Alarm Parameters; Haccp Alarm Parameters And Monitoring - Carel SmartCella 3PH User Manual

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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
A0 Alarm and fan diff erential
A1 Alarm thresholds (AL, AH) relative to set
point or absolute
0/1=relative/absolute
AL Low temperature alarm threshold
If A1= 0, AL=0: alarm disabled
If A1= 1, AL=-50: alarm disabled
AH High temperature alarm threshold
If A1= 0, AL=0: alarm disabled
If A1= 1, AL=200: alarm disabled
Ad High and low temperature alarm delay
A6 Stop compressor on external alarm
0 = compressor always off ;
100 = compressor always on
A7 Digital alarm input delay
0 = control outputs unchanged
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.
LO
ON
ALARM
OFF
A0
AL
Key
LO Low temperature alarm
HI High temperature alarm
"SmartCella manual" +0300084EN - rel. 1.2 - 28.03.2017
Def Min Max UOM
2.0 0.1 20.0 °C/°F
0 0 1
0 -50.0 200 °C/°F
0 -50.0 200 °C/°F
120 0 250 min
0 0 100 min
0 0 250 min
Tab. 8.a
HI
S1
A0
AH
Fig. 8.a
S1 Control probe
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
HAn Number of HA alarms
HA...HA2 HA HACCP alarms activated (press
-
Set)
y__ Alarm 1 to 3 - Year
M__ Alarm 1 to 3 - Month
d__ Alarm 1 to 3 – Day of the month
h__ Alarm 1 to 3 – Hour
n__ Alarm 1 to 3 – Minute
--- Alarm 1 to 3 – Duration
Htd HACCP alarm delay
0 = Monitoring disabled
AH
Sv
St
ON
ALARM
OFF
Key
S1 Virtual probe
St Set point
AH High temperature alarm
threshold
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
HFn Number of HF alarms
HF...HF2 HF HACCP alarms activated (press Set) -
y__ Alarm 1 to 3 - Year
M__ Alarm 1 to 3 - Month
d__ Alarm 1 to 3 – Day of the month
h__ Alarm 1 to 3 – Hour
n__ Alarm 1 to 3 – Minute
40
Def Min Max UOM
0 0 15 -
- - - -
0 0 99 year
0 1 12 month
0 1 31 day
0 0 23 hour
0 0 59 minute
0 0 240 hour
0 0 240 min
Tab. 8.b
t
t
Ad Htd
Fig. 8.b
Ad High and low temperature
alarm delay
Htd HACCP alarm delay
0 = monitoring disabled
t Time
Def Min Max UOM
0 0 15 -
- - -
0 0 99 year
0 1 12 month
0 1 31 day
0 0 23 hour
0 0 59 minute