plug-in
Cod. +030221881 rel. 1.5 - 26/10/10
46
8.3.7 Parameters corresponding to the recording of the HA and HF alarms
left
segment
code parameter description min max uom def
tu da
of last HA even
1 7 - -
th hours of last HA even
0 23 hours -
t’ minutes of last HA even
0 59 min -
tA number of HA events de
ected
since reset
0 127 - 0
tt maximum tem
erature value durin
HA alar
-50 127
C/F
-50
td maximum duration of the HA events
0 18 hours 0
tu da
of last HF even
1 7 - -
th hours of last HF even
0 23 hours -
t’ minutes of last HF even
0 59 min -
tF number of HF events detected
since reset
0 127 - 0
tt maximum tem
erature value for HF alarm u
on resum
tion of
ower
-50 127
C/F
-50
tt maximum tem
erature value for HF alarm before
ower failure
0 127 - 0
td maximum duration of the HF even
0 18 hours 0
Tab. 8.3.6.1
The parameters for recording the status provide a detailed description of the HA and HF alarms which have occurred since the last
reset. All the parameters are display-only, they are divided into two distinct groups for HA alarms and HF alarms, and are
displayed only if the relative alarm HA or HF is effectively present. The parameters are identified using the name associated to a
segment of the left-most digit, for the HA alarms and for the HF alarms (see figure). The order of display of the parameters
is listed in the table.
In the case of more than one event saved, the recording is of the time of the last event only, the total number of HA or HF events,
the maximum temperature measured during the HA and HF alarms and of the relative maximum durations.
8.3.8 Operating mode and alarm signals
When the detection of the alarms has been enabled by the correct setting of parameters AH and tr, the HACCP module performs
continuous control, at one minute intervals, of the control temperature, and based on this and the other parameters (alarm threshold
and delay times) signals and records the type HA alarms, which regard the exceeding of the set temperature limits for extended
periods longer than the set delay times. The module also controls the temperature on re-starts after power failures, signalling and
recording type HF alarms.
HA alarm: arises when the control temperature is above the maximum set (SET+AH) for longer than the set delay (Ad + tr).
The parameter Ad sets the alarm delay of the plug-in instrument, on exceeding this time an alarm signal (high temperature) is
activated, generated by the instrument itself; this signal can be used as a pre-alarm for the subsequent signal that the total time has
been exceeded (Ad + tr), which determines the actual HA alarm. The two parameters allow a maximum duration of 326 minutes to
be set.
Any alarm event involving the control probe of the plug-in instrument (E0) is considered equivalent to the temperature being
greater than the threshold, and thus also determines a HA alarm signal after the set delay time.
When the HA alarm is detected the following information, regarding the status parameters, is recorded:
maximum temperature reached during the alarm (above SET+AH);
time the alarm event started;
duration of the alarm; when the alarm is in progress, the current duration is measured;
number of events (HA) detected.
In the case of a series of alarm events, the information on the alarm is updated:
the temperature involves the highest value of all the events recorded;
the time refers to the last event;
the duration is the longest of all the events recorded;
the number of events is increased by 1.
HF alarm: Occurs when, after a power failure for an extended period (more than one minute), the control temperature upon
resumption of power is above the set maximum (SET+AH).
The detection if this alarm is enabled as for the HA alarm: AH > 0 and tr > 0. The delay times in this case are not considered, as
the detection of the alarm is instantaneous if the power failure lasts longer than Ad, and Ad + tr also gives the HA alarm signal.
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