Toshiba BMS-IFMB1280U-E Installation Manual page 9

Modbus interface
When the connected outdoor unit is Super Multi u series (U series)
Follow the wiring specifications in the table below even when there is a mix of U series and non-U series in the connected indoor
units or remote controllers.
Wiring specifications
Item
Wire diameter
Wire type
Wire types that can be used
REQUIREMENT REQUIREMENT
When wiring the control wiring between indoor and outdoor units (Uv line)/control wiring between outdoor units (Uc line) and
the central control wiring (Uh line), use the same wire type and diameter for each line.
Using a mixture of different wire types and diameters may cause a communication error.
System diagram
Central control
device
<U series>
Outdoor unit
(Super Multi
u series)
<U series>
Indoor unit *
<U series>
Remote
controller *
* The wiring specifications in the system diagram above are the same even when the indoor unit or remote controller are other
than the U series.
LINK (Uh)
U 3 U 4
U 3 U 4
U h
U c
U v U v
U 1 U 2 U 5 U 6 U 1
U 1 U 2 U 1 U 2
U4
U v U v
A B
U6
Communication line
Central control wiring (Uh line)
1.0 to 1.5 mm
2.0 mm
2-core, non-polar
Shielded wire
[Central control wiring (Uh line)]
L1 = Up to 2000 m
[Control wiring between indoor and outdoor units (Uv
line)/Control wiring between outdoor units (Uc line)]
L2 = Up to 1000 m
(L3+L4) = Up to 1000 m
U 3 U 4 U 3 U 4
U h U h
U c
U v
U 2 U 5 U 6 U 1 U 2 U 5 U 6
U 1 U 2
U4 U4
U v
A B A
U6
Installation Manual
2 (up to 1000 m)
(up to 2000 m)
2
U c
U 1 U 2
U4
U v
B A B
U6 U6
8-EN