Vaisala HMT370EX Guide D'installation page 21

4.3 Wiring with galvanic isolators
HAZARDOUS AREA
Test Points
V
mA
External
grounding
terminal
uses voltage input,
use a shunt resistor:
Figure 5 Wiring diagram with galvanic isolators
V
mA
galvanic isolators
4 ... 20
mA
4 ... 20
mA
If the controller
Chapter – Installation and wiring
SAFE AREA
DC power supply
Intrinsically
safe certified
L +
L -
+
+
-
-
L
+
L -
+
+
- -
Controller
4 ... 20 mA
+
U = I*RI
RI
-
+
-
Controller
+
-
+
-
17