Sensitron MULTISCAN 8+ - Page 14

MT4412E Rev.3 15/10/2019 Page 14 of 30
Detectors with 4-20mA output
Detectors with 4-20mA analogue output are either connected to the central unit, directly on the
main board or via one remote 8-input STG/IN8-S module. The module may be connected
remotely to the central unit. For connection, a detector with a 4-20mA analogue output requires a
3-conductor cable: 2 conductors for the power supply (usually from 12 to 28 Vdc - refer to the gas
detector technical manual) and one conductor for the 4-20mA signal. The generally
recommended cable is a shielded 3 x 0.75, which allows up to 100 meters between the gas
detector and STG/IN8-S input module
Detectors with 4-20 mA output directly connected to the central unit
Fig. 2.2.1 a) Connection of the 8 detectors of the central unit
Detectors with a 4-20 mA output connected to the ST.G/IN8-S module
The following diagram shows the connection of a gas detector with a 4-20 mA output to a
STG/IN8-S input module. During system start-up, make sure that each gas detector reaches a
minimum voltage of 12 Vdc.
Fig. 2.2.1 b) Connection of the 8 detectors of the ST.G/IN8-S module
+V
+V -V
-V
2
3
4
5
6
7
8
S - +
1
DETECTOR
-V
I8
I7
I6
I5
+V
-V
I4
I3
I2
I1
+V
-V
B
A
+V
REMOTE INPUT
MODULE ST/G.IN8
(+V)
(-V)
(S)
Positive
Negative
4-20 mA signal
4-20 mA
analog
gas
detector
Rilevatore
analogico
4-20 mA
MODULO INGR.
4-20 mA ST/G.IN8