LI-COR LI-840/A User manual

LI-840A
CO
2
/ H2 O GAS ANALYZER
Instruction Manual

LI-840A
CO2/H2O Analyzer
Instruction Manual
i

Federal Communications Commission
Radio Frequency Interference Statement
WARNING: This equipment generates, uses, and can radiate radio frequency energy and if not
installed in accordance with the instruction manual, may cause interference to radio
communications. It has been tested and found to comply with the limits for a Class A computing
device pursuant to Subpart J of Part 15 of FCC rules, which are designed to provide a reasonable pro-
tection against such interference when operated in a commercial environment. Operation of this
equipment in a residential area is likely to cause interference in which case the user, at his own
expense, will be required to take whatever measures may be required to correct the interference.

Lead (Pb) Mercury (Hg) Cadmium (Cd)
Chromium VI
Compounds
(Cr6+)
Polybrominated
Biphenyls
(PBB)
Polybrominated
Diphenyl Ethers
(PBDE)
Optical Bench Assembly
Source Block Assembly
Detector Block Assembly
Ribbon Cable Assembly
ylbmessAelbaClaireS
LED Circuit Board Assembly
tiKelbaC232-SR
Main Board V2 Circuit Board Assembly
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specified in the SJ/T 11363-2006 Industry Standard (Company can explain the technical reasons for the "X")
Hazardous Substances or Elements
Component Name
LI-840A
O: this component does not contain this hazardous substance above the maximum concentration values in homogeneous materials
specified in the SJ/T 11363-2006 Industry Standard.
X: 㺘⽪䈕ᴹ∂ᴹᇣ⢙䍘㠣ቁ൘䈕䜘ԦⲴḀа൷䍘ᶀᯉѝⲴ䟿䎵ࠪSJ/T 11363-2006 ḷ߶㿴ᇊⲴ䲀䟿㾱≲o(Աъ൘↔༴,
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LI-840A CO2/H2O࠶󰵡Ԛ䜘Ԧ〠ᴹ∂ᴹᇣ⢙䍘ᡆݳ㍐O: 㺘⽪䈕ᴹ∂ᴹᇣ⢙䍘൘䈕䜘Ԧᡰᴹ൷䍘ᶀᯉѝⲴ䟿൷൘SJ/T 11363-2006 ḷ߶㿴ᇊⲴ䲀䟿㾱≲ԕлo
Doc. #53-13776-A
May 21, 2013 Page 1 of 1
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LI-COR, inc.
Environmental
4647 Superior Street
P.O. Box 4425
Lincoln, Nebraska 68504 USA
Phone: [phone]
FAX: [phone]
Toll-free: 1-800-447-3576 (U.S. & Canada)
E-mail: [email protected]m
Declaration of Conformity
Manufacturer's Name: LI-COR Inc.
Manufacturer’s Address: 4647 Superior Street
Lincoln, Nebraska USA 68504
This declaration of conformity is issued under the sole responsibility of the manufacturer.
Product Description: The LI-840A is a CO2 and H2O Gas Analyzer.
Product Name: Gas Analyzer
Model Number(s): LI-840A, LI-840-01, LI-840A-02
Product Options: None
This product complies with the requirements of the EMC Directive 2004/108/EC, and the RoHS
Directive 2011/65/EU, and carries the CE marking accordingly.
Harmonized Standard Product Specifications:
EMC:
EN 55011 : 2009/A1:2010 Radiated Emissions, Class A
EN 55011 : 2009/A1:2010 Conducted Emissions, Class A
EN 61326-1:2006 Electrical equipment for measurement, control and laboratory use
IEC 61000-4-2 : 2008 ESD, 4KV/8KV Contact/Air
IEC 61000-4-3 : 2006/A1:2007/A2:2010 Radiated RF Immunity, 10V/m
IEC 61000-4-4 : 2012 EFT/Burst
IEC 61000-4-5 : 2005 Surge
IEC 61000-4-6 : 2008 Conducted RF Immunity
IEC 61000-4-8 : 2009 H-Field Immunity, 3A/m
IEC 61000-4-11 : 2004 Voltage Dips
FCC 47 CFR Part 15.109 Radiated Emissions, Class A
FCC 47 CFR Part 15.107 Conducted Emissions, Class A
Note:
This document is serial number specific.
Adherence to the EMC testing standards listed above is claimed for the non-OEM version of the LI-840A.
EMC performance can be affected by the complete installation, therefore if using OEM versions (LI-840-
01 and LI-840A-02), the final equipment manufacturer should re-qualify the complete system to the EMC
Directive.
____________________________
Document #53-13759-A- John Rada
Engineering Manager
May 21, 2013
®
Page 1 of 1

NOTICE
The information contained in this document is subject to change without notice. LI-COR MAKES NO WARRANTY OF ANY KIND WITH
REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE. LI-COR shall not be liable for errors contained herein or for incidental or consequential damages
in connection with the furnishing, performance, or use of this material.
This document contains proprietary information which is protected by copyright. All rights are reserved. No part of this document may be
photocopied, reproduced, or translated to another language without prior written consent of LI-COR, Inc.
© Copyright 2010-2016, LI-COR, Inc.
Publication Number: 984-10690
Printing History
April 2010
January 2011
Updated May 2013; May 2015; June 2016
New editions of this manual will incorporate all material since the previous editions. Update packages may be used between editions which
contain replacement and additional pages to be merged into the manual by the user.
The manual printing date indicates its current edition. The printing date changes when a new edition is printed. (Minor corrections and
updates which are incorporated at reprint do not cause the date to change).
LI-COR, Inc. • 4421 Superior Street • Lincoln, Nebraska 68504
Phone: [phone] • FAX: [phone]
Toll-free: 1-800-447-3576 (U.S. & Canada)
e-mail: [e-mail] • www.licor.com

Table of Contents
Section 1. General Description
What's What 1-1
Features 1-3
Precautions 1-3
Getting Started Tutorial 1-4
Section 2. Power On
Alarms 2-1
Section 3. Operation
Installing the PC Communication Software on Your Computer 3-1
Setting the Communication Parameters 3-2
Cabling 3-2
RS-232 Output 3-2
Initial Setup 3-3
v

Using the Toolbar 3-6
Settings Window - Setting Operational Parameters 3-7
Enable Heater 3-8
Pressure Compensation 3-8
Filter 3-8
DAC Output 3-8
CO2 Span Range 3-13
Alarms 3-13
Using the Terminal Strip 3-14
Software Reference 3-16
Charting Window 3-16
Series 1 3-17
Series 2 3-17
X-Axis Max 3-17
Diagnostic Window 3-18
Logging Data 3-19
Start Logging 3-19
Stop Logging 3-20
Pause Logging 3-20
Options 3-21
User Calibration - Setting the Zero and Span 3-23
Two Point Span (Span 2 Tab) 3-26

Considerations for performing a secondary span 3-28
Coefficients Page 3-29
Advanced Page 3-30
Connecting the LI-840A to the LI-1400 Datalogger 3-32
Section 4. Theory of Operation
System Overview 4-1
Optical Bench System 4-2
Section 5. Maintenance
Cleaning the Optical Bench 5-1
Changing the Fuse 5-5
Note on Infrared Source Replacement 5-6
Storing the LI-840A 5-7
Appendix A. Specifications

Appendix B. Equation Summary
Appendix C. Pin Assignments
Appendix D. Suppliers
Appendix E. Configuration Grammar
Element Descriptions E-15

Section 1. General Description
What's What
This procedure should be followed if you have just taken delivery of your LI-840A. Check the
packing list to verify that you have received everything that was ordered and that you have also
received the following items:
lRS-232 Cable - (Part #392-04993), used to connect the LI-840A to your computer. This cable
is a null modem (cross-over) type cable; a straight through type cable will not work with the
LI-840A. Appendix C shows the pin assignments for the DB-9 connector on the LI-840A front
panel. An RS-232-to-USB converter is provided as well (Part # 6400-27)
lData Communications Software - This Windows® 7, 8/8.1, and 10 compatible software is
used for communication between the LI-840A and a computer. The software is provided on
CD. A complete description of this software can be found in Operation on page3-1.
Section 1. General Description 1-1

lStandard Spare Parts Kit (9980-021) - This kit contains replacement parts for the LI-840A.
As you become familiar with the analyzer you will learn which items to keep close at hand
and which items can be stored away. The spare parts kit contains these items:
Description Qty. LI-COR Part No.
Spares Kit: 1 9980-021
Polyurethane Mounting Feet 4 234-02268
Mounting Screws 4 149-02610
Terminal Block 1 331-05273
Bev-a-line Tubing 12' 222-01824
Gelman Air Filter 2 9967-008
Quick Connect Unions 2 300-03123
Rapid Tube Fitting Nut 2 9861-036
2A Fuse 2 439-03952
Cleaning Kit: 1 9980-013
5" Cleaning Swabs 5 610-05315
O-Rings 4 192-00226
Pre-formed Optical Bench Tubing 4 6580-010
Section 1
1-2 Section 1. General Description

Features
The LI-840A is an economical, high performance, non-dispersive infrared gas analyzer designed
to be used for a wide variety of applications. Some of the LI-840A's important features include:
lA 14 cm (5.5") optical bench is used to obtain a CO2measurement range of 0-20,000 ppm
(parts per million, or µmol/mol) and an H2O measurement range of 0-60 mmol/mol.
lThe optical bench is fully serviceable by the user; cleaning the optical bench is a simple pro-
cess, and does not affect the instrument's factory calibration.
lSimple Windows® software provides for easy user calibration and data output.
Precautions
lAvoid storing the LI-840A in humid conditions while powered off. Doing so can cause the
optical sensor to become saturated with humidity, which will temporarily affect meas-
urements when the instrument is removed from storage. See Storing the LI-840A on page5-7
for more details.
lThe optical bench is maintained at a constant temperature of about 50 °C. Avoid direct expos-
ure to sunlight or extremely high temperatures that may elevate the temperature inside the
LI-840A case.
lThe optical source is sensitive to vibration, and can be damaged by strong vibrations or jar-
ring. Do not drop the LI-840A or expose it to severe mechanical shock.
1-3Section 1. General Description
Section 1

lDo not use abrasive cleansers when cleaning the optical bench, as damage to the gold plating
may result. Instructions for cleaning the optical bench can be found in Section 5.
lAlways filter air entering the LI-840A. Two Gelman filter assemblies (p/n 9967-008) are
included in the spares kit.
Getting Started Tutorial
The following section briefly covers the basic steps you might follow to set up the LI-840A to col-
lect and record data. Many of these steps are described in greater detail throughout this manual.
1Install the PC Communications Software.
This software is used to set the zero and span of the LI-840A and set up data communication and
data transfer parameters for viewing and logging data. Installation instructions can be found in
Installing the PC Communication Software on Your Computer on page3-1.
2Determine your jumper settings for high and low alarm output, if required.
There are 2 jumpers inside the LI-840A case (on the main circuit board), which toggle the high
and low alarm output between 0-5V (TTL levels) and an open drain condition. The default
jumper positions are set for 0-5V output for both high and low alarms. This alarm configuration
is suitable for logic devices such as dataloggers. To use the high and/or low alarms to operate a
relay switch, the jumpers should be reconfigured for open drain output. See Alarms on page2-1,
for a description of how to change the alarm jumper settings.
Section 1
1-4 Section 1. General Description

If the default jumper positions are suitable for your application, or if you do not intend to use
the alarms, proceed to Step 3.
3Connect a power source to the LI-840A
The LI-840A requires an input voltage of 12-30 VDC. The power supply must be able to source a
maximum current drain of 1.2A (at 12 VDC). After the instrument has warmed up it will draw
about 0.3A (at 12 VDC) with the heaters on.
+-
1 2 3 4 5 6 78 9 10 11 12 13 14
Bare wire leads are connected to the terminal strip at positions 1 and 2. Connect the positive lead
(usually red) to position #1 (12-30VDC), and the negative lead to position #2 (GND).
NOTE: Pull straight out on the face of the terminal strip to remove it; this can make it easier
to connect the wires.
1-5Section 1. General Description
Section 1

4Connect the RS-232 cable.
Connect one end of the serial cable to the 9-pin Serial I/O port on the LI-840A front panel, and
the other end to a serial port on your computer. If you want to interface to a device with a 25-pin
serial port, a 9-pin to 25-pin adapter must be used; a gender changer may be required in some
cases. Tighten the two screws on the ends of the serial cable.
5Connect other output device(s) if desired.
Output devices such as dataloggers and relay switches for high and low alarms are connected via
the terminal strip. A complete description of the terminals can be found in Section 3, Using the
Terminal Strip.
6Connect an air pump and external power source.
The LI-840A sample cell must be continually flushed while making measurements, which
requires an external air pump that supplies a flow rate of between 0.25 and 1.0 liters per minute.
LI-COR offers a Diaphragm Pump under part number 286-04198 that is suitable for use with
the LI-840A. One pump plumbing option is shown below.
Section 1
1-6 Section 1. General Description

1/4" O.D.
Bev-A-Line
Diaphragm
Pump
Quick Connect
Sample Air
Exhaust
Quick Connect
with Regulator Quick Connect ‘Y’
Quick Connect ‘L’
Flow Meter
(set to 1 LPM)
IN
LI-840/A
Filter - Gelman
or Balston
µ
P
a
r
t
#
9
9
6
7
-
0
0
8
I
N
1
µ
m
P
T
F
E
I
N
NOTE: More information about plumbing options and parts available from LI-COR can be
found in Application Note #IRG4-105, entitled ‘Air Pumps and Accessories for LI-COR Gas Ana-
lyzers - Suggested Parts and Vendors’, which can be downloaded from www.licor.-
com/env/support.
1-7Section 1. General Description
Section 1

7Connect the input air stream and external filter.
Remove the nut from the FLOW IN fitting and conect a short (12" or so) piece of Bev-a-line
tubing (from the spares kit) . Tighten the nut. Place a Geman filter (also from the spares kit) in
the sample airstream before it enters the FLOW IN port on the LI-840A. A user-supplied pump is
required to force air through the LI-840A.
IMPORTANT: Always install the external air filter before operating the LI-840A. Insert filter
into the input airstream before it enters the LI-840A. Failure to do this will lead to con-
tamination of the optical path.
μ
P
a
r
t
#
9
9
6
7
-
0
0
8
I
N
1
μ
m
P
T
F
E
I
N
Air In
Air Out
When using the LI-840A for applications where sample air is particularly dirty, you may con-
sider stacking two filters in series. For maintenance, replace the filter furthest upstream from the
analyzer with the filter closest to the analyzer and replace the filter closest to the analyzer with a
new filter.
Install the new filter(s) with the blue lettering facing away from the FLOW IN port.
The air inlet and outlet ports should be covered with the dust caps provided or attached to an air
line when the instrument is not in use. This will prevent dust from entering the instrument
downstream from the filters where it can enter the optical path.
Replacement Gelman Acro 50 filters can be obtained from LI-COR (part #9967-008).
Section 1
1-8 Section 1. General Description

8Start the PC Communications Software.
Click on the program icon to start the application. The Main window appears. Select Connect
from the File menu. Choose the serial port to which the LI-840A is connected, and the data out-
put interval. Click the Connect button. If the analyzer is connected properly, data will appear in
the main window.
9Configure the analyzer.
Select Settings from the View menu. The Settings window appears. Choose a value for signal
averaging (the Filter field), between 0 and 20 seconds. Set values for high and low alarms and
corresponding dead bands, if desired. See Alarms on page2-1 for a complete description of the
alarms. If you are using an output device to collect data, choose the value to be output at DAC 1
and/or DAC 2. Make sure the Enable Heater and Pressure Compensation buttons are enabled
(checked), and click OK.
1-9Section 1. General Description
Section 1

10 Set the analyzer zero.
NOTE: The LI-840A is calibrated at the factory before shipping. It is recommended, however,
that you verify the calibration by connecting a gas with known concentration and reading the
displayed value. If the instrument needs to be calibrated, follow the steps below.
Connect a dry, CO2-free gas to the input air stream. Select Calibration from the View menu.
Click on the Zero tab. Click the Zero CO2. Wait up to 15 minutes for any water vapor to clear
from the optical cell, then click the Zero H2Obutton. After several seconds, a message will
appear that indicates the IRGA is zeroed.
Section 1
1-10 Section 1. General Description