Azbil Neosensor Series - Page 17

AB-7050
17
Precautions for wiring
IMPORTANT:
• Do not connect the lead wires for temperature output to the power supply line to prevent smoking or burnout.
Make sure all the wires are correctly connected before supplying power.
• Single Neosensor must be powered by a single 24 V AC transformer. Do not connect the transformer to any
other device in addition to Neosensor.
● For power supply wiring and temperature/humidity output wiring, 1.25 mm
2
or greater shielded multi-core cables (JIS
CVV-S) are recommended. 1.25 mm
2
or greater JIS IV cable is also connectable. Be sure to ground the shielding on the
controller side.
The maximum cable length is 100 m.
● Because the temperature sensor model with RTD (Pt1000) output is two-wire, the wire resistance will cause measuring
error. For instance, 1.25 mm
2
size wire causes approx. 0.1 °C measuring error every 10 m. Correct the measuring error by
setting the controller in connection.
Transformer for Neosensor (humidity sensor, temperature/humidity sensor models)
IMPORTANT:
Use isolated transformer to supply 24 V AC power.
Single Neosensor must be powered by a single 24 V AC transformer. If the multiple Neosensor or a
Neosensor and a device in connection are powered by a single 24 V AC transformer, the common wiring will
form a loop, and Neosensor will get damaged.
24 V AC transformer: Two Neosensor powered by a single transformer
Figure 22. Bad wiring examples: Two Neosensor (temperature/humidity sensors) powered by a single 24 V AC transformer
24 V AC transformer: Two Neosensor separately powered by two transformers
Figure 23. Good wiring example: Two Neosensor (temperature/humidity sensors) powered by separate 24 V AC transformers
If the transformer is misconnected, it will short-circuit through the common wiring.
Bad wiring
Controller
Common
wiring
24 V AC
Temperature/
humidity sensor
+
-
+
∼
⊥
-
∼
+
-
+
-
⊥
Temperature/
humidity sensor
Bad wiring
Common wiring forms a loop.
24 V AC
Temperature/
humidity sensor
Temperature/
humidity sensor
Controller
+
-
+
∼
⊥
-
∼
+
-
+
-
⊥
Common
wiring
Common wiring does not form a loop.
Good wiring
24 V AC
Temperature/
humidity sensor
Controller
+
-
+
∼
⊥
-
∼
+
-
+
-
⊥
24 V AC
Temperature/
humidity sensor