3.11
Fault signalling
Fault signalling will take place as:
Visually by the alarm
LED
s
I
/
II
on the front panel .
Electrically via common fault relay per cable connection
I
/
II
.
Electrically via up to
16
section alarm relays (optionally via relay board
REL 835
).
Informally via data interface and software protocol (optional).
Attention
Faults are
not
reset automatically.
Faults can
only
be reset, if the reason for the fault has been cleared.
3.12
Indicators on the front panel
Various operating states are displayed on the front panel of the
SCU 835
. A direct operation at the closed instrument
is not possible (→ 7).
3.13
Operating voltage
The
SCU 835
must be supplied with an operating voltage from
+10,5 to +34 V DC
. If the voltage falls below the min-
imum voltage by
15 %
, the controller outputs a mains undervoltage fault (→ 6.2).
The operating voltage is derived via DC/DC converters on the mainboard to other internal voltages:
+5 V DC
for sensor cable
SEC 15
.
+3,3 V DC
for microcontroller.
+15 V DC
for Weak-Pullup sensor cable.
The following voltages are relevant for the following optional modules:
Relay board
REL 835
→
+5 V DC
from mainboard
MB SCI 835,
internally with
+3,3 V DC
.
e
X
tended
L
ine
M
odule
XLM 35
→
+5 V DC
from mainboard
MB SCI 835
.
M
ulti
L
ine-
S
pecial
F
ire
D
etector
ML-SFD
→ operating voltage
+10.5 … +30 V DC
.
3.14
Sensor cable connections
Two cable connections
I
/
II
are available on the sensor control unit
SCU 835
,
P201
and
P202
. The connected
sensor elements
SEC 15
are measured and evaluated independently of each other at both cable inputs. This is in-
dicated visually on the front panel by two blue measuring cycle
LED
s
. The device can also be operated with one
sensor cable connection, it does not matter to which cable port the sensor element is connected (→ 6.3). An unused
cable port
must
be deactivated via the configuration wizard of the graphical user interface
GUI d-LISTconfig
.
3.15
External reset
The
SCU 835
is designed in such a way that direct operation at the front panel is not possible. Normally, all alarms
and faults must be acknowledged and reset via the connected
FACP
. An external reset input
P401
on the main-
board
MB SCI 835
is available for this purpose (→ 6.4).
3.16
Relay outputs
On the mainboard
MB SCI 835
there are common fault- and alarm relays on
P304
and
P305
per cable port
I
/
II
(→ 6.5). Optionally, a relay board
REL 835
can be installed, with a maximum of
16
relays for alarm, pre signal or
malfunction per fire zone (→ 6.12).
Note
All relay contacts of the
SCU 835
and the relay board
REL 835
are potential-free.
60T328-02-LI-en / 29.01.2021
LISTEC GmbH
Page 27/112
