Vaisala AQT400 User manual

M211930EN-A
User Guide
Air Quality Transmitter
AQT400

PUBLISHED BY
Vaisala Oyj
Street address: Vanha Nurmijärventie 21, FI-01670 Vantaa, Finland
Mailing address: P.O. Box 26, FI-00421 Helsinki, Finland
Phone: [phone]
Fax: [phone]
Visit our Internet pages at www.vaisala.com.
© Vaisala Oyj 2017
No part of this manual may be reproduced,
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(including photocopying), nor may its
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based on the original English versions. In
ambiguous cases, the English versions are
applicable, not the translations.
The contents of this manual are subject to
change without prior notice.
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information contained in this manual.
Vaisala makes no representations on this
manual’s compliance with the local rules
and regulations applicable at any given
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responsibilities related thereto.
This manual does not create any legally
binding obligations for Vaisala towards
customers or end users. All legally binding
obligations and agreements are included
exclusively in the applicable supply
contract or the General Conditions of Sale
and General Conditions of Service of
Vaisala.
This product contains software developed
by Vaisala or third parties. Use of the
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Group.
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then such OSS is governed by the terms
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licenses are included in the product itself
or provided to you on any other applicable
media, depending on each individual
product and the product items delivered
to you.

Table of Contents
1. About This Document........................................................................................ 5
1.1. Version Information............................................................................................... 5
1.2. Documentation Conventions................................................................................ 5
2. Product Overview................................................................................................ 7
2.1. Introduction to AQT400........................................................................................7
2.2. Safety.......................................................................................................................8
2.2.1. ESD Protection.................................................................................................9
2.3. Regulatory Compliances....................................................................................... 9
3. System Functional Description......................................................................11
4. Installation.............................................................................................................13
4.1. Selecting Location................................................................................................ 13
4.2. Unpacking..............................................................................................................13
4.3. Installing to Mast or Wall..................................................................................... 13
4.4. Connecting Cables............................................................................................... 14
4.5. Using Serial Interfaces......................................................................................... 14
4.6. Switching on Power Supply.................................................................................15
5. Measurements......................................................................................................17
5.1. Stabilization Period.............................................................................................. 17
5.2. Measured Variables...............................................................................................17
5.3. Measuring Units.................................................................................................... 17
5.4. Impact of Ambient Conditions............................................................................17
6. Configuration and Operation........................................................................ 19
6.1. Installing AQT Configuration Tool...................................................................... 19
6.2. Using AQT Configuration Tool............................................................................ 19
6.3. Connecting to Management Console.................................................................21
6.4. Using General Commands.................................................................................. 22
6.5. Using Configuration Parameters........................................................................22
7. Data Formats.......................................................................................................25
7.1. Data Format in ASCII Mode................................................................................ 25
7.2. Data Format in Modbus Mode............................................................................25
8. Maintenance.........................................................................................................29
8.1. Overview to Maintenance...................................................................................29
8.2. Factory Calibration..............................................................................................29
8.3. Performance Check During Operation..............................................................29
9. Troubleshooting..................................................................................................31
9.1. Writing Problem Report.......................................................................................31
10. Technical Data.....................................................................................................33
10.1. AQT410 Specifications........................................................................................ 33
10.2. AQT420 Specifications....................................................................................... 35
Appendix A: Performance Check.......................................................................39
Appendix B: Accessories....................................................................................... 43
Table of Contents
1

Index............................................................................................................................... 45
Technical Support............................................................................................................47
Warranty...........................................................................................................................47
Recycling.......................................................................................................................... 47
AQT400 User Guide M211930EN-A
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List of Figures
Figure 1 Structure of AQT410 .............................................................................................8
Figure 2 Pin-out of M12 Connector...................................................................................14
List of Figures
3

List of Tables
Table 1 Document Versions................................................................................................5
Table 2 List of parameters................................................................................................22
Table 3 CSV Output Format.............................................................................................25
Table 4 Modbus Function Codes.................................................................................... 25
Table 5 Modbus Register Addresses............................................................................. 26
Table 6 Troubleshooting AQT400...................................................................................31
Table 7 Measuring Specifications...................................................................................33
Table 8 Gas Measuring Specifications...........................................................................33
Table 9 Electrical Specifications.....................................................................................34
Table 10 Environmental Specifications...........................................................................34
Table 11 Data Connection Specifications...................................................................... 34
Table 12 Mechanical Specifications................................................................................. 34
Table 13 Measuring Specifications...................................................................................35
Table 14 Gas Measuring Specifications...........................................................................35
Table 15 Particle Measuring Specifications................................................................... 36
Table 16 Electrical Specifications.....................................................................................36
Table 17 Environmental Specifications...........................................................................36
Table 18 Data Connection Specifications.......................................................................36
Table 19 Mechanical Specifications................................................................................. 37
AQT400 User Guide M211930EN-A
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1. About This Document
1.1. Version Information
This document provides information about the installation, operation, and maintenance of
Vaisala Air Quality Transmitters AQT400.
Table 1 Document Versions
Document Code Date Description
M211930EN October 2016 First version of this manual.
1.2. Documentation Conventions
Warning alerts you to a serious hazard. If you do not read and follow
instructions carefully at this point, there is a risk of injury or even death.
WARNING!
Caution warns you of a potential hazard. If you do not read and follow
instructions carefully at this point, the product could be damaged or important data
could be lost.
CAUTION!
Note highlights important information on using the product.
Tip gives information for using the product more eciently.
Lists tools needed to perform the task.
Chapter 1 – About This Document
5

Indicates that you need to take some notes during the task.
AQT400 User Guide M211930EN-A
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2. Product Overview
2.1. Introduction to AQT400
Vaisala Air Quality Transmitter AQT400 measures the pollution content of ambient air. The
AQT400 series consists of two products, AQT410 and AQT420. Both models measure four
gases (CO, NO2, SO2, and O3) and weather data, such as humidity, air pressure, and
temperature in the ambient air. AQT420 additionally includes a laser particle counter for
PM2.5 and PM10 particulate measurements.
You can send the measuring data from the air quality transmitter to local systems through a
serial interface.
AQT400 is enclosed in an IP65-rated weatherproof casing and can be installed outdoors.
The units are compact but robust with no moving parts and low power consumption.
AQT400 can be used in conjunction with a PC, data logger, or other device.
The following features and components are available in AQT410 and AQT420:
• Gas measuring (CO, NO2, SO2, and O3)
• Installation kit
• Installation cable
•Configuration cable
The following feature is available only in AQT420:
• Particle measuring (PM2.5 and PM10)
Chapter 2 – Product Overview
7

Figure 1 Structure of AQT410
1M12 connector
2Sensor elements (four sensors per unit)
3Main electronics board
4Combined temperature and humidity sensor
5Radiation shield
6Integrated pressure sensor
2.2. Safety
This product has been tested for safety. Note the following precautions:
Do not exceed the specified input voltage range.CAUTION!
AQT400 User Guide M211930EN-A
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2.2.1. ESD Protection
Electrostatic Discharge (ESD) can damage electronic circuits. Vaisala products are
adequately protected against ESD for their intended use. However, it is possible to damage
the product by delivering electrostatic discharges when touching, removing, or inserting any
objects in the equipment housing.
To avoid delivering high static voltages to the product:
• Handle ESD-sensitive components on a properly grounded and protected ESD
workbench or by grounding yourself to the equipment chassis with a wrist strap and a
resistive connection cord.
• If you are unable to take either precaution, touch a conductive part of the equipment
chassis with your other hand before touching ESD-sensitive components.
• Hold component boards by the edges and avoid touching component contacts.
2.3. Regulatory Compliances
This product complies with the following performance and environmental test standards:
• IEC/EN 61326-1:2013
• IEC/EN 61000-4-2/3/4/5/6
• CISPR 22
Chapter 2 – Product Overview
9

AQT400 User Guide M211930EN-A
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3. System Functional
Description
The gas measuring technology in AQT400 is based on proprietary advanced algorithms and
electrochemical technology.
The sampled gas causes a reduction or oxidation reaction in an electrochemical cell. Both
reactions create a weak electric current. The electric current is directly dependent on the
volume of measured gas. By measuring the electric current and using advanced calculation
and compensation algorithms, AQT400 calculates the gas content. Most electrochemical
cells are highly susceptible to ambient conditions (temperature and humidity), but AQT400
reverses the impact with a proprietary adjustment and compensation system, which
guarantees accurate ppb measurements.
The particle sensor technology of laser particle counter in AQT420 is based on the
scattering of laser light caused by passing particles. With the help of optics and
photosensitive sensors, the laser particle counter measures the angular scattering intensity
data and analyzes it with digital signal prosessing (DSP). The method allows simultaneous
measuring of two particle sizes, <2.5 and <10 µm.
The CPU of the air quality transmitter regularly controls the sampling pump to transfer
outside air into the gas analysis module for measuring. All measuring results are saved in the
CPU, from where they can be sent through a mobile network to a database or through a
serial interface to a local system (such as a PC).
Chapter 3 – System Functional Description
11

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4. Installation
4.1. Selecting Location
Compact and weatherproof AQT400 can be installed in a variety of outdoor locations. Install
the air quality transmitter in a location where adjacent walls, buildings, or other obstacles do
not influence the measuring results. Make sure other locally operated equipment, such as
radio transmitters, power lines, and generators, cannot aect the performance. Do not
mount the device in close proximity of high-powered radio transmitters. If you suspect
external electrical noise, order a site survey.
Protect AQT400 from direct sunlight in high temperatures. Fast temperature changes can
temporarily decrease the performance and direct sunlight can raise the operating
temperature over the allowed limit.
4.2. Unpacking
Remove the air quality transmitter from its cardboard package and check that no visible
damage has occurred during transport. If you detect any damage, immediately contact your
carrier and Vaisala technical support.
4.3. Installing to Mast or Wall
Install the air quality transmitter to a height of 1.5 ... 4 m from the ground. Applicable local
standards and guidelines may influence the installation height.
To reduce the build-up of deposits, handle the unit with lint-free gloves and remove all
grease from the surface after the installation
Vaisala recommends to use the installation kit to install both models onto a mast or a wall.
1. Fix AQT400 to a mounting plate with three M3 screws.
2. Use U bolts included in the installation kit to mount the air quality transmitter, for
example, onto a mast. Optimally, the tube or mast is at least 3 mm thick and 35 … 45
mm in outside diameter.
3. Pass the M12 connection cable along the tube and use appropriate strain relief to the
cable.
Chapter 4 – Installation
13

4.4. Connecting Cables
Connect the 8-pin M12 connection cable to the male connector in AQT400, and manually
tighten the outer sleeve. Connect the other end of the connection cable to an external
power source or to any other necessary systems. Do not switch on the power source yet.
Only use the recommended cable types and lengths.
AQT400 uses 8 ... 30 V direct-current voltage. Use a power source that complies with this
voltage. The power source must be able to supply at least 5 W, although AQT400 normally
uses less power than that.
Isolate any unused cable wires at the terminating equipment/user end. To preserve the EMC
performance, maintain the cable screen integrity in places where the cables are cut and re-
connected, such as junction boxes, plugs and sockets.
Do not exceed the specified input voltage range.CAUTION!
In case of power failure, Vaisala recommends using a rechargeable battery or an
uninterrupted power source (UPS). If the unit loses power for a few seconds, it may disrupt
the measuring for several hours if the power supply is not redundant.
4.5. Using Serial Interfaces
The 8-pin M12 connector provides RS-232 and RS-485 serial interfaces which can be used to
change the settings or output measurements.
Figure 2 Pin-out of M12 Connector
1RS-232/RS-485 GND White
2RS-232 RX (input) Brown
3RS-232 TX (output) Green
4No connection (floating) Yellow
5RS-485 B (-) Grey
6RS-485 A (+) Pink
7Power GND Blue
8Power 8–30 VDC Red
AQT400 User Guide M211930EN-A
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RS-232 Serial Interface
The RS-232 interface is used to control AQT400 either with a command line interface or with
AQT Configuration Tool. Use the following settings:
• 115200 bps
• 8N1 (8 data bits, no parity, one stop bit)
• no flow control (disable with the command line interface)
RS-485 Serial Interface
The RS-485 interface is used to control AQT400 either with a command line interface or
with AQT Configuration Tool. RS-485 interface uses the following default settings:
• 4800 ... 115200 bps (default value is 9600 bps)
• 7E1 (7 data bits, even parity, one stop bit)
• 120 Ω termination
Change the serial interface and protocol settings through a control connection. The interface
supports the following data transfer protocols: Modbus ASCII and ASCII formatted text with
comma separated values.
When using the RS-485 interface, use a protected and twisted pair cable with both ends
terminated with a 120 ohm termination resistor. AQT400 has been terminated by default.
To remove the termination, contact Vaisala technical support.
4.6. Switching on Power Supply
Verify that AQT400 is properly connected to a power source and any other systems. Switch
on the power supply.
Chapter 4 – Installation
15

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5. Measurements
5.1. Stabilization Period
When AQT400 is switched on, let the unit stabilize for at least 24 hours before using the
measurement results. To ensure optimal measuring accuracy, Vaisala recommends a
stabilization period of 48 hours. The units take measurements during the stabilization
period, but they are marked as invalid.
5.2. Measured Variables
The measured variables have been configured to AQT400 at the factory. When the air
quality transmitter is on, it continuously takes measurements, regardless of how often the
measurements are sent to the database or printed out from the serial port. The
measurements of the particle counter are based on the number of particles sampled over a
period of sixty seconds. You can set the measuring interval to 1 ... 1440 minutes for both gas
and particle measuring.
5.3. Measuring Units
AQT400 reports the gas measurements as parts per million and the particles in µg/m3. The
temperature readings are in degrees, Celsius (°C) or Fahrenheit (°F). The air pressure is
represented in mbar. To change the reported units, use AQT Configuration Tool.
5.4. Impact of Ambient Conditions
The ambient conditions (temperature and relative humidity) can influence and distort the
measuring results. AQT400 includes a sophisticated compensation feature for eliminating
the distortion in a non-condensing environment. If the conditions change very fast (for
example, the relative humidity suddenly drops), there may be some measuring inaccuracy
that temporarily exceeds the specifications.
Chapter 5 – Measurements
17

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