– 5 –
The figure below shows the M-NET transmission wiring diagram for City Multi air conditioners.
The maximum length of centralized control M-NET transmission line and the indoor-outdoor transmission line per system can be expressed in
the following formulas. Labels "a through g" represent the sections of wiring in the system in the figure below. These limits ensure normal signal
communication over the M-NET transmission line.
If the line length exceeds the maximum length, M-NET signal attenuation can occur, rendering normal communication and control impossible.
a+b+d+e(f)
≤
500 m (1640 ft)
a+b+c+g
≤
500 m (1640 ft)
e(f)+d+c+g
≤
500 m (1640 ft)
The maximum length of local remote controller cable is 10 m (32 ft). The length that exceeds 10 m (32 ft) must be included in the maximum total
line length 500 m (1640 ft).
1-6. Installation
1. Field-supplied parts
The following parts are required to install the controller.
2. Required tools
• A knife or nippers • Crosshead driver
3. Installation methods
Follow the instructions provided for the selected installation option.
(a) Wall-embedded installation using an electric box
(b) Wall-surface installation
(b-1) To route the cable through the wall
(b-2) To route the cable along the wall surface
4. Preparation
(1) Install a breaker on the power supply unit side before installing the controller.
(2) Select an installation site for the AT-50A.
• Install the controller at the user's eye level for easy operation.
• Ensure there is enough clearance space as shown in the figure at right.
• Ensure there is enough clearance space to allow for easy access to the panel and the
buttons.
(3) Bring the cable end up to the controller.
Ensure the M-NET transmission cables and external input/output cables are long enough to reach
the controller. Have extra cables to extend these cables as necessary.
• To install the controller according to the instructions provided in sections (a) and (b-1) above
Include an extra 30 cm (12 in) of cable to provide adequate slack in the cable.
Remove the sheath on the M-NET transmission cable up to 20 cm (8 in) from the end.
• To install the controller according to the instructions provided in section (b-2) above
Include an extra 15 cm (6 in) of cable to provide adequate slack in the cable.
Remove the sheath on the M-NET transmission cable up to 10 cm (4 in) from the end.
(4) Prepare the AT-50A.
Unscrew the screw at the bottom of the controller, and
remove the cover.
To route the cable along the wall surface, cut out the
rectangle knockout hole (18 mm (W) x 9 mm (D)) at
the top of the controller with a knife or a nipper (shown
as the shaded area in the figure below at right).
Parts
Qty.
Note
Triple electric box
1
Not required for wall-surface installation
Thin metal conduit
As appropriate
Lock nut and bushing
As appropriate
M-NET cable
As appropriate
Shielded cable
CVVS, MVVS: 1.25 mm²~2 mm² (AWG16~14)
CPEVS: ø1.2 mm~ø1.6 mm (AWG16~14 or their equivalents)
a c
e
d
b
f
g
Power supply
unit for transmission
cable
Outdoor
unit
Indoor unit
Indoor unit
Indoor unit
Indoor unit
Indoor unit
Outdoor
unit
System
controller
Centralized controller
transmission line
M-NET
remote
controller
10 m (32 ft)
Indoor-outdoor
transmission line
30
(1.3/16)
30 (1.3/16)
50 (2)
30
(1.3/16)
Unit: mm (in)
AT-50A outline
Note
Note
Refer to section 1-7 "Using external
input/output" for how to connect
external input/output signal cables.
Do not push the shield wire into or
connect it to the AT-50A. Trim the
shield wire, cover it with vinyl
insulating tape, and leave it
outside the controller.
