Table 24: Controller alarm parameters and descriptions
Alarm
parameter
Description
Threshold
Each alarm can have a specific level, units, and range. For example, temperature
alarms expect Fahrenheit or Celsius values to set the alarm threshold. The door
open alarm expects a time duration. A binary input expects a 1, 0, or an open or
closed selection to indicate the alarm state.
Delay
This time is represented in minutes. The alarm condition must remain true for the
required number of minutes before the alarm activates. If the condition clears
before the number of minutes elapses, no alarm action initiates. If you set the
delay to zero, the alarm triggers immediately.
Auto clear
Select a latching alarm or a self-clearing alarm. You must acknowledge the
latching alarm on the controller. The alarm icon remains lit and the alarm relay
energizes if you enable it on the device, until you acknowledge the alarm, even
if the alarm condition is no longer true. A self-clearing alarm is an alarm that no
longer identifies as true if the underlying alarm condition clears.
Re-alarm
interval
This time is represented in minutes. If you acknowledge the alarm and the alarm
relay deactivates but the alarm condition persists for this number of minutes, the
alarm relay reactivates.
Alarm vs warnings
The alarm setup includes a delay parameter. When an alarm condition crosses the alarm threshold,
the alarm does not occur until after the delay period. The alarm warning condition is active in this
situation. The
Alarm
icon glows yellow to indicate an alarm warning. Alarm warnings do not cause
the alarm relay to energize and the system does not add an alarm to the event log.
Cooling shutdown
If you set the action of a binary input mode to
COO-OFF
on the binary input setup screens, cooling
shutdown can occur when the binary input receives an external signal. The controller turns off the
compressor when the system receives an external signal. The controller sets the evaporator fan to
on or off depending on the value you set for the
EVAP FAN: COMPRESSOR OFF
parameter on the
refrigeration setup screens. See
Setting up the refrigeration setup parameters
for instructions.
System shutdown
A system shutdown takes priority over the normal control of the compressor, defrost, and
evaporator fan or auxiliary relays. A system shutdown can occur if an alarm condition such as a
refrigerant leak activates. During a system shutdown, all outputs are set to off with the exception
of the alarm output. The controller can enter a system shutdown state by detection of a refrigerant
leak, if enabled, or by the configuration of a binary input to provide this signal.
Info field codes
Codes flash in the two information fields in the lower-right corner of the LCD on the parameter
selection screens. The following table describes these codes.
Use the up and down arrows to move through the available selections on the screen. When the
preferred code is flashing in the info field, press
SET
to save the selection and to go to the next
screen.
MR5 Series Panel Mount Case Controller Technical Bulletin
54
Discontinued
