User manual - METER PDU-4x0-W
a)
b)
Figure 4.16. Connections of 2-wire sensor:
a) active, b) passive (needs additional supply)
meter has no galvanic separation between measurement input and
RS-485 interface. If serial connection of multiple units is made or serial connection
with other device, without galvanic separation of RS-485 interface, is made then
RS-485 interface separators must to be used certainly (
If RS-485 interfaces are isolated or not used then the separators are not necessary.
Figure 4.17. Serial connection of active 2-wire sensor with
unit
and other current measurement device (e.g. PLC controller).
14
12 11
+
-
Current source
0 - 20mA or
4 - 20mA
12 11 10 9 8 7
+
-
Connected internally
!
-
+
Current source
0 - 20mA or
4 - 20mA
12 11 10 9 8 7
Connected internally
G
galvanic
isolation
+
-
A
B
+
-
R
B
