Contact at P303
Signal
Cable colour
PE
Cable shield (insulate with heat shrinkable tubing)
[BK]
TX
Data transmission line (transmit)
[WH]
232-G
GND
[BN]
RX
Data transmission line (receive)
[GN]
+ 2-OUT
optional
output 2 (
+5 V … +32V DC, 500 mA
)
[WH]
- 2-OUT
optional
output 2 (
0 V
)
[BN]
+ 1-OUT
optional
output 1 (
+5 V … +32V DC, 500 mA
)
[WH]
- 1-OUT
optional
output 1 (
0 V
)
[BN]
Table 24: Pin assignment at
P303
Attention
In case of additional equipment, the voltage and current consumption of the devices to be connected
must
be taken into account in order
not
to damage the sensor control unit
SCU 835
during the control
process.
Note
For communication via
RS232
serial interface, the corresponding standard must be complied with.
6.7
Optocoupler inputs
External signals can be read in and processed via the
four
optional inputs at
P102
of the
SCU 835
. If required, sev-
eral alarm zones can be assigned to one input, which must be connected with
+24 V DC
from the connected equip-
ment (e.g.: external door contacts, push-button detectors etc., → 3.18).
The following options can be activated:
MaxOnly
Alarm zones can be assigned individually or several times to an input. External signals can be read in here,
which are exclusively used to ensure a temporary maximum temperature alarm evaluation, e.g. for external
door contacts, push-button detectors, etc.. The signals are connected with 24 V DC at the input.
Default:
not activated
.
Note
If an input is deactivated, a follow-up time in minutes has to be specified (
MaxOnlyDelay
). After the timer
has expired, the differential temperature alarm evaluation is fully functional again.
Attention
This function can slow down the alarm triggering in the event of a fire, as it only takes effect when the
maximum temperature threshold is exceeded and should only be used in special applications, e.g. cold
stores.
Extern Fault
The fault contacts of a connected 24 V power supply unit can also be linked to an input. Default:
not activ-
ated
.
60T328-02-LI-en / 29.01.2021
LISTEC GmbH
Page 55/112
Fig. 111: Circuit board cut-out for
MB SCI 835
terminal block → optocoupler outputs
