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ENGLISH
ir33 +030220441 - rel. 2.0 - 01.05.2006
Warnings for the relative threshold:
The value of AL does not indicate the actual alarm temperature, but the maximum permissible deviation
from the set point; changing the set point automatically changes the low temperature alarm, while the
maximum deviation allowed (=AL ) remains fi xed.
Note: the low temperature alarm features automatic reset (this means that if the temperature returns
above the minimum value set, the alarm signal is cancelled automatically).
Warnings for using the continuous cycle
The low temperature alarm is also used in the continuous cycle (see the description of parameter cc’.
In fact, if the temperature falls to the alarm level, the continuous cycle is stopped automatically, even if
the selected time has not yet elapsed. This deactivation, however, does not involve an alarm signal.
Default: AL =0 => low temperature alarm disabled.
Note: for the control probe alarm, the low temperature alarm is reset and monitoring reinitialised.
AH: High temperature alarm
This is used to determine the activation threshold for the high temperature alarm.
Relative threshold for high temperature alarm = (set point) + (value of AH)
AH=0 => Alarm disabled;
Absolute threshold for high temperature alarm = value of AH.
AH=200 => Alarm disabled.
Important: if the threshold AH is selected as relative, the value for disabling the alarm is 0, while if
selected as absolute, the alarm disabling value is 200.
Warnings for the relative threshold:
• the value of AH does not indicate the alarm temperature, but the maximum permissible deviation from
the set point; consequently, changing the set point automatically changes the high temperature alarm,
while the maximum deviation allowed (=AH) remains fi xed.
Warnings:
• the high temperature alarm has automatic reset: this means that if the temperature returns above/be-
low the minimum value envisaged, the alarm signal is cancelled automatically
• in the event of a control probe alarm, the high temperature alarm is reset and monitoring reinitialised.
Default: AH=0 => high temperature alarm disabled.
Ad: Temperature alarm delay
Indicates after how many minutes the temperature alarm is signalled when the temperature threshold is
exceeded.
Warnings:
• Setting a delay for signalling the temperature alarm may help eliminate false alarms due to interference
on the probe signal or brief situations (for example, the door to the cold room opened for a short
period);
• no temperature alarms are generated during the defrost and continuous cycle procedures;
• the temperature alarm is delayed by the time d8 after the defrost and by the time c6 after the continuous
cycle. At the end of these two times, the temperature alarm, if detected, is signalled without waiting for
the time set for Ad. If d8 and c6 are set to zero, the temperature alarm is signalled after the time Ad;
• as already indicated by the default value for parameters AL and AH, the instruments are programmed
in the factory with the relevant thresholds, and the high and low temperature alarms are disabled. The
alarms, when enabled, activate the buzzer, if enabled, and show a code on the display: HI for the high
temperature and LO for the low temperature alarm.
The following conditions generate the temperature alarms:
• high temperature alarm: the temperature measured by the virtual control probe is above the threshold
set for parameter AH;
• low temperature alarm: the temperature measured by the virtual control probe is below the threshold
set for parameter AL.
Default: Ad=120 => 120 minute delay for the temperature alarms.
A4: Multifunction digital input confi guration
In the ir33 series, this parameter and the model of controller used defi ne the meaning of the multifunction
digital input. The possibilities are described below:
A4=0 Input not active: the multifunction digital input is not used and is the factory-specifi ed confi guration
for all versions.
A4=1 Immediate external alarm: the digital input can be connected to an external alarm that requires
immediate activation (for example, high pressure alarm or compressor thermal overload). Specifi cally,
the alarm is detected when the contact opens (normal operation with contact closed). The activation of
the alarm:
• shows the message on the display (IA);
• activates the buzzer, if enabled;
• activates the alarm relay, if selected;
• involves the following actions on the actuators:
- compressor: operates depending on the values assigned to parameter A6 (stop compressor from
external alarm).
- fans: continue to operate according to the fan parameters (F).
When stopping the compressor, the minimum ON time (c3) is ignored. When the alarm stops, the
defrost and the continuous cycle can be performed again, and the compressor returns to normal
operation.
Important warning: remember that in order to ensure the safety of the unit in the event of serious
alarms, all the electromechanical safety devices required to guarantee correct operation must be fi tted
on the unit.
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