Hitachi RAS-2HVNP Installations- Und Betriebshandbuch Seite 34

1 Electrical wiring
16
16.3.3 H-LINK system
The H-LINK system can not be applied to the cycle with the old
model unit or the unit with old transmission
1 Application
The new H-LINK wiring system requires only two transmission
wires connecting each indoor unit and outdoor unit for up to 16
refrigerant cycles, and connecting wires for all indoor units and all
outdoor units in series.
2 Features
The total wiring length is remarkably reduced.
-
Only one connection is required for the wiring between the
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indoor unit and outdoor unit.
Easy wiring connection to the central controllers.
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3 Specifications
Transmission Wire: 2-Wire
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Polarity of transmission wire: Non-polar wire
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Maximum outdoor units to be connected: 16 units per
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H-LINK system.
Maximum indoor units to be connected: 3 units per cycle
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and 48 units per H-LINK system
Maximum wiring length: Total 1000m (including CSNET
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WEB). In case that the total wiring length is longer than
1000m, contact the Hitachi dealer.
Recommended cable: Twist pair cable with shield, over
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0.75mm (Equivalent to KPEV-S)
2
Voltage: DC5V
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4 Example of H-LINK system
Using H-Link system only for air conditioners.
There are two typical cases of using H-LINK system:
a. Using H-LINK system only for air conditioners, without
control device.
Examples:
• Line connection with all units
Outdoor
units
Indoor
units
34
Do not make
wiring in a
PMML0248A
• Line connection for each floor
b. Using H-LINK system for air conditioners with central con-
trol device.
In case that H-LINK is not applied when electrical wiring is per-
formed.
N O T E
• Do not make a wiring in a loop.
• In the case that H-LINK is not applied after the when electri-
cal wiring is performed as shown above, H-LINK is applied
after the instrument wiring is completed. Therefore, the dip
switches are required to be set according to setting of Dip
switches on PCB.
5 Dip Switch Setting of Indoor PCB and Outdoor PCB
It is required to set dip switches of every indoor unit and outdoor
unit.
loop
Outdoor
units
Indoor
units
Outdoor
units
Indoor units