Carrier BN Series User manual

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Specification
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 1of 10
Overview
The BN Series Temperature and Humidity Duct networked sensors are a cost
effective, single or dual point native BACnet™ or Modbus sensing solution
designed to reduce the need for additional input modules or building management
controllers when a limited number of input points are available. The BN series
offers both BACnet™ and Modbus protocols in one device, providing great
flexibility with various systems. The BTL Certification provides confidence that
these sensors may be used in any new or retrofit installation using a BACnet™
MS/TP controller with third party BACnet™ devices. These sensors incorporate a
conformally coated printed circuit board mounted inside a waterproof enclosure for
long-term reliability. The enclosure features a twist off cover for easy access to the
wiring and internal dip switches for quick setup and installation.
Applications: Monitoring Supply / Discharge / Return Temperature and humidity,
Dehumidification and Humidification Processes, Clean Rooms, Data Centers,
Return Air in Pool Environments, Economizer Control, Air Handlers, Roof Top Units, Process Control Applications
The BN Series BACnet™ sensors are covered by a Two (2) Year Limited Warranty.
Part Numbers
N2-BN2110-D-4-PB-C
Specifications
Supply Voltage:
12 to 36 VDC / 24 VAC +/- 10%, 50/60 Hz (Reverse Polarity Protected)
Current Consumption:
25 mA maximum (0.67 VA)
Temperature Measurement Range:
-40 to 176ºF (-40 to 80ºC)
Temperature Measurement Accuracy @ 77ºF
(25ºC):
+/- 1.0ºF (+/- 0.5ºC)
Temperature Calibration Offset:
+/- 9ºF (+/- 5ºC) (Field Configurable)
Temperature Units:
ºF (Factory Default), ºC, ºK (Field Configurable)
RH Measurement Range:
RH Measurement Accuracy @ 77ºF
(25ºC): RH Calibration Offset:
0 to 100%
+/- 2% from 10 to 90% RH
+/- 10% RH (Field Configurable)
Resolution:
+/- 0.1º | +/- 0.1%
Temperature / RH Update Rate:
4 seconds
Communication Protocol:
BACnet™ MS/TP or Modbus RTU = Field Selectable; EIA RS-485
Sensor Addresses:
0 = Factory Default | 1-127 = Field Selectable
Supported Baud Rates:
Auto Baud (Factory Default) | 9600, 19200, 38400, 57600, 76800, 115200 (Field
Selectable)
Parity (Modbus RTU):
None/Even/Odd = Field Selectable
Stop Bits (Modbus RTU):
1 or 2= Field Selectable
Databits (Modbus RTU):
8
Maximum Distance:
4000 ft (1219 m)
End of Line Termination Resistance:
120 Ohms Termination Resistance (Field Selectable)
Tri-Color Status LED:
Connection Status
Connections | Wire Size:
Screw Terminal Blocks | 16 AWG (1.31 mm2) to 22 AWG (0.33 mm2)
Transmitter Operating Temperature Range:
-40 to 176ºF (-40 to 80ºC)

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Specification
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 2of 10
Storage Temperature Range:
-40 to 185ºF (-40 to 85ºC)
Operating Humidity Range:
10 to 95% RH, non-condensing
Sensing Probe and Filter Material | Probe
Diameter:
304 Stainless Steel | 0.750” (19.05 mm)
Enclosure Material | UL Flammability Rating:
ABS Plastic | UL94-HB
Enclosure Temperature Rating:
-40 to 140ºF (-40 to 60ºC)
Foam Pad Material | Flammability Rating:
Neoprene/EPDM/SBR Polymer | UL94-HBF; FMVSS-302; MIL-R-6130C
Product Dimensions (Length x Diameter):
10.06” (255.53 mm) x 4.30” (109.22 mm)
Product Weights:
1.30 lbs. (0.59 kg)
Agency Approvals:
BTL Certified, CE, RoHS2, WEEE, China RoHS
Dimensional Drawing
Figure 1: Dimensional Drawing

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 3of 10
Mounting Instructions
Tip
•The sensor should be mounted in the middle of the duct where air circulation is well mixed (no
stratification), and not blocked by obstructions. Stratification and obstructions can cause sensing
errors. An example is downstream from a heating or cooling coil.
•Duct probe should be placed (3) to (4) duct segments down from any bend or obstructions and
away from 90° bends.
•Mount the sensor on the top or sides of duct work; mounting on the bottom risks damage due to
moisture.
The BACnet/Modbus RTU Duct Temperature-only sensor uses the Plastic
Box (-PB) enclosure. Alternatively, the Euro (-EH) enclosure is used for
the Relative Humidity (RH) sensor and RH/Temperature Combo sensor
(see FIGURE 1). Be sure to follow the instructions listed for your
enclosure.
PLASTIC BOX (-PB) ENCLOSURE INSTALLATION
1. Drill a 3/8” hole in the duct and insert the probe through the hole until
the foam pad is tight to the duct.
2. Drill pilot holes for the (2) mounting screws. Use the enclosure flange
as a guide, or use the dimensions listed on page 1 to measure out.
3. Now fasten and insert (2) screws #8 x ¾” TEK (provided and
recommended) through the mounting holes in the flange and tighten
until the unit is held firmly to the duct.
4. Refer to the wiring instructions to make necessary connections.
5. After wiring, shut the cover of the enclosure.
Figure 2: Enclosure Dimensions

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 4of 10
Wiring Instructions
Warning
•Remove power before wiring. Never connect or disconnect wiring with power applied.
•DO NOT RUN THE WIRING IN ANY CONDUIT WITH LINE VOLTAGE (24/120/230 VAC).
Caution
•It is recommended 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, 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.
The BACnet/Modbus Duct Series temperature sensor has a
depluggable terminal block located on the front of the PCB. For ease
of wiring, we recommend removing the block, wiring, and reattaching
before mounting. 16 to 22 AWG two conductor shielded cable is
recommended for powering the sensors.
Carrier® recommends using Belden 3105 or compatible cable for RS-
485 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 affect
signal quality.
Figure 3: Layout

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 5of 10
EURO (-EH) ENCLOSURE INSTALLATION
1. Drill a 7/8” hole in the duct and insert the probe through the
hole until the foam pad is tight to the duct.
2. Drill pilot holes for the (2) mounting screws. Use the
enclosure flange as a guide, or use the dimensions listed to
measure out.
3. Now fasten and insert (2) screws #8 x ¾” TEK (provided and
recommended) through the mounting holes in the flange and
tighten until the unit is held firmly to the duct.
4. Refer to the wiring instructions to make necessary
connections.
5. After wiring, twist the cover until the enclosure is tightly
sealed.
BACnet MS/TP and Modbus RTU INTERFACE
The BACnet Master-Slave/Token-Passing (MS/TP) and Modbus Remote Terminal Unit (RTU) 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. The max number
of devices per segment is 32, as per the BACnet and Modbus specifications. 4000 ft (1219.2 m) is the maximum
recommended length for a segment, which includes all devices from the controller to the last device in the daisy chain.
BACnet or Modbus RTU protocol selection is done via SW4 switch.
Place dipswitch #4 to the OFF position for BACnet and the ON position
for Modbus.
Carrier®’s BACnet sensors are master devices. Only master nodes are
allowed to send and receive tokens on the MSTP network.
Carrier®’s Modbus RTU sensors are slave devices. Only one master is
connected to the bus and several slave nodes are connected to the
same trunk. The Master initiates communication. The slave nodes only
respond to a request from the Master. Slave nodes do not
communicate with each other.
Each branch must have all devices connected with (+) connected to (+)
and (-) connected to (-). If a shielded cable is used, this is not to be connected to the devices. The shield cable should only
be connected on one end to earth ground, usually at the controller. The start and end of each branch should have a
termination resistor at the device level or at the controller.
Each device must be configured for the correct baud rate and have a unique address in each branch. The baud rate for the
branch is set by the controller. This product has auto-baud for ease of network configuration but setting the baud rate
using the DIP switches is recommended.
NOTE Auto-baud feature does not function when Modbus is the selected protocol.
Figure 4: SW4 Dipswitch Setting

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 6of 10
BAUD RATE SELECTION
By default, BACnet Protocol and Auto-Baud is factory set. If
the sensor is field adjusted for Modbus RTU, the baud rate
should be selected at this time to match the Master
configuration. If Modbus RTU protocol is selected it is
recommended the sensor unique address is selected at this
time. Switches 8-10 are used to set the BACnet and Modbus
baud rate. Refer to switch settings. Where (0) is OFF and (1) is
ON. If the system’s baud rate is known, it is recommended to
set the specific baud rate to match the system. If the device is
powered when a change is made, the device must be power
cycled or reset for changes in baud rate to be made.
EOL TERMINATION RESISTANCE SELECTION
RS-485 requires that the last device in a chain have a termination
resistor. This is controlled using a jumper in the EN (enabled) position
marked on FIGURE 5. When the jumper is set to EN (enabled), a 1200
resistance is added in parallel to the data line. When the jumper is set
to DIS (disable), the resistance is not added. By default, the jumper is
placed in the DIS (disabled) position.
RESET
The reset button can be used to reset the device without disconnecting power. The location of this button is shown in
Figure 3.
LED INFORMATION
One LED indicates four statuses. Solid green shows that power is good, but no data is transmitting. A solid Amber
indicates that auto-baud is set and no data has been received to set a baud rate. Green/Amber flashing indicates data is
being transmitted or received. Solid Red LED status indicates an error state, usually loss of communication on the
network. If BACnet is the selected protocol, and this status remains for 10 times the APDU timeout, the device will
automatically reset. If this state remains longer than that, reset the device.
ADDRESS SELECTION
Switches 1-7 are used to set the BACnet and Modbus addressing.
Refer to switch settings. Each device in a network branch must
have a unique address. The value of each position is printed on the
board. By default, the address is
(0). Note: (0) cannot be used if Modbus RTU protocol is selected
and will require a unique address. If the device is powered when a
change is made, the device must be power cycled or reset for
changes in address to be made.
Figure 5: EOL Termination Jumpers

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 7of 10
DEVICE CONFIGURATION THROUGH BACnet
DEVICE INSTANCE
The Device Instance, by default, is 1035000 plus the Address. For example, an Address of 21 results in a default address
of 1035021. This can be changed once the device is connected to the network, but each device instance must be unique
within the network, not just this segment.
DEVICE NAME
By default, the device name is based on the type of device and the address. The device
name can be a character string up to (32) characters in length. This can be changed once
the device is connected to the network. For example: Temperature Sensor - 034. The
device name must be unique throughout the entire BACnet network, not just this segment.
TEST MODE BACnet
For the Sensor objects (AI0 and AI1), a test mode can be set by writing the Boolean value true to the “out-of-service”
property. Then the present-value can be set to any valid test value the user requires. This allows a user to test reactions to
specific values returned by this device.
DEVICE LOCATION
The device location is optional but is intended to allow for further definition of the device’s location. The device location can
be a character string up to 64 characters in length.
DEVICE DESCRIPTION
By default, the device description is optional but is intended to allow for further information about the device or its
environment. The device location can be a character string up to 64 characters in length.
TEMPERATURE UNITS CONFIGURATION
For temperature, the units of measure can be configured using BACnet. By writing to the units property of the temperature
sensor (AI0), the reported temperature units can be changed.
TEMPERATURE AND RH OFFSET
This device allows for a temperature offset of +/-5C (9F) and an RH offset of +/-10%. By default, these values are set to 0,
meaning no offset is added.
These are set by writing to the present value of the Temperature Calibration Offset (AV0) or RH Calibration Offset (AV1).
The value written must be within the specified range or an error will be returned. To set back to factory settings, write any
changed values to 0.

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 8of 10
BACnet Object Table
NOTE The table shows all objects for Temperature and RH. If you have a Temperature only model, the RH objects(AI-1
and AV-1) will not be present. If you have a RH only model, the Temperature objects (AI-0 and AV-0) will not be present.
DEVICE CONFIGURATION THROUGH MODBUS RTU
MODBUS RTU DATA BITS, PARITY, AND STOP BITS SELECTION
Confirm Modbus Protocol is selected via dipswitch #4 on SW4 -
see FIGURE 4. The device that requests information is called the
Modbus Master and the devices giving the information are Modbus
Slaves. The Modbus sensors are slave devices and the number of
Data Bits needs to be the same as in the Master device
configuration. Modbus RTU sensors utilize 8 data bits during
communication exchange.
Parity and stop bit selection is performed via the SW4 switch located on the board. Dipswitches #1 and #2 are adjusted to
select the parity and stop bits. Where (0) is OFF and (1) is ON. If BACnet protocol is selected these dipswitches are
irrelevant.
TEST MODE Modbus RTU
There are 5 data values in test mode. Coil 1001, Holding Registers (HR) 1001 and 1002, and the Input Registers (IR) 0003
and 0004 for Temp and RH values. When Coil 1001 is enabled, reading IR 0003 and 0004 will respond with the values in
HR 1001 and 1002, other wise they will respond with the actual sensor values. General process for this is to write initial
test values to HR 1001 and 1002, Enable Coil 1001 and then read as normal from IR 0003 and 0004. While Coil 1001 is
enabled, it is possible to write a change of value to IR 1001 and 1002, which will be reflected in the next read from IR 0003
and 0004. When testing completed, disable Coil 1001. The status of Coil 1001 and HR 1001 and 1002 are not persistent
between reset/power cycle.
MODBUS RTU MODEL
Four (4) primary data tables (addressable registers)
•Discrete Input (read only bit).
•Coil (read / write bit).
•Input register (read only 16-bit word, interpretation is up to application).
•Holding register (read / write 16-bit word).

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 9of 10
MODBUS RTU MAP
REFERENCE
ADDRESS
NAME
DESCRIPTION
COILS (CL)
1001 1000 Test Mode Enable 0 = Disable Test Mode. IR3 and IR4 will read with current Sensor
Value.
1 = Enable Test Mode. IR3 and IR4 will read with the values stored in
HR1001 and HR1002 .
INPUT REGISTER (IR)
1 0 Sensors Present
For each bit
location:
0 = Sensor not present
1 = Sensor present
Bit 0 - Temperature Sensor Bit 1 - RH sensor
2
1
Reserved
N/A
3
2
Temperature Sensor
Value
For example, a value of 312 would represent 31.2 Degrees of the units
selected in HR1. Signed Integer.
4 3 RH Sensor Value For Example: A value of 429 would represent 42.9% Relative
Humidity.
INPUT REGISTER (IR)
2001
2000
Temperature Range
Min
Temperature range Minimum value (Tenths). Signed Integer.
2002
2001
Temperature Range
Max
Temperature range Maximum value (Tenths). Signed Integer.
2003
2002
RH Range Min
Relative Humidity range Minimum value (Tenths)
2004
2003
RH Range Max
Relative Humidity range Maximum value (Tenths)
9001
9000
Unsigned Integer
Test Value
Always reads a value of 54321. For testing proper communication and
interpretation of values.
9002
9001 Signed Integer Test
Always reads a value of -12345. For testing proper communication and
interpretation of values.
9003 Thru
9006
9002 Thru
9005
Test String Test Value
Always reads a string value of "-123.45" (Null terminated). For
testing
proper communication and interpretation of values.
9007 Thru
9010
9006 Thru
9009
Serial Number
Non-null terminated character string of the Serial Number. For
example, "12345678”
9011 Thru
9016
9010 Thru
9015
Firmware Version
Non-null terminated character string of the Firmware Version. For
example, "02.00.000.90"
HOLDING REGISTER (HR)
1
0
Temperature Units
Value - Units:
62 - Degrees Celsius
63 - Degrees Kelvin
64 - Degrees Fahrenheit
2
1
Temperature Offset
Value
Temperature Offset Value (Tenths) Signed Integer.
User can set an offset that will be added to Temperature sensor and
reflected in IR3. Range of -5.0 to 5.0 degrees Celsius/degrees Kelvin (-
9.0 to 9.0 degrees Fahrenheit).
For example, writing -16 would add an offset of -1.6 degrees.
3
2
RH Offset Value
Relative Humidity Offset (Tenths)
User can set an offset that will be added to RH sensor and reflected in
IR4. Range of -10.0 to 10.0 %RH.
For example, writing -16 would add an offset of -1.6 %RH.
1001
1000
Test Mode
Temperature Value
User can set what temperature value (Tenths) that would be returned
when reading IR3 and Test Mode is Enabled in CL1001. For Example -
400 would be -40.0.
1002
1001
Test Mode RH Value
User can set what RH value (Tenths) that would be returned when
reading IR4 and Test Mode is Enabled in CL1001.

Duct RH-Temperature BACnet MSTP Modbus RTU Sensor
Installation and
Operation
#N2-BN2110-D-4-PB-C – 8/31/23
Specifications subject to change without notice.
Catalog No. 11-808-994-01 Page 10 of 10
9001 Thru
9016
9000 Thru
9015
Device Name
Device Name, Device Location, and Device Description are user settable
character strings (Null terminated) that can be used to allow
for system
customization and device identification.
For example:
Device Name (Modbus 9001 thru 9016) could be set to a system ID:
"S2253"
Device Location (Modbus 9017 thru 9048) could be set to: "Building 5,
Floor 2, Duct 3"
Device Description (Modbus 9049 thru 9080) could be set to: "Cold air
return sensor"
9017 Thru
9048
9016 Thru
9047
Device Location
9049 Thru
9080
9048 Thru
9079
Device Description
Appendix – Symbols Key
Warning Potential for death, serious injury, or permanent damage to a system.
Caution Potential for injury, damage to a system, or system failure.
Tip Useful information not related to injury or system damage.
W.E.E.E. DIRECTIVE
At the end of their useful life the packaging and product should be disposed of via a suitable recycling center. Do not
dispose of with household waste. Do not burn.