A52x Series Electronic Refrigeration Controller with Adaptive Defrost Technical Bulletin
15
Alarm Setup Parameters
Alarm Actions
•
Piezo: If enabled, the piezo energizes.
•
Alarm Relay: The alarm relay energizes when any alarm condition is TRUE. The alarm relay de-energizes
when you acknowledge the alarm locally or when the condition is no longer TRUE.
•
Local UI: The local UI lights the alarm icon when any alarm condition is TRUE or requires
acknowledgment.
Alarm Settings
You must set these parameters for each alarm:
•
Threshold: Each alarm may 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 or 0, or an Open or Closed selection to indicate the alarm state.
•
Piezo: Enabled or Disabled.
•
Delay: This time is represented in minutes. The alarm condition must remain TRUE for the required
number of minutes before an actual alarm sounds. 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. The latching alarm requires you to
acknowledge an alarm at the A52x Controller. The alarm icon remains lit, the alarm relay energizes, and
the piezo sounds (if enabled) 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 itself 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 set up 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. A lit yellow alarm
icon indicates an alarm warning. Alarm warnings do not cause the alarm relay to energize and the system does not
add an alarm to event log.
Cooling Shutdown
Cooling Shutdown is a specific action that can occur when one of the two Universal Input modes receives an
external signal. The controller turns off the compressor and the fan when the system receives an external signal.
Table 7: List of Alarms and Alarm True Conditions
Alarms
Alarm TRUE Condition
High Temperature Alarm
The Sensor 1 temperature is greater than the high temperature alarm value that you defined for a
period of time equal to or greater than the alarm delay.
Low Temperature Alarm
The Sensor 1 temperature is less than the low temperature alarm value that you defined for a
period of time equal to or greater than the alarm delay.
Sensor Failure
Sensor 1 is in a state of failure.
Sensor Failure
Sensor 2 is in a state of failure.
Door Open Alarm
The door is open for a period of time equal to or greater than the value that you defined.
Man in Room Alarm
A person is in the room for a period of time equal to or greater than the value that you defined.
Refrigerant Leak Alarm
The refrigerant leak detector indicates a leak. This may be a voltage level that you defined.
Emergency Shutdown
Emergency shutdown activates when a person trapped inside a cold room flips a switch.
