Mitsubishi Electric AT-50A, AT-50B Installation Manual

– 1 –

Chapter 1. Installation

Thoroughly read the following safety precautions prior to installation. Refer to Chapter 2. “Initial Setting” in this manual, and the Instruction Book for
information on operating or making the settings for the controller. Also, refer to the air conditioning unit installation manuals for how to connect cables or how
to install air conditioning units.

1-1. Safety Precautions

• Thoroughly read the following safety precautions prior to installation.

• Observe the following precautions to ensure safety.

• Nomenclature

• After reading this manual, pass it on to the end user to retain for future reference.

• Keep this manual for future reference and refer to it as necessary. This manual should be made available to those who repair or relocate the controller.
Make sure that the manual is passed on to any future AT-50A users.

WARNING

CAUTION

WARNING

CAUTION

WARNING

Indicates a risk of death or serious injury.

CAUTION

Indicates a risk of serious injury or structural damage.

(Prohibited actions) (Do not touch) (No water) (No wet hands) (Fire hazards) (Electric shock hazards) (Injury hazards) (Important actions) (Grounding required)

General precautions

Precautions during installation

Air-conditioner Control System

Advanced Touch Controller AT-50A

Installation Manual For distribution to dealers and contractors

WT06091X01

All electric work must be performed by qualified personnel.

Do not install the unit in a place where large amounts of oil, steam, organic
solvents, or corrosive gases, such as sulfuric gas, are present or where acidic/
alkaline solutions or sprays are used frequently. These substances can
compromise the performance of the unit or cause certain components of the
unit to corrode, which can result in electric shock, malfunctions, smoke, or fire.

To reduce the risk of shorting, current leakage, electric shock, malfunctions,
smoke, or fire, do not wash the controller with water or any other liquid.

To reduce the risk of electric shock, malfunctions, smoke or fire, do not operate
the switches/buttons or touch other electrical parts with wet hands.

T o reduce the risk of injury or electric sho ck, before sprayin g a chemical around
the controller, stop the operation and cover the controller.

To reduce the risk of injury or electric shock, stop the operation and switch off
the power supply before cleaning, maintaining, or inspecting the controller.

Properly install all required covers to keep moisture and dust out of the controller.
Dust accumulation and water can cause electric shock, smoke, or fire.

To reduce the risk of injury, keep children away while installing, inspecting, or
repairing the controller.

To reduce the risk of fire or explosion, do not place flammable materials or use
flammable sprays around the controller.

To reduce the risk of damage to the controller, do not directly spray insecticide
or other flammable sprays on the controller.

To reduce the risk of electric shock or malfunctions, do not touch the touch
panel, switches, or buttons with a pointy or sharp object.

To reduce the risk of injury and electric shock, avoid contact with sharp edges
of certain parts.

To avoid injury from broken glass, do not apply excessive force on the glass
parts.

To reduce the risk of injury, wear protective gear when working on the
controller.

Do not install the controller where there is a risk of leaking flammable gas.
If flammable gas accumulates around the controller, it may ignite and cause a
fire or explosion.

Properly dispose of the packing materials. Plastic bags pose suffocation hazard
to children.

Take appropriate safety measures against earthquakes to prevent the
controller from causing injury.

To prevent injury, install the controller on a flat surface strong enough to
support its weight.

To reduce the risk of shorting, current leakage, electric shock, malfunctions,
smoke, or fire, do not install the controller in a place exposed to water or in a
condensing environment.

Controller must be installed by qualified personnel according to the instructions
detailed in the Installation Manual.
Improper installation may result in electric shock or fire.

– 2 –

WARNING

CAUTION

WARNING CAUTION

1-2. The CD-ROM that is supplied with AT-50A

The CD-ROM that is supplied with AT-50A has Installation Manual and Instruction Book in English, German, French, Spanish, Italian,
Portuguese, and Russian.

Each document is in PDF format.
Viewing documents requires a computer with Adobe Reader or Adobe Acrobat installed.

“Adobe Reader” and “Adobe Acrobat” are registered trademarks of Adobe Systems Incorporated.

Precautions during wiring

Precautions for moving or repairing the controller

Additional precautions

WARNING

The CD-ROM that is supplied with the Remote Controller can only be played on a CD-drive or a DVD-drive.
Do not attempt to play this CD-ROM on an audio CD player as this may damage your ears and/or speakers.

To reduce the risk of damage to the controller, malfunctions, smoke, or fire, do
not connect the power cable to the signal terminal block.

Properly secure the cables in place and provide adequate slack in the cables
so as not to stress the terminals. Improperly connected cables may break,
overheat, and cause smoke or fire.

To reduce the risk of injury or electric shock, switch off the main power before
performing electrical work.

All electric work must be performed by a qualified electrician according to the
local regulations, standards, and the instructions detailed in the Installation
Manual. Capacity shortage to the power supply circuit or improper installation
may result in malfunction, electric shock, smoke, or fire.

To reduce the risk of electric shock, install a breaker and a residual current
circuit breaker on the power supply . To reduce the risk of electric shock, smoke,
or fire, install a breaker for each controller.

Use properly rated breakers and fuses (breaker, local switch <switch + fuse>,
no-fuse breaker). The use of a breaker with a breakin g capacity grea te r than th e
specified capacity may cause electric shock, malfunctions, smoke, or fire.

To reduce the risk of current leakage, overheating, smoke, or fire, use properly
rated cables with adequate current carrying capacity.

Proper grounding must be provided by a licensed electrician.
Do not connect the grounding wire to a gas pipe, water pipe, lightning rod, or
telephone wire. Improper grounding may result in electric shock, smoke, fire, or
malfunction due to electrical noise interference.

To reduce the risk of electric shock, shorting, or malfunctions, keep wire pieces
and sheath shavings out of the terminal block.

To reduce the risk of shorting, current leakage, electric shock, or malfunctions,
keep the cables out of contact with controller edges.

To reduce the risk of electric shock, malfunctions, or fire, seal the gap between

the cables and cable access holes with putty.
The controller should be repaired or moved only by qualified personnel. Do not
disassemble or modify the controller.
Improper installation or repair may cause injury, electric shock, or fire.

To reduce the risk of shorting, electric shock, fire, or malfunction, do not touch

the circuit board with tools or with your hands, and do not allow dust to

accumulate on the circuit board.

To avoid damage to the controller, use appropriate tools to install, inspect, or repair
the controller.

AT-50A is designed for exclusive use with the Building Management System by
Mitsubishi Electric. The use of this controller for with other systems or for other
purposes may cause malfunctions.

Take appropriate measures against electrical noise interference when installing the
air conditioners in hospitals or facilities with radio communication capabilities.
Inverter, high-frequency medical, or wireless communication equipment as well as
power generators may cause the air conditioning system to malfunction. Air
conditioning system may also adversely affect the operation of these types of
equipment by creating electrical noise.

To avoid malfunctions, do not bundle power cables and signal cables together, or
place them in the same metallic conduit.

To avoid damage to the controller, do not overtighten the screws.

To avoid discoloration, do not use benzene, thinner, or chemical rag to clean the

controller. To clean the controlle r, wipe with a soft cloth soaked in water with mild

detergent, wipe off the detergent with a wet cloth, and wipe off water with a dry cloth.

To avoid damage to the controller, provide protection against static electricity.

Do not use solderless terminals to connect cables to the terminal block.

Solderless terminals may come in contact with the circuit board and cause

malfunctions or damage the controller cover.

To avoid damage to the controller, do not make holes on the controller cover .

To avoid deformation and malfunction, do not install the remote controller in direct

sunlight or where the ambient temperature may exceed 40ºC (104ºF) or drop below

0ºC (32ºF).

– 3 –

1-3. Parts list

The package contains the following parts.

1-4. Product specifications

1. Specifications

*1 Not for use with a generic DC power supply device. Use the power supply unit for transmission line (PAC-SC51KUA etc.) by Mitsubishi.
*2 "Power consumption Coefficient" is a coefficient to calculate the relative power consumption of the devices that receive power through the M-NET

transmission line. Refer to the note at the end of section 1-5 "System diagram."

2. Unit Components and Functions

1-5. System diagram

1. System configuration

*1 ISO metric screw thread

Power source

30VDC *1
(for connection to M-NET only)

Receives power from the power supply unit for transmission line or
from outdoor units via the M-NET transmission cable. The power
consumption coefficient*2 of AT-50A is "4."

Operating conditions

Temperature

Operating temperature range 0˚C~40˚C [32˚F~104˚F]
Storage temperature range -20˚C~+70˚C [-4˚F~+158˚F]

Humidity 30%~90%RH (Non-condensing)
Weight 0.5 kg [1-1/8 lbs.]
External dimensions (W x H x D) 180 x 120 x 30 mm 7-3/32 x 4-23/32 x 1-3/16 in

Front (with the cover on) Front (cover off) Back Bottom

Parts Qty.

1. AT-50A 1

2. Mounting bracket 1

3. M4.1 wood screws × 16 *1 (Use to attach the mounting bracket to a wall.) 4

4. M4 Roundhead cross slot screws × 30 *1 (Use to attach the mounting bracket to an electric box.) 2

5. M4 roundhead screws with spring washers/washers × 20
(Use to attach the mounting bracket to th e controller.) *1

2

6. Installation Manual (This manual) 1

7. Instruction Book 1

8. CD-ROM (Instruction Book, Installation Manual) 1

2. Mounting bracket1. AT-50A

Power LED Touch panel

For connection to the M-NET
(A, B: Terminal for connection to
the M-NET cable [non-polarized])

External output
adapter cable
access hole

External input
adapter cable
access hole

Controller cover
mounting screw

SD memory slot
(for program updates)

TB7 TB3

ME

MA

MA

R2

TB7 TB3

MA MA

[051]

[001]

[106]

[006] [007] [008] [009]

[010]

[056]

[057]

[002] [003] [004] [005]

[11]

[12]

[13] [14]

M-NET

Main SC

Advanced Touch

Controller

*1

Model:

AT-50A [201]

Power supply unit for transmission cable
(sold separately)
Model: PAC-SC51KUA

Outdoor unit

M-NET

Group 1

M-NET
Outdoor unit

Group 2

Indoor unit
Local remote controller
M-NET transmission cable

MA remote controller c a b le

Numbers in the parentheses indicate address
numbers.

Note:

• The figure at left only shows the
transmission line connections.
Power supply lines are omitted.

• Provide a single ground point
(class D) by grounding the shield
wire of the M-NET centralized
controller transmission cable at
one of the power supply units.
Provide a ground point for the
indoor-outdoor transmission
cable for each outdoor unit.

• Make sure that the centralized
control switch (SW2-1) on the
outdoor unit connected to the M­NET cable is set to ON.
Refer to the outdoor unit
Installation Manual for detailed
information about dip switch
settings.

BC controller

Group 3

Group 6

Group 4 Group 5

M-NET
adapter

LOSSNAY

unit

Outdoor

unit

ON/OFF remote controller

Model: PAC-YT40ANR A

[202]

Mr. Slim

®

outdoor unit

Mr. Slim

®

outdoor unit

M-NET

Interface

MXZ

– 4 –

*1 The power consumption coefficient of AT-50A is 4 and that of an indoor unit is "1"*, which means that each AT -50A unit consumes power equivalent to

four indoor units. (*Indoor units receive power through the M-NET transmission line to maintain communication during power failure.) Refer to the
CITY MULTI DATABOOK for details. The total power consumption of the connected devices should not exceed the capacity of the power supply units.
The Design Tool by MITSUBISHI ELECTRIC allows its user to design air conditioning systems easily.
AT-50A is compatible with the Design Tool version 3.9 or later.
AT-50A can be connected to either TB7 or TB3.
When connected to TB3, no power supply units are required.

• Address settings (Address overlaps are not allowed.)

Note

2. M-NET wiring design
(1) M-NET transmission cable specifications and restrictions

Address setting Address range

Indoor unit

Assign the lowest address to the main indoor unit in the group, and assign sequential addresses to
the rest of the indoor units in the same group.
Note: The following models require two addresses: PEFY-AF1200CFM and PEFY-AF1200CFM-R

1~50

Outdoor unit

Assign an address that equals the lowest indoor unit address in the same refrigerant system plus

50.

51~100

Auxiliary outdoor unit
(BC controller)

Assign an address that equals the address of the outdoor unit in the same refrigerant system
plus 1.

52~100

LOSSNAY unit

Assign an arbitrary but unused address to each LOSSNAY unit after assigning an address to all
indoor units.

1~50

Mr. Slim

®

unit Same rules as for the indoor units apply. An M-NET adapter (sold separately) is required. 1~50

MXZ unit Same rules as for the indoor units apply. An M-NET interface (sold separately) is required. 1~50
M-NET remote controller

Assign an address that equals the address of the main indoor unit with the lowest address in the
group plus 100. Add 150 instead of 100 to set a sub-remote controller.

101~200
Sub system controller Assign an address that equals the lowest number of the group to be controlled plus 200. 201~250
DIDO

(PAC-YG66DCA)

Assign an arbitrary but unused address to the controller after completing the address setting for
the units with an address between 1 and 50. The number of controllable units depends on the
number of channels used. (1 channel = 1 unit)

1~50

MA remote controller

Address setting is not required. The connection of two remote controllers requires the main/sub
setting for each controller to be made.

–

Cable
Specifications

Facility type All facility types
Type

Shielded cable

CVVS · CPEVS · MVVS

No. of cores 2-core
Size

CVVS, MVVS: 1.25 mm² (AWG16) or larger

CPEVS: ø1.2 mm (AWG16 or its equivalent) or larger
Maximum indoor-outdoor transmission cable length 200 m [656 ft]
Maximum length of transmission line for centralized control and

indoor-outdoor transmission cables
(Maximum cable distance via outdoor unit)

500 m [1640 ft]

*The maximum cable distance from the power supply unit to each outdoor

unit or to the system controller is 200 m [656 ft].

• The system cannot be configured as shown in the examples below.
►Groups that are not controlled by a main controller cannot be

controlled from a sub controller.

►Sub controllers cannot be controlled by two or more main controllers.

►Each group cannot be controlled by two or more main

controllers.

Group Group Group Group Group Group

Group

Group Group Group

Main system controller 2Main system controller 1

Main system controller Sub system controller

Sub system controller

Main system controller 1 Main system controller 2

– 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 installationThin 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

edb

f

g

Power supply
unit for transmission
cable

Outdoor

unit

Indoor unit Indoor unit

Indoor unit

Indoor unitIndoor 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.