
group when the end or beginning is reached, respectively.
The
(+)
and
(-)
keys cause the displayed values to increase
or decrease, respectively. If the
(+)
or
(-)
key is held down
for more than 1/2 second it will increment or decrement the
setting continuously at 10 counts per second, until the key
is released. (Settings do not wrap around when the end of
range is reached). Once the
(+)
or
(-)
key has been pressed
to select a particular setting, the
Enter
key or
Cancel key
must be pressed. (The
Next
or
Previous
keys will not
advance until
Enter
or Cancel is pressed). A Setting is not
changed until the
Enter
key is pressed. The
Cancel
key is
pressed if a changed setting should not be saved. When the
Enter
key is pressed the display will blank out momentarily
to indicate to the operator that the keystroke was
recognized.
If the boundaries of a specific selection are exceeded the
operator interface will display out of range and will not
allow that selection to be entered.
When
Auto
is pressed the chiller will enter an auto mode of
operation.
When
Stop
is pressed the chiller will stop, entering the
“Unit is Preparing to Shutdown” mode.
During the five-second period a message indicating the
optional emergency stop command will be displayed.
The
Stop
key is located in the lower right hand corner.
WARNING
I
f the Stop key is pressed a second time within five
seconds an immediate “Panic Stop” will be executed,
overriding the normal “Unit is Preparing to Shutdown”
mode.