ACI-Automation Components BACnet ROOM SERIES Installation Instructions

BACnet ROOM SERIES

Installation & Operation Instructions

GENERAL INFORMATION

The BACnet Room Series sensor is designed for use with
electronic controllers in commercial heating and cooling
building management systems. The ACI BACnet Room
Series sensor can be ordered to monitor temperature, RH,
or temp/RH in Commercial Room environments. It uses
BACnet MS/TP for physical connection to a BAS or
controller, has dip switches to set addresses and baud
rate, and has on board end-of-line termination. There is no
analog output.

WIRING INSTRUCTIONS

The BACnet Room Series temperature sensor has a
depluggable terminal block located on the backside of
the PCB. 16 to 22 AWG two conductor shielded cable is
recommended for powering the sensors.

PRECAUTIONS

• Do NOT run the wiring in any conduit with line

voltage (24/120/230 VAC).

FIGURE 1: LAYOUT

FRONT VIEW

LED

8421421

643216

BACK VIEW

BAUDADDRESS

RESET BUTTON

END OF LINE
TERMINATION

EN DIS

• Remove power before wiring. NEVER connect or

disconnect wiring with power applied.

• It is recommended that you use an isolated

UL-listed Class 2 transformer when powering the
unit with 24 VAC. Failure to wire the devices with the
correct polarity when sharing transformers may
result in damage to any device powered by the
shared transformer.

• If the 24 VDC or 24VAC power is shared with devices
that have coils such as relays, solenoids, or other
inductors, each coil must have an MOV, DC/AC
Transorb, Transient Voltage Suppressor (ACI Part:

142583), or diode placed across the coil or inductor.
The cathode, or banded side of the DC Transorb or
diode, connects to the positive side of the power
supply. Without these snubbers, coils produce very
large voltage spikes when de-energizing that can
cause malfunction or destruction of electronic
circuits.

D+ D- GN V

TERMINAL
BLOCKS
(LOCATED
ON BACK)

BACNET PWR

TABLE 1: WIRING CONNECTIONS

TERMINAL
BLOCKS

+V
GN
D­D+

CONNECTIONS

Power Supply Positive 12-36 VDC / 24VAC
Power Supply Common or Ground
EIA-485 Data Negative
EIA-485 Data Positive

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MOUNTING INSTRUCTIONS

ACI recommends using BELDEN 3105 for communication
wiring. This wire has 120 ohm input impendence. The
terminal blocks allow for (1) or (2) wires to be connected
in each position for daisy chaining. Daisy chain the RS-485
wiring and do not use “Star” or “T” wiring.

Avoid running communication wires next to AC line
voltage wires. These can be sources of noise that can
aect signal quality.

For optimal readings, follow these tips:

• Do not install on external walls

• Avoid air registers, diusers, vents, and windows

• Avoid conned areas such as shelves, closed

cabinets, closets, and behind curtains

• Eliminate and seal all wall and conduit penetrations.

Air migration from wall cavities may alter temperature
readings.

• Do not install near heat sources. eg: lamps,

radiators, direct sunlight, copiers, chimney walls,
walls concealing hot-water pipes

• A thermally-insulated backing should be used

when tting to solid walls (concrete, steel, etc.).
ACI part: A/ROOM-FOAM-PAD. Be sure to cut out
an area for slotting the detachable terminal block.

Separate the cover from the base. Attach the base directly
to the wall or to a standard 2” x 4” junction box using the
(2) #6-32 x 1” screws provided.

FIGURE 2: ENCLOSURE DIMENSIONS

1.12"

(28.36 mm)

2.75"

(69.85 mm)

4.50"

(114.30 mm)

FRONT

DETACHABLE
TERMINAL BLOCK

BOTTOM

(5.05 mm)

FIGURE 3: MOUNTING DIAGRAM

DETACHABLE
TERMINAL BLOCK

MOUNTING SCREW

(#6-32 x 1”)

CIRCUIT BOARD

COVER

OPTIONAL
INSULATING GASKET

BACKPLATE

48” - 60”

(1.2 - 1.5 m)

0.20"

Refer to the wiring instructions (p. 1-2) to make necessary
connections. After wiring, attach the cover to the base by
snapping the top of the cover on rst and then the
bottom. Tighten the cover down, using the (2) 1/16” Allen screws located in the bottom of the housing. A 1/16” Hex driver is
needed to secure the cover to the base.

Take care when mounting. Check local code for mounting height requirements. Typical mounting heights are 48-60” (1.2-1.5 m) o
the ground and at least 1.5’ (0.5 m) from the adjacent wall. The sensor should be mounted in an area where air circulation is well mixed
and not blocked by obstructions.

*Reference FIGURE 2 and 3

BACnet MS/TP INTERFACE

The BACnet Master-Slave/Token-Passing (MS/TP) data link protocol uses EIA-485 as a two-wire, daisy chain network. A branch is

a discrete chain of devices connected to a controller.

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