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44
ENG
ir0300028EN rel. 1.1 - 05.05.2017
8.5 Alarm parameters
Alarm parameters and activation
AAL (AH) is used to determine the activation threshold for the low (high)
temperature alarm LO (HI). The value set for AL (AH) is continuously
compared against the value measured by the control probe. Parameter
Ad represents the alarm activation delay, in minutes; the low temperature
alarm (LO) is activated only if the temperature remains below the value
of AL for a time greater than Ad. The alarm may relative or absolute,
depending on the value of parameter A1. In the former case (A1=0),
the value of AL indicates the deviation from the set point and thus the
activation point for the low temperature alarm is: set point - AL. If the
set point changes, the activation point also changes automatically. In the
latter case (A1=1), the value of AL indicates the low temperature alarm
threshold. The low temperature alarm active is signalled by the buzzer
and LO shown on the display. The same applies to the high temperature
alarm (HI), with AH instead of AL.
Par Description Def Min Max UOM
A0 Alarm and fan diff erential 2.0 0.1 20.0 °C/°F
A1 Alarm thresholds (AL, AH) relative to set
point or absolute
0/1=relative/absolute 0 0 1 -
AL Low temperature alarm threshold
If A1= 0, AL=0: alarm disabled
If A1= 1, AL=-50: alarm disabled 0 -50.0 200 °C/°F
AH High temperature alarm threshold
If A1= 0, AL=0: alarm disabled
If A1= 1, AL=200: alarm disabled 0 -50.0 200 °C/°F
Ad High and low temperature alarm delay 120 0 250 min
A6 Stop compressor on external alarm
0 = compressor always off ;
100 = compressor always on 0 0 100 min
A7 Digital alarm input delay
0 = control outputs unchanged 0 0 250 min
Tab. 8.a
Note:
•
alarms LO and HI have automatic reset. A0 represents the hysteresis
between the alarm activation value and deactivation value;
•
if Prg/mute is pressed when the value measured is above one of the
thresholds, the buzzer is immediately muted, while the alarm code
and the alarm output, if set, remain active until the value measured
is outside of the activation threshold. For delayed alarms from digital
input (A4=2, code dA), the contact must remain open for a time greater
than A7. In the case of an alarm event, a counter starts and generates
an alarm when reaching the minimum time A7. If during the count
the value measured returns within the threshold or the contact closes,
the alarm is not signalled and the count is reset. When a new alarm
condition occurs, the count starts from 0 again. Parameter A6 has a
similar meaning to parameter c4 (duty setting). If an external alarm
occurs (immediate or delayed) the compressor works for a time equal
to the value set for A6 and remains off for a fi xed time of 15 minutes.
OFF
AL
S1
A0
LO HI
A0
AH
ON
ALARM
Fig. 8.a
Key
LO Low temperature alarm S1 Control probe
HI High temperature alarm
8.6 HACCP alarm parameters and
monitoring
HA alarms
The alarm queue can be displayed by accessing parameters HA to
HA2. The type HA alarm is generated if during normal operation the
temperature read by the control probe exceeds the high temperature
threshold for the time Ad+Htd. Consequently, compared to the normal
high temperature alarm already signalled by the controller, the type HA
HACCP alarm is delayed by a further time Htd specifi cally for HACCP
recording. The order of alarms listed is progressive, HA is the most recent
alarm. A maximum of 3 errors are saved, in a FIFO list (HA to HA2): FIFO
(First In First Out) management means the fi rst error recorded is the fi rst
to be cancelled when the list is full and needs to be updated. The last
error saved is displayed for parameter HA. HAn indicates the number of
type HA alarms activated.
Par. Description Def Min Max UOM
HAn Number of HA alarms 0 0 15 -
HA…HA2 HA HACCP alarms activated (press
Set)
- - - -
y__ Alarm 1 to 3 - Year 0 0 99 year
M__ Alarm 1 to 3 - Month 0 1 12 month
d__ Alarm 1 to 3 – Day of the month 0 1 31 day
h__ Alarm 1 to 3 – Hour 0 0 23 hour
n__ Alarm 1 to 3 – Minute 0 0 59 minute
--- Alarm 1 to 3 – Duration 0 0 240 hour
Htd HACCP alarm delay
0 = Monitoring disabled 0 0 240 min
Tab. 8.b
ON
OFF
ALARM
St
AH
Ad Htd
Sv
t
t
Fig. 8.b
Key
S1 Virtual probe Ad High and low temperature
alarm delay
St Set point Htd HACCP alarm delay
0 = monitoring disabled
AH High temperature alarm
threshold t Time
ALARM HA HACCP alarm
HF alarms
The type HF HACCP alarm is generated following a power failure for an
extended time (> 1 minute), if when power returns the temperature read
by the control probe exceeds the AH high temperature threshold. HFn
indicates the number of type HF alarms activated.
Par. Description Def Min Max UOM
HFn Number of HF alarms 0 0 15 -
HF…HF2 HF HACCP alarms activated (press Set) - - - -
y__ Alarm 1 to 3 - Year 0 0 99 year
M__ Alarm 1 to 3 - Month 0 1 12 month
d__ Alarm 1 to 3 – Day of the month 0 1 31 day
h__ Alarm 1 to 3 – Hour 0 0 23 hour
n__ Alarm 1 to 3 – Minute 0 0 59 minute