Honeywell C7355B User manual

USER GUIDE
31-00438-01
C7355B In-Duct IAQ Monitor
INTRODUCTION
About This Monitor
This air quality monitor is specially designed for
monitoring multiple air quality parameters in the air duct.
The sensor is installed in the outdoor or return air duct.
Real time monitoring parameters are particles (PM2.5 and
PM10), carbon dioxide (CO2), TVOC, air temperature and
relative humidity.
The intelligent control algorithms built into the device
help to minimize the influence of ambient temperature
and humidity on the measured values. The device is
packaged with numerous presets suitable for most
commercial building requirements that enable quick and
easy initial setup.
The device, with pitot tube inlet and outlet design instead
of common air pump, adapts to a wider range of air speeds
and insures a long lifetime of usage. It provides Modbus
RTU (RS-485) communication protocol, easily integrating
with the building automation system.
Intended audience and assumed
knowledge
This document provides information about installing and
commissioning the IAQ monitor. It also shows how to
operate the user interface.
It is assumed that the user is trained and familiar with
HVAC concepts.
IMPORTANT
Always install equipment in accordance with the
National Electric Code and in a manner acceptable
to the local authority having jurisdiction (AHJ). No
guidelines, instructions, installation practices, or
other information presented in this guide may be
interpreted to supersede or modify the local codes
and practices of the AHJ.
Reference documents
• In-Duct IAQ Monitor Specification Data 31-00439:
Describes in-duct IAQ monitor and its features.
• In-Duct IAQ Monitor Mounting Instructions 31-00440:
Describes how to mount the monitor.
• In-Duct IAQ Monitor Quick Start Guide 31-00441:
Contains only necessary procedures to enable the
users to quickly use the device.
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C7355B IN-DUCT IAQ MONITOR
31-00438—01 2
DIMENSIONS AND MOUNTING HOLES
Fig. 1. Dimensions
SPECIFICATIONS
Part Number:
C7355B1052
Detection Parameters:
PM2.5/PM10, CO2, TVOC, Temperature & RH
Operating Environment:
-4 to 140°F (-20°C to 60°C)
0 to 99% RH, (No condensation)
Storage Condition:
32 to 122°F (0°C to 50°C)
10 to 60% RH
Overall Dimension:
See Fig. 1
Net weight:
1.87lb (850g)
Certification Standard:
CE/FCC

C7355B IN-DUCT IAQ MONITOR
331-00438—01
IN-DUCT IAQ MONITOR AT A
GLANCE
Monitor Overview
The image below illustrates the typical enclosure of the
IAQ monitor. There is a pitot tube, main unit sensor
compartment and main unit communication control
compartment, as well as an external temp & humidity
sensors.
Fig. 2. Monitor Overview
Light Indication
The bottom right side of the device is the indicator area.
For this monitor (Part number: C7355B1052), only refer to
the ON and SCALE indicators.
Fig. 3. Location of light indicators
POWER SUPPLY AND RS-485
WIRING
WARNING
• To reduce the risk of electrical shock do not
disassemble the detector. There are no user
serviceable parts inside. Refer servicing to
qualified service personnel only.
• Use a dry cloth to clean the product. Do not use
liquid cleaners or aerosol cleaners
• Do not use the product near water. Do not install
the product in a place where water may splash
onto it.
• Do not operate the detector with a hard, sharp or
pointed object.
IMPORTANT
All wiring must comply with local electrical codes
and ordinances. Follow equipment manufacturer
wiring instructions when available. Power must not
be connected while wiring. Wiring a unit that is
powered may result in electrical shock and/or
equipment damage.
Main unit sensor
ensure air
ghtness,avoid affecng
the measurement accuracy
Temp & humidity sensor
Main unit
communicaon
control
The pitot tube
Table 1. Light Indication
Display LED status and Description
Work indicator
When the power is on, it will illuminate to indicate
the device is working. Otherwise, the device is
faulty.
- Three-color concentration indicator.
- The default is the average concentration change
of PM2.5 every 1 minute.
When PM2.5 <35 μg/m3green light on.
35 to 75 μg/m3yellow light on.
>75 μg/m3red light on
At t he same time, t h e measurement value of the
indicator change can be selected in the
communication command to be 1-minute
average.

C7355B IN-DUCT IAQ MONITOR
31-00438—01 4
Wiring Diagram
Fig. 4. Wiring Diagram
There are two sets of terminals, power supply wiring on the
left, RS-485 wiring on the right.
1. Remove the cover of the electrical wiring compart-
ment on the main unit.
Fig. 5.
2. Remove the two terminal blocks for power supply
and RS-485 respectively.
Fig. 6.
NOTE: The left terminal is the power terminal block. The
right terminal is the RS-485 terminal block.
3. Run the power cable and RS-485 cable through each
waterproof connector as shown in Fig. 7.
Fig. 7.

C7355B IN-DUCT IAQ MONITOR
531-00438—01
4. Connect the cable to the terminal blocks.
Fig. 8.
5. Plug the terminal block back onto the pin connector
and tighten the waterproof connectors.
Fig. 9.
6. Replace the cover of the electrical wiring compart-
ment and tighten the screws.
Fig. 10.
RS-485 CONFIGURATION
Prerequisites
Before going through RS-485 configuration, ensure the
monitor is installed and wired up according to the
Mounting Instructions.
After installing the monitor and powering it up for initial
use or re-use, the device should be energized
continuously for more than 48 hours to ensure stable
output of all measured values.
Modbus Register Table
Mode: RTU (MSB First)
Baud Rate: 1-4800 2-9600 3-14400 4-19200 5-38400
6-56000 7-57600 8-115200
default: 2-9600bps
Start Bits: 1
Data Bits: 8
Stop Bits: 1 / 2
default: 1
Parity: None / Odd / Even
default: None
Register Map
Support Function code:
3 - Read Holding Registers
4 - Read Input Registers
6 - Write Single Register
16 - Write Multiple registers

C7355B IN-DUCT IAQ MONITOR
31-00438—01 6
Table 2. Modbus Register Table.
Starting
Register
Decimal Data Description Function
Read/
Write
Quantity of
Registers
(2Bytes/16bit) Format Decimals
Data Range,
Data Description Default
0/1050 PM2.5 hourly average
measurement
4 R 2 Float-Big
Endian
1 0–1000.0 μg/m3
2/1052 PM10 hourly average
measurement
4 R 2 Float-Big
Endian
1 0–1000.0 μg/m3
8/1058 CO2hourly average
measurement
4 R 2 Float-Big
Endian
0 0–5,000 ppm
10/1060 TVOC hourly average
measurement
4 R 2 Float-Big
Endian
3 0–4000 mg/m3
12/1000 PM2.5 one minute average
measurement
4 R 2 Float-Big
Endian
1 0–1000.0 μg/m3
14/1002 PM10 one minute average
measurement
4 R 2 Float-Big
Endian
1 0–1000.0 μg/m3
16/1004 Temperature real-time
measurement
4 R 2 Float-Big
Endian
2 -20.00 °C–60.00 °C
18/1006 Humidity real-time
measurement
4 R 2 Float-Big
Endian
2 0–100.00% RH
20/1008 CO2real-time measurement 4 R 2 Float-Big
Endian
0 0–5,000 ppm
22/1010 TVOC real-time measurement 4 R 2 Float-Big
Endian
3 0–4000 mg/m3
24/1100 PM2.5 24-hour moving
average measurement
4 R 2 Float-Big
Endian
1 0–1000.0 μg/m3
26/1102 PM10 24-hour moving
average measurement
4 R 2 Float-Big
Endian
1 0–1000.0 μg/m3
32/1108 CO224-hour moving average
measurement
4 R 2 Float-Big
Endian
0 0–5,000 ppm
34/1110 TVOC 8-hour moving average
measurement
4 R 2 Float-Big
Endian
3 0–4000 mg/m3
1300 Primary pollutant 24-hour
average measuring value (One
of PM2.5/PM10/CO2/
TVOC) (Calculated based on
24-hour or
1-hour moving average
measurement)
4 R 2 Float-Big
Endian
1300
1302 Primary pollutant type (One of
PM2.5/PM10/CO2/
TVOC) (Calculated based on
24-hour or
1-hour moving average
measurement)
4 R 1 INT16 1-PM25, 2-PM10, 3-
CO2; 4-TVOC
1303 Index level of the primary
pollutant (One of
PM2.5/PM10/CO2/
TVOC) (Calculated based on
24-hour or
1-hour moving average
measurement)
4 R 1 INT16 Level 1-Excellent
Level 3-Light
pollution
Level4-Medium
pollution
Level 5-Heavy
pollution
Level 6-Severe
pollution

C7355B IN-DUCT IAQ MONITOR
731-00438—01
In order to reserve the decimal part, the measuring value with decimal will be magnified 10/100/1000 times, marked as
x10/x100/x1000.
1304 AQI value of the primary
pollutant) (One of
PM2.5/PM10/CO2/
TVOC) (Calculated based on
24-hour or
1-hour moving average
measurement)
4 R 1 INT16 0–500
1320 PM2.5 AQI value (Calculated
based on 24-hour moving
average measurement)
4 R 1 INT16 0–500
1321 PM10 AQI value (Calculated
based on 24-hour moving
average measurement)
4 R 1 INT16 0–500
1322 CO2AQI value (Calculated
based on 24-hour moving
average measurement)
4 R 1 INT16 0–500
1323 TVOC AQI value (Calculated
based on 24-hour moving
average measurement)
4 R 1 INT16 0–500
1350 PM2.5 Pollution index level
(Calculated based on 24-hour
moving average measurement)
4 R 1 INT16 1–6
1351 PM10 Pollution index level
(Calculated based on 24-hour
moving average measurement)
4 R 1 INT16 1–6
1352 CO2Pollution index level
(Calculated based on 24-hour
moving average measurement)
4 R 1 INT16 1–6
1353 TVOC Pollution index level
(Calculated based on 24-hour
moving average measurement)
4 R 1 INT16 1–6
78 3 color LED status 4 R 1 INT16 0-OFF, 1-Green,
2-Yellow, 3-Red
0 Modbus Address 3/6 R/W 1 UINT16 1–247 1
1 Modbus rate (bps) 3/6 R/W 1 UINT16 1-4800, 2-9600,
3-14400, 4-19200,
5-38400, 6-56000,
7-57600, 8-115200
2
2 Modbus Parity check bit 3/6 R/W 1 UINT16 1-NONE, 1STOP_BIT,
2-NONE, 2STOP_BIT,
3-Odd, 1STOP_BIT,4-
Even, 1STOP_BIT
1
4 Temperature correction value 3/16 R/W 2 Float-Big
Endian
2 -3.0–3.0 °C/
-6.0–6.0 °F
-2.0
6 Humidity correction value 3/16 R/W 2 Float-Big
Endian
2 -5.0–5.0%RH 0
14 CO2compensation value 3/16 R/W 2 Float-Big
Endian
0 -300.0–300.0 ppm 0
Table 2. Modbus Register Table.
Starting
Register
Decimal Data Description Function
Read/
Write
Quantity of
Registers
(2Bytes/16bit) Format Decimals
Data Range,
Data Description Default

C7355B IN-DUCT IAQ MONITOR
31-00438—01 8
CORRECTION AND
CALIBRATION
Regular Correction
In order to ensure the accuracy of the measured value, the
C7355B should be corrected every year. The correction
should be carried out when a large deviation in the
measured value occurs even if it has been used for less
than one year.
This chapter describes the correction environment and
requirement needed on user's site, the correction could be
carried out by user via RS-485.
The following environment conditions are required for
field correction.
CORRECTION ENVIRONMENT:
Temperature: 68 °F to 77 °F (20 to 25 °C)
Humidity: 40% to 50% RH
The C7355B needs to be placed in the indoor natural
environment within the above temperature and
humidity range. There should be windows and no
human interference with good air circulation.
The room area for correction should not be less than
325 ft2(30 m2).
CALIBRATION STANDARDS NEEDED FOR ON-SITE
CORRECTION.
PM2.5/PM10
PM2.5/PM10 calibration standard: A PM2.5 instru-
ment, such as TSI 8533, or a new C7355B device.
After PM2.5 calibration standard and C7355B that
needs to be corrected are powered on continuously
and synchronously for more than 10 minutes, record
the PM2.5 value for 30 minutes, the synchronous
average value over 30 minutes can be applied for
correction.
Starting
Register
Decimal Data Description Function
Read/
Write
Quantity of
Registers
(2Bytes/16bit) Format Decimals
Data Range,
Data Description Default
50/1175 PM2.5 hourly average
measurement x10
4 R 1 UINT16 1 0–10000 corresponding to
0–1000.0 μg/m3
51/1176 PM10 hourly average
measurement x10
4 R 1 UINT16 1 0–10000 corresponding to
0–1000.0 μg/m3
54/1179 CO2hourly average
measurement x1
4 R 1 UINT16 0 0–5000 corresponding to
0–5,000 ppm
55/1180 TVOC hourly average
measurement x1000
4 R 1 UINT16 3 0–3575 corresponding to
–4.000 mg/m3
56/1150 PM2.5 one minute average
measurement x10
4 R 1 UINT16 1 0–10000 corresponding to
0~1000.0 μg/m3
57/1151 PM10 one minute average
measurement x10
4 R 1 UINT16 1 0–10000 corresponding to
0–1000.0 μg/m3
58/1152 Temperature real-time
measurement x100
4 R 1 INT16 2 -2000–6000
corresponding to
-20.00 °C–60.00 °C
59/1153 Humidity real-time
measurement x100
4 R 1 UINT16 2 0–10000 corresponding to
0–100.00% RH
60/1154 CO2real-time measurement
x1
4 R 1 UINT16 0 0–5000 corresponding to
0–5,000 ppm
61/1155 TVOC real-time measurement
x1000
4 R 1 UINT16 3 0–3575 corresponding to
–4.000 mg/m3
62/1200 PM2.5 24-hour moving
average measurement x10
4 R 1 UINT16 1 0–10000 corresponding to
0–1000.0 μg/m3
63/1201 PM10 24-hour moving
average measurement x10
4 R 1 UINT16 1 0–10000 corresponding to
0–1000.0 μg/m3
66/1204 CO224-hour moving average
measurement x1
4 R 1 UINT16 0 0–5000 corresponding to
0–5,000 ppm
67/1205 TVOC 24-hour moving average
measurement x1000
4 R 1 UINT16 3 0–3575 corresponding to
0–4.000 mg/m3

C7355B IN-DUCT IAQ MONITOR
931-00438—01
Temperature and humidity
Temperature and humidity calibration standard: com-
mercial or industrial temperature and humidity cali-
bration standard.
After the temperature and humidity calibration stan-
dard and C7355B that needs to be corrected are
powered on continuously and synchronously for
more than 60 minutes, start to record the value of
temperature and humidity for 10 minutes, use the
synchronous average value within 10 minutes over
correction.
CO2
CO2calibration standard: e.g. CO2transmitter. Outdoor
CO2reference value is about 380ppm-420ppm.
After the CO2calibration standard and C7355B that
needs to be corrected are powered on continuously
and synchronously for more than 48 hours, the CO2
value shall be continuously recorded for 30 minutes,
use the synchronous average value over 30 minutes
for correction.
TVOC
TVOC calibration standard:
TVOC sensors produced by different manufacturers
are sensitive substances at difference levels, it is
recommended to use a new C7355B as the TVOC
calibration standard
After the TVOC and C7355B that needs to be corrected
are powered on continuously and synchronously for
more than 48 hours, record the TVOC value continu-
ously for 30 minutes and use the synchronous aver-
age value over 30 minutes for correction TVOC value
will be stable only after correction and at least 24
hours power-on.
Measurements Adjustment Via
Modbus:
1. Temperature
2. Humidity
3. CO2
4. TVOC coefficient
5. Particle coefficient
Use MODBUS PC software to operate according to the
following table:
MAINTENANCE & FAULT
CHECK
Maintenance
To ensure accurate C7355B data, regular maintenance is
required in normal use environments. Depending on the
environment in which it is used, maintenance is usually
required once every 3 months. Public places with high
concentration of dust, dry seasons, pollen seasons, and
poor environmental cleanliness can shorten the
maintenance period.
Maintenance should include: cleaning of the outer casing,
internal structure cleaning, air inlet filter cleaning, and
module cleaning.
Regular Maintenance
1. Cleaning of the inlet filter: The general maintenance
period is every 3 months.
2. Cleaning of internal structure: The general mainte-
nance period is every 12 months.
3. Sensing module cleaning: The general maintenance
period is every 12 months.
Table 3. Measurement Adjustment via MODBUS.
Temperature
value adjustment
RH value
adjustment
CO2value
adjustment
TVOC coefficient
adjustment
Particle total
environmental
coefficient
adjustment
Function code 3(Read)/16(Write) 3(Read)/16(Write) 3(Read)/16(Write) 3(Read)/16(Write) 3(Read)/16(Write)
Starting point
(Base 0)
4 6 14 12 1224
Data length 2 2 1 2 2
Data type 32 Bit Float
Big-endian
32 Bit Float
Big-endian
INT16 32 Bit Float
Big-endian
32 Bit Float
Big-endian
Setting value Standard reading -
C7355A local
temperature
measured value
Standard reading -
C7355A local
humidity measured
value
Standard reading -
C7355A local CO2
measured value
Standard
reading/TVOC
local measured
value
Standard reading X
C7355A local
PM2.5 average
measured value
Setting range -9.00–+9.00 °F(--
5.00–+5.00 °C)
-10.00–
+10.00%RH
-300–+300 ppm 0.001–65.000
times
0.001–10.000
times

C7355B IN-DUCT IAQ MONITOR
31-00438—01 10
Maintenance Procedure
1. Open the upper compartment of the main unit.
Fig. 11.
2. Remove the dust filter next to the air inlet of the sensor module, clean the filter.
Fig. 12.

C7355B IN-DUCT IAQ MONITOR
11 31-00438—01
3. Remove the mounting screw on the middle of the sensor module, take out the sensor module, and clean the sensor
module inlet and outlet, use compressed air to clean the sensor module inside.
Fig. 13.
4. Assembling the senor module after cleaning
Fig. 14.
STEP 3-1 STEP 3-2
STEP 3-3 STEP 3-4
STEP 4-1 STEP 4-2 STEP 4-3 STEP 4-4

C7355B IN-DUCT IAQ MONITOR
® U.S. Registered Trademark
©2020 Honeywell International Inc.
31-00438—01 M.S. 11-20
Printed in United States
Honeywell Building Technologies
Honeywell
715 Peachtree Street NE
Atlanta, GA 30308
customer.honeywell.com
Honeywell Building Technologies
Honeywell GmbH
Böblinger Strasse 17
71101 Schönaich, Germany
buildings.honeywell.com
Fault Check
If a fault occurs in a normal use environment, see Table 4 to troubleshoot. If the fault cannot be eliminated, contact the
dealer or the manufacturer.
Waste Electrical and Electronic
Equipment (WEEE)
FCC Part 15 compliant
This device complies with part 15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2)This device must accept any interference received,
including interference that may cause undesired
operation.
Table 4. Fault Check-out.
Fault condition Troubleshooting
PM2.5 data abnormal, deviation is too
large, the value is too high or too low
Check whether there is debris or a lot of dust in the C7355A housing or on the
air inlet and air outlet.
The CO2data is abnormal, the value is
too high or too low
The CO2sensor has a self-calibration function inside. Usually the self-
calibration will return CO2values to normal. Self-calibration conditions: The
CO2concentration is around 400 ppm for at least 4 hours in every 24 periods.
The self-calibration environment should last for one week.
TVOC's deviation is too large (high or
low)
TVOC in the environment needs to be stabilized for at least 48 hours after the
sensor is powered on.TVOC data deviation may be a little large within a short
time after power is on. TVOC base line deviation may result in large data
deviation.The equipment can be placed outside the window or outdoors for at
least 24 hours when the outdoor air is good and clear, allowing TVOC to retrace
its baseline.
Temperature and humidity deviation is
too large, the value is too high or low
Check whether the environmental factors surrounding the C7355B has any
influence, such as direct sunlight, close to the heating or air conditioning air
outlets, etc.
Temperature and humidity deviation is
too large; value does not change for a
long time
Sensor can be powered off and back on to see if the reading returns to normal. If
value cannot be recovered, contact the dealer or manufacturer.
Communication interruption RS-485
(Modbus RTU)
Check if the power supply is normal and if the RS-485 terminal is loose. Check
whether the RS-485 communication line is accidentally cut. Check for an
inductive load with electromagnetic interference near the equipment or RS-485
communication line, such as a water pump.
•At the end of the product life, dispose
of the packaging and product in an
appropriate recycling center.
•Do not dispose of the device with the
usual domestic refuse.
•Do not burn the device.