Wiring Instructions; Maintenance - Yamatake HTY78 3 Series Specifications & Instructions

Wiring Instructions

Shielded multi-core cables (CVV-S) of 1.25 mm² or 2
mm² must be used. Be sure to ground the shielded
cable on the controller side.
If you don't need splash-proof, a 1.25 mm² or 2 mm² IV
cable may be used for power and a 1.25 mm² shielded
cable for humidity and temperature signals.
The maximum cable length is 100 m.
Never connect power supply to temperature output.
Always check wiring before supplying power.
Never share 24 V AC transformer to other products.
Use of individual AC transformer of humidity
transimitter
Use insulated transformer to supply 24 V AC
power supply voltage
Never share 24 V AC power supply with other
equipment.
If a transformer is shared with other equipment,
loop will be formed at common and the sen-
sor/transmitter may be damaged.
Transformer (24 V AC power supply) shared
•
Temperature / humidity sensor
24 V AC
〜 〜 〜 〜
⊥ ⊥ ⊥ ⊥
Temperature / humidity sensor
〜 〜 〜 〜
⊥ ⊥ ⊥ ⊥
Common loop formed
• Transformer (24 V AC) separated
Temperature / humidity sensor
24 V AC
〜 〜 〜 〜
⊥ ⊥ ⊥ ⊥
Temperature / humidity sensor
24 V AC
〜 〜 〜 〜
⊥ ⊥ ⊥ ⊥
No common loop formed
CAUTION
Multi-loop
controller
＋ ＋ ＋ ＋ ＋ ＋ ＋ ＋
− − − − − − − −
＋ ＋ ＋ ＋ ＋ ＋ ＋ ＋
− − − − − − − −
Not Good
Multi-loop
controller
＋ ＋ ＋ ＋
＋ ＋ ＋ ＋
− − − − − − − −
＋ ＋ ＋ ＋ ＋ ＋ ＋ ＋
− − − − − − − −
Good
24 V DC power shared
•
24 V DC
＋ ＋ ＋ ＋
− − − −
Follow the next instructions to prevent an induction cur-
rent flowing from the humidity sensor to the controller
input circuit, or to prevent an influence on the generating
noise due to inadequate time constant of the controller
input.
Use a controller with a low pass filter with a removal
•
ratio of 40dB or higher (normal mode).
Connect an isolator to the controller input circuit if a
•
removal ratio is unknown.
If you use a Yamatake controller, no problem will
•
occur.

Maintenance

Since the temperature / humidity sensor have been in-
spected and adjusted accurately before shipment, they
need no adjustment at the site. However, follow the
Common
share
maintenance instructions below:
1) Periodical inspection
Determine the periodical inspection intervals according
to the amount of suspended dust and other
contaminants in the environment. Regulary check the
sensor's accuracy and the condition of its cover.
2) Troubleshooting
If any problem occurs during operation, refer to the
following table for appropriate solutions.
7
Temperature / humidity sensor
〜 〜 〜 〜 ＋ ＋ ＋ ＋
⊥ ⊥ ⊥ ⊥ − − − −
Temperature / humidity sensor
〜 〜 〜 〜 ＋ ＋ ＋ ＋
⊥ ⊥ ⊥ ⊥ − − − −
Good
Common loop formed, however, not
so affected by common mode noise.
Multi-loop
controller
＋ ＋ ＋ ＋
− − − −
＋ ＋ ＋ ＋
− − − −
AB-5961