4
Figure 1: Electrical connections, transmitter connected to an
ISC/OLDHAM central unit.
The
-
(OUT) terminal of
j5
is at the same potential as the
V
-
power supply terminals of j1 (line A) and
j2
(line B).
+ -
S
E S E
IN 1 IN 2
4 -------- 20 mA
OUT
NO NF C
NO NF C
NO NF C
def
rel 1
rel 2
V+ / V- = sensor power supply
+ of j5 = signal output to
central measurement unit
The contact positions correspond to "sensor de-energerised"
(volt free relay)
fault relay
Alarm 1 relay
Alarm 2 relay
j1
0
V
+ -
V
-
V
+
RS485
Line A
j2
0
V
+ -
V
-
V
+
RS485
Line B
j5
IN 1
and
IN 2
analogue inputs
(4 …. 20 mA)
RS485 link
(
to next sensor in loop
)
OUT
: 4 … 20 mA analogue output
(
to measurement unit
)
RS485
: Digital signal
(
to measurement unit
)
Power supply to
next sensor
