Instructions for use
SCU 835 / SEC 15
3.3
Operation modes
The sensor control unit
SCU 835
can be operated in auto-function or configuration mode.
3.3.1
Auto-function mode
In auto-function mode all parameter settings are made via the operating elements on the mainboard
MB SCI 835
of
the
SCU 835
. Sensors are matched to the two cable ports
I
and/or
II
for alarm and display (→ 7.2.5.1).
Note
This parametrisation corresponds to a response behaviour according to
EN 54-22
,
classes A1N
.
3.3.2
Configuration mode
In configuration mode the
SCU 835
is parametrized and put into operation via the graphical user interface
GUI
d-LISTconfig
(→ Operating manual
60T340
). The connected sensors can be numbered in any order and freely
grouped from a
maximum of 264
possible zones in up to
32
alarm zones. For each alarm zone, the alarm
threshold values and certain evaluation parameters are individually programmable.
Important note
Parametrisation of the device configuration may
only
be performed by trained personnel.
In configuration mode, it is also possible to operate the
SCU 835
as a slave unit in an
RS485
or
LAN
network with
the graphical user interface
GUI d-LISTconfig
, or to connect the device to a
FACP
and/or
PLC
via software pro-
tocol.
3.4
Programming
Note
The device can
only
be programmed and commissioned by trained personnel using the graphical user
interface
GUI d-LISTconfig
(→ Operating manual
60T340
).
Operation on a closed device is not possible. Should it be necessary due to maintenance work or malfunctions, the
unit can be opened by trained personnel and reset manually. Two possibilities are available for this purpose:
Press
RESET
button
→ to reset alarms and faults on site at the device.
Press
MC-RESTART
button
→ to restart the microcontroller.
Note
Operation of the
RLTHD
is usually carried out directly via the connected
FACP
. Alarms and faults can be
reset, sensors and alarm sections can be switched off/on and set to revision.
Important note
When operating the
SCU 835
during running operation, different information may be displayed depending
on the protocol. This can lead to a malfunction at the
FACP
.
3.5
Measuring cycles
The
SCU 835
operates independently for both cable connections
I
/
II
in intervals of
10 seconds
. A measuring cycle
consists of addressing each individual sensor, reading in the temperature values of the connected sensors and then
evaluating the transmitted temperature data in the microcontroller. The measuring cycle time for approx.
100
sensors per cable connection
I
and/or
II
is about five seconds. The two cable inputs are measured and evaluated in-
dependently at the same time.
Page 24/112
LISTEC GmbH
60T328-02-LI-en / 29.01.2021
