3.6
Evaluation of the temperature values
Note
In the
SCU 835
, different evaluation algorithms can be set for different applications or application stan-
dards. Typical applications are e.g.:
1. according to
EN 54-22
as non-integrating resettable line type heat detector (factory setting), also suit-
able for
UL 521
.
2. according to
EN 54-22
as integrating resettable line type heat detector,
3. according to
GB 16280
as linear heat detector.
Non integrating linear heat detector according to
EN 54-22
and for
UL 521
:
The measuring cycle is carried out as described in point 3.5. After the measured value has been read in, a plausibil-
ity check is first performed. In case of discrepancies, the corresponding sensor is not considered for the current
measuring cycle.
Every valid measured value will be checked for two alarm criteria:
A maximum temperature alarm will be issued, if a sensor's actual temperature exceeds the maximum
temperature threshold. This threshold is defined at
+58 °C
(default setting for response classes
A1N
and
A2N
),
+70 °C
(for response class
BN
) resp.
+85 °C
( for response class
CN
). The pre-signal threshold
value can be set if required, standard
90 %
.
A differential temperature alarm will be issued, if a sensor's differential temperature exceeds the differen-
tial temperature threshold. This threshold is defined at
2.5 K
(default setting for response classes
A1N
,
BN
and
CN
). A limit value of
4.5 K
is specified for response class
A2N
.
The differential temperature of a sensor is calculated from the values of the currently measured temperat-
ure and the reference value of this sensor, taking into account a drift value with each measuring cycle. At
least
10
sensors per
SCU 835
are required for a correct differential temperature evaluation. The pre-signal
threshold value can be set if required, standard
50 %
.
3.7
Parameter sets
Following alarm thresholds and parameters are set when the unit is deployed according to
EN 54-22
:
Room protection application:
Response class A1N
(factory default)
Response class A2N
Differential temperature threshold:
2.5 K
4.5 K
Maximum temperature threshold:
58.0 °C
58.0 °C
Measuring cycle:
10 sec
10 sec
Reference tracking:
1
1
Table 8: Response classes A1N, A2N
Local protection application:
Response class BN
Response class CN
Differential temperature threshold:
2.5 K
2.5 K
Maximum temperature threshold:
70.0 °C
85.0 °C
Measuring cycle:
10 sec
10 sec
Reference tracking:
1
1
Table 9: Response classes BN, CN
Note
Changing any one parameter voids approval by VdS Schadenverhütung.
60T328-02-LI-en / 29.01.2021
LISTEC GmbH
Page 25/112
