Teledyne IR-7000 User Manual
OPERATING INSTRUCTIONS FOR
IR7000
NDIR Gas Analyzer
REV. 3
NDIR Gas Analyzer Safety
Copyright © 2000 Teledyne Analytical Instruments.
All Rights Reserved. No part of this manual may be reproduced, transmitted,
transcribed, stored in a retrieval system, or translated into any other language or computer
language in whole or in part, in any form or by any means, whether it be electronic,
mechanical, magnetic, optical, manual, or otherwise, without the prior written consent of
Teledyne Analytical Instruments, 16830 Chestnut St. City of Industry, Ca. 91748
Warranty
This equipment is sold subject to the mutual agreement that it is warranted by us to
be free from defects of material and of construction, and that our liability shall be limited
to replacing or repairing at our factory (without charge, except for transportation), or at
customer plant at our option, any material or construction in which defects become
apparent within one year from the date of shipment, except in cases where quotations or
acknowledgments provide for a shorter peri o d. C omponents manufactured by others bear
the warranty of their manufacturer. This warranty does not cover defects caused by wear,
accident, misuse, neglect or repairs other than those performed by Liston or an authorized
service center. We assume no liability for direct or indirect damages of any kind and the
purchaser by the acceptance of the equipment will assume all liability for any damage
which may result from its use or misuse.
We reserve the right to employ any suitable material in the manufacture of our
apparatus, and to make any alterations in the dimensions, shape or weight of any parts, in
so far as such alterations do not adversely affect our warranty.
Important Notice
This instrument provides measurement readings to its user, and serves as a tool by
which valuable data can be gathered. The information provided by the instrument may
assist the user in eliminating potential hazards caused by his process; however, it is
essential that all personnel involved in the use of the instrument or its interface be
properly trained in the process itself, as well as all instrumentation related to it.
The safety of personnel is ultimately the responsibility of those who control process
conditions. While this instrument may be able to provide early warning of imminent
danger, it has no control over process conditions, and it can be misused. In particular, any
alarm or control systems installed must be tested and understood, both as to how they
operate and as to how they can be defeated. Any safeguards required such as locks,
labels, or redundancy, must be provided by the user or specifically requested of Teledyne
Analytical Instruments at the time the order is placed.
Therefore, the purchaser must be aware of the hazardous process conditions.
The purchaser is responsible for the training of personnel, for providing hazard warning
methods and instrumentation per the appropriate standards, and for ensuring that hazard
warning devices and instrumentation are maintained and operated properly.
Teledyne Analytical Instruments cannot accept responsibility for conditions
beyond its knowledge and control. No statement expressed or implied by this document
or any information disseminated by the manufacturer or its agents, is to be construed as a
warranty of adequate safety control under the user’s process conditions.
Teledyne Analytical Instruments, - Rev. 3
Table of Contents
Important Safety Information....................................................S-1
S.1 General Format.............................................................S-1
S.2 Specific Hazards...........................................................S-2
Introduction....................................................................................1
1.0 Overview .......................................................................... 2
1.1 Standard Features........................................................... 4
1.2 Optional Features............................................................ 4
1.3 IR Detection ..................................................................... 6
1.4 Operator Interface........................................................... 6
Operational Theory........................................................................8
2.1 Introduction ..................................................................... 8
2.2 Optical Bench.................................................................. 8
2.3 Electronics..................................................................... 11
2.3.1 Power Supply Board........................................... 11
2.3.3 Main Board.......................................................... 12
2.3.4 Display Board...................................................... 14
2.3.5 I/O Board ............................................................. 14
2.4 Sample System.............................................................. 14
2.5 Internal Gas Handling System...................................... 16
Installation....................................................................................18
3.1 Overview ........................................................................ 18
3.2 Unpacking and Installation........................................... 18
3.3 Mounting the Analyzer.................................................. 18
3.4 Gas Connections........................................................... 19
3.5 Sample System Considerations................................... 20
3.6 Electrical Connections.................................................. 21
3.6.1 Analog Output..................................................... 22
3.6.2 Analog Output Connections.............................. 25
3.6.3 Solenoid Valve Connections.............................. 25
3.6.4 Optional Relay Outputs...................................... 26
3.6.5 Digital I/O Option ................................................ 27
3.6.6 RS-232 Cable....................................................... 28
3.6.7 Power Connections............................................ 29
Teledyne Analytical Instruments., - Rev. 3
NDIR Gas Analyzer Safety
Operation......................................................................................31
4.1 Overview ........................................................................ 31
4.2 The SETUP Menu........................................................... 31
4.3 The MODE Menu............................................................ 39
Calibration....................................................................................46
5.1 Overview ........................................................................ 46
5.2 Typical Sample System ................................................ 46
5.3 Manual Calibration........................................................ 47
5.3.1 Manual Zero Calibration..................................... 47
5.3.2 Manual Span Calibration.................................... 48
5.4 AUTO Calibration .......................................................... 50
5.5 Calibration Issues ......................................................... 51
Maintenance.................................................................................53
6.1 Scheduled Maintenance ............................................... 53
6.1.1 Cleaning .............................................................. 53
6.1.2 Particle Filter....................................................... 53
6.2 Service ........................................................................... 55
6.2.1 Removing the Optical Bench............................. 55
6.2.2 Cleaning the Sample Cell................................... 58
6.2.3 Replacing the IR Source .................................... 59
6.2.4 Replacing the Battery (Portable Model Only)... 59
6.2.5 Changing the Fuse ............................................. 60
6.3 Display Messages ......................................................... 61
6.3.1 Error Messages................................................... 62
6.3.2 Normal Operation Messages ............................. 65
6.3.3 Normal Operator Induced Messages ................ 66
Appendix ......................................................................................69
A-1 Specifications.................................................................... 69
A-2 Recommended Spare Parts List .................................. 71
A-3 RS-232 Communication Protocol .................................... 72
A-3.1 Codes for "e" Type Messages........................... 76
A-3.2 Codes for "s" Type Messages........................... 77
A-3.3 Codes for "c" Type Messages........................... 77
A-3.4 Codes for “m” Type Messages.......................... 78
A-3.5 Codes for “a” Type Messages........................... 78
Addendum A……………………………………………………………..
Configuration and Compliance Certificates
Addendum B……………………………………………………………..
Automatic Calibration Electrical Connection Diagram
Teledyne Analytical Instruments, - Rev. 3
Important Safety Information
S.1 General Format
Important information relating to health and safety of personnel,
possible equipment damage and special instructions regarding instrument
setup and operation are setoff and highlighted within this manual. The
following format will be used in this manual to indicate safety hazards and
special instructions:
Symbol Heading Typeface and
Description
WARNING 12 poi nt bol d t ypefa ce.
Contains important
informa tion w hi ch i f
ignored could result in
persona l in jury or dea th.
CAUTION 12 poi nt bol d t ypefa ce.
Contains important
informa tion w hi ch i f
ignored could result in
dam ag e t o t h e syst em.
NOTE
No Symbol
12 point Italic typeface.
Contains important or helpful
information relating to the
setup and/or operation of the
system.
Read this instruction manual carefully and familiarize yourself
thoroughly with its contents. Do not ignore any warnings or
cautions or operate this equipment with any safety feature
Safety IR7000
defeated or inoperable. Failure to heed warnings or cautions can
result in injury or death as well as damage to the instrument.
S.2 Specific Hazards
WARNING: ELECTRICAL HAZARD! Hazardous voltage is present inside. Keep
away from Live Circuits. Under no circumstances should untrained
personnel open any panel or remove any cover, lid or wiring
harness without proper guidance and supervision.
Component replacement, internal adjustments and electrical service
must be made by qualified maintenance personnel. Always disconnect the
power cable and discharge circuits before servicing the equipment. To
avoid accidental power up, Liston recommends using an electrical lockout device whenever maintenance is to be performed. Disconnect power to
any other equipment connected to the instrument to avoid the possibility
of component failure and transmission of dangerous voltage through
signal connections.
WARNING: FLAMMABLE GAS HAZARD! EXPLOSION HAZARD! TOXIC GAS
HAZARD! Do not operate this instrument in an explosive
atmosphere. Read all documentation that comes with this
instrument especially any application notes or addenda which,
among other important details, may specify the nature and
properties of the gas to be analyzed.
Unless specifically designed for hazardous environment application,
this instrument is not designed to handle explosive or flammable gases.
Exposed electrical terminals pose a substantial risk of ignition if powered
in the presence of flammable gas. The sample system is not appropriate
for handling toxic, flammable or explosive gases!
If your application requires using toxic, flammable or explosive gases
for analysis or calibration, please consult the factory. An explosion proof
instrument with enhanced sample system is available as an option.
WARNING: ELECTRICAL HAZARD! This instrument must be properly
grounded.
To avoid shock hazard, the instrument chassis and cabinet must be
connected to an electrical ground. The instrument is equipped with a three
conductor AC power cable. This cable must be plugged into an approved
three-contact electrical outlet. The power jack and plug of the power cable
meet International Electro-Technical Commission (IEC) safety standards.
When replacing this cable, use only the proper replacement cable as listed
in the Spare Parts Listing in the Appendix.
S-2 Teledyne Analytical Instruments., - Rev. 3
NDIR Gas Analyzer Safety
WARNING: Do not attempt to service or make adjustments to this equipment
while working alone.
Whenever servicing or adjusting this equipment, notify your supervisor
and have another person capable of rendering first aid standby in case of
an accident.
WARNING: Do not substitute parts or modify this instrument.
The IR7000 was designed and tested at the factory. The quality, safety and
workmanship inherent in this product is a result of careful design,
selection and assembly of components. Any use of non-authorized
replacement parts can impair the functioning of this system. In addition to
voiding your warranty, any substitution of non-authorized replacement
parts or unauthorized modifications to the instrument can create an
unnecessary risk of harm. Return the analyzer to Teledyne Analytical
Instruments for service and repair to ensure proper functioning of the unit.
WARNING: Do not operate a damaged instrument.
If any of the built-in safety features of this instrument is impaired,
either through physical damage, excessive moisture, or any other reason,
IMMEDIATELY REMOVE POWER. Do not use the instrument until
safe operation can be verified by service-trained personnel. If necessary,
return the instrument to Teledyne Analytical Instruments. for service and
repair.
DANGER
HIGHLY TOXIC AND/OR FLAMMABLE LIQUIDS MAY BE PRESENT IN THIS MONITORING SYSTEM
PERSONAL PROTECTIVE EQUIPMENT MAY BE REQUIRED WHEN SERVICING THIS SYSTEM.
HAZARDOUS VOLTAGES EXIST ON CERTAIN COMPO NENT S INTERNALLY WHIC H MAY
PERSIST FOR A TIME EV EN AFTER THE POWER IS TURNED OFF AND DISCONNECTED.
ONLY AUTHORIZED PERSONNEL SHOULD CONDUCT MAINTENANCE AND/OR SERVICING.
BEFORE CONDUCTING ANY MAINTENANCE OR SERVICING CONSULT WITH AN AUTHORIZED
SUPERVISOR OR MANAGER.
S-3 Teledyne Analytical Instruments., - Rev. 3
Safety IR7000
THIS PAGE INTENTIONALLY LEFT BLANK.
S-4 Teledyne Analytical Instruments., - Rev. 3
Introduction
Introduction 1 IR7000
1.0 Overview
The Teledyne analytical Instruments Model IR7000 Non-Dispersive
Infrared Gas Analyzer is a versatile microprocessor based analyzer for
measuring or monitoring a gas stream. The IR7000 analyzer is available in
a variety of configurations to suit most applications.
The IR7000 series analyzer is designed for rapid monitoring of a
process gas stream. Four user definable chart ranges are available for
accurate monitoring over the full range of the process gas composition. A
trace analysis unit is available for analysis at low ppm levels. This manual
describes the setup and operation of the Model IR7000. It also covers
particular features of the other analyzers in the IR7000 series where setup
and operation differs from the standard unit.
MODEL DESCRIPTION
IR7000 Panel/19” Rack Mount – CE Mark
IR7010 Split Architecture, Analysis Unit – Explosion Proof
IR7000P Portable Battery Operated with AC Charger
IR7000T Similar to IR7000 for Trace Analysis
2 Teledyne Analytical Instruments, - Rev. 3
NDIR Gas Analyzer Introduction 1
IR7000D Dual Optical Bench for Monitoring 2 Gases
IR7000B Wall Mount Unit
The standard rack mount model IR7000 is shown in Figure 1-1 and
the portable IR7000P is shown in Figure 1-2. The explosion proof models
have the analysis unit installed in an explosion proof housing and employ
steel tubing and fittings in the sample system. The control unit on these
models is separate from the analyzer and generally located outside the
hazardous environment.
Teledyne Analytical Instruments., - Rev. 3 3
Introduction 1 IR7000
1.1 Standard Features
The following features are standard on the IR7000 series of analyzers:
• User selected automatic zero and span calibration
• Linearized output over the entire full scale range eliminating
the need for separate instrument ranges to achieve full span
• Closed sample path is not exposed to ambient air eliminating
the need for purging of the cell compartment
• Four user-definable chart ranges plus auto-ranging
• Selectable analog output: 0–1, 0–5, or 0–10V or optionally, a
4–20mA non-isolated or isolated current output
• High and low alarms or limits with adjustable setpoints. The
alarms are configured at the factory for either latching or nonlatching operation
• Modular design for easy maintenance
• Configured to easily accommodate an optional oxygen channel
for simultaneous oxygen analysis at either 0–25% or 0–100%
• Patented IR detector uses a sensitive mass flow sensor and a
dual chamber for rapid analysis of IR absorption in a sample
flow
• Unique optical bench design eliminates mechanical chopping
of IR source
• IR bench does not require tuning for maximum signal like
other optical NDIR systems
• Self-diagnostic software installed
• Easy setup and maintenance
• Easy to operate with all user controls accessible from the front
panel
• CE Mark (IR7000 Rack and battery portable)
1.2 Optional Features
4 Teledyne Analytical Instruments, - Rev. 3
NDIR Gas Analyzer Introduction 1
To extend the versatility of the Ir7000 series of analyzers, many
options are available.
• Dual optical bench for simultaneous monitoring of 2 gases
• Oxygen channel (0–25% or 0–100%). The IR7000 series easily
accepts Teledyne analytical Instruments oxygen
electrochemical cell for measuring oxygen levels in the process
gas.
• RS-232 port for control input and data output via a remote
computer
• 4–20ma analog current output either isolated or non-isolated
Teledyne Analytical Instruments., - Rev. 3 5
Introduction 1 IR7000
• Relay outputs. Single pole double throw (SPDT) relays driven
off the status signal, high, and low limit alarms can be installed
for triggering status alarms, indicators, or other customer
supplied peripherals.
• External sample system. The instrument can be supplied with a
sample handling system ensuring safe delivery of conditioned
sample gas to the analyzer.
• Z-Purge system. The split-architecture models can be fitted
with a Z-Purge system for automatic purging of the NEMA-4
enclosure.
1.3 IR Detection
Central to the IR7000 analyzer is the unique patented IR detector. It
incorporates 2 chambers in optical series at the end of a gold-coated
sample cell. The chambers are connected through a tiny orifice. IR is
differentially absorbed in the 2-chambered detector and causes a mass
flow between the chambers. The modulation of the IR signal causes the
chambers to quickly readjust and the flow reverses. A sensitive mass flow
sensor located in the tiny orifice between the 2 chambers senses the flow
in both directions and outputs a signal related to the concentration. A
high-resolution electronic circuit is employed to provide synchronous
detection of the flow sensor’s signal. This circuit allows the IR7000 to
measure gas compositions over a wider range of the infrared spectrum
than conventional photon-based IR analyzers.
1.4 Operator Interface
Except for the split architecture models (Explosion Proof), the
analysis and control sections are housed together in a single compact
metal housing. A NEMA-4 enclosure is used on the IR7000B wall
mountable model.
All operator input and display of process information takes place
from the panel (or on the control section panel for the split architecture
instruments). There are minor differences in the location of some of the
components among the different models within the IR7000 series but each
instrument has the following front panel components:
• Display—vacuum fluorescent with 2 lines of 16 characters.
The display sends data and information to the user about the
process and guides the operator through the calibration and
operation.
6 Teledyne Analytical Instruments, - Rev. 3
NDIR Gas Analyzer Introduction 1
• Input Buttons—4 push buttons are installed on the front panel
and are used to enter data and set operational modes.
• Flowmeter—an integral flowmeter is mounted on the front
panel for monitoring the sample flow through the instrument.
• Power Switch—an off/on switch is mounted on the front panel
for powering up the instrument.
• Sample Pump Switch (IR7000P only)—this switch controls
the operation of the sample pump on portable models.
• Sample Pump Connector (IR7000P only)—a quick
disconnect nylon fitting is mounted on the front panel of
portable models for attaching the sample probe to the
instrument.
.
Teledyne Analytical Instruments., - Rev. 3 7
Operational Theory
2.1 Introduction
The IR7000 is a microprocessor controlled, single beam infrared
analyzer that employs an electronically modulated IR source with no
moving parts.
The analyzer is composed of 2 subsystems:
• Optical Bench
• Electronics
2.2 Optical Bench
At the heart of the IR7000 NDIR Gas Analyzer is the patented dual
chambered balanced detector. The advanced detector design offers higher
sensitivity and selectivity with a greater dynamic range compared to other
IR detectors in the marketplace.
The optical bench is shown in Figure 2-1. It consists of:
• Sample cell
• Detector
• IR source
• Filter cell
• Windows and seals
The sample cell is a gold coated glass tube (metal Tube Optional)
through which the sample gas flows. At one end of the sample cell,
infrared energy is generated by a modulated IR source. The modulation is
achieved electronically by feeding the IR source a 4 Hz square wave
generated by the source control circuit on the main PC board. The
electronic modulation is very stable and eliminates the need for
mechanical choppers and motors routinely used in other IR systems. At
the other end of the optical bench is the detector and filter cell.
NDIR Gas Analyzer Operational Theory 2
Figure 2-1: Optical Bench Components
The detector consists of 2 chambers filled with the gas of interest in
optical series with a sensitive mass flow sensor. The sensor measures a
fluctuating mass flow between the 2 chambers due to a differential in
infrared absorption between the chambers.
The 2 chambers of the detector are of unequal volume, the first
chamber, called the primary chamber, is much smaller than the trailing
chamber, or secondary chamber. A small passageway connects the 2
chambers and contains the mass flow sensor. During assembly at the
factory, both chambers are filled with the gas of interest and due to the
unequal volume, a vastly different optical path length exists between the
chambers.
Initially, with only nitrogen (zero gas) passing through the sample
cell, pulsed IR radiation from the source passes through the cell. Since this
is the zero gas, no differential absorption takes place. At the rear of the
sample cell an IR transparent window (typically sapphire but may be some
other material depending on the application) allows the radiation to pass
into the primary detector chamber. Due to the heteroatomic nature of the
gas contained within the chambers (identical to the gas to be monitored),
IR absorption takes place at a few characteristic wavelengths
corresponding to the most strongly absorbed lines for that particular gas in
the IR spectrum. The remaining radiation passes through to the secondary
chamber.
The secondary chamber has a much greater path length and therefore
additional absorption takes place but at different energies. Due to the
longer residence time of the optical beam in this chamber, absorption
occurs at weaker absorption bands in the IR and accounts for the less
intense absorption relative to the primary chamber. The remaining
unabsorbed energy is eventually dissipated.
Essentially, the front chamber absorbs IR differentially at specific
wavelengths characteristic of the gas of interest within the detector
Teledyne Analytical Instruments., - Rev. 3 9
Operational Theory 2 IR7000
chamber while the rear chamber absorbs radiation at primarily weaker
absorption bands. The absorption causes the gas to heat up and the
differential nature of the absorption process causes the front chamber to
heat up more than the rear chamber. Since the chambers are charged with
gas, the pressure in the primary chamber becomes higher than in the
secondary chamber. This pressure differential causes a net flow of gas
from the primary chamber to the secondary chamber through a tiny orifice
connecting the 2 chambers. The gas cools in quick order and the flow
reverses until the pressures are once again equal.
A mass flow sensor is placed in the orifice between the 2 chambers
and senses the mass transport between them. It is designed in such a
manner as to be able to sense minute flows in either direction. The sensor
produces a signal resulting from an electronic imbalance each time mass
flow is detected (in either direction) through the orifice. The signal is
passed along to a preamplifier and then to a voltage to frequency converter
for enhanced signal processing. The microcontroller retains this
information as a zero gas reading for calibration and offset in real
measurements.
When the process is repeated and a span gas is introduced into the
sample cell, a slightly different condition exists. Now IR absorption takes
place within the sample cell. Less energy is received at the detector. But
since the primary chamber is smaller than the secondary chamber and
differential absorption takes place at predominately strongly absorbing
wavelengths within the primary chamber, the difference in energy of the
gas in the primary chamber is less than when there is no IR absorption in
the sample cell. The energy of the gas in the secondary chamber is also
less but the change is not as dramatic. Hence the patented balanced design
detector produces a different signal when an IR absorbing gas is
introduced in the sample cell. The resulting signal is inversely related to
the concentration of the gas of interest in the sample cell.
Between the IR window and the detector is the filter cell. Depending
on the nature of the sample gas, some applications could experience
interference in the absorption band spectra. For instance, both CO and CO
absorb at wavelengths in the IR very close to each other. The presence of
CO2 could produce a measurement error in a system designed to detect
CO. The filter cell is a sealed volume of gas specifically designed to
“comb out” the offending absorption line or lines before the radiation
reaches the detector. The filter cell in some cases acts as a thermal barrier
to keep the detector from experiencing sudden temperature fluctuations.
2
10 Teledyne Analytical Instruments., - Rev. 3
NDIR Gas Analyzer Operational Theory 2
2.3 Electronics
The IR7000 uses a sophisticated microprocessor to control the signal
processing, I/O, and display functions within the analyzer. Custom
EPROMs are installed with permanently stored data and routines specific
to the customer’s application. Depending on what options are installed, 2
or more PCB’s are used in the electronic subsystem. Figure 2-2 shows the
location of the boards in the portable model. Other models are similar but
mount the boards differently.
2.3.1 Power Supply
This unit is externally powered by either 120 or 230 VAC. Fuses are
located on the back panel for circuit protection.
Figure 2-2: PC Board Identification and Location
Teledyne Analytical Instruments., - Rev. 3 11
Operational Theory 2 IR7000
2.3.3 Main Board
In effect, the main board imports an analog signal from the
preamplifier and outputs a digital signal. A lot of signal conditioning and
processing is performed along the way. Major functions of this board
include:
• Amplification
The signal from the detector is amplified
• Filter
The analog signal is filtered and conditioned
• A to D Converter
The analog signal is digitized using a voltage to frequency
converter
• Microprocessor
Encodes both the amplitude and phase of the digital signal
Counts, integrates, and stores the signal
Handles input and output to and from the main board
• Linearizer
Scales and linearizes the signal using data and algorithms
permanently stored in the microprocessor
• Filter
De-spikes, pre-filters and filters the signal again with a
filter rate chosen by the operator
The main board receives the raw signal from the detector and
amplifies it. In the analog circuit portion of the main board, the signal is
filtered to remove any electrical interference before passing it along to the
digital section as a relatively clean sine wave of several volts.
The sine wave is digitized using an onboard voltage to frequency
converter. In this process, both the amplitude and phase of the digital
signal are encoded and integrated. The microprocessor counts the digital
pulses and linearizes it using a 7th order polynomial whose coefficients
were determined at the factory based on the particular detector.
12 Teledyne Analytical Instruments., - Rev. 3
NDIR Gas Analyzer Operational Theory 2
The data is linearized over the entire instrument range. This
linearization is inherently more accurate than the conventional process of
segmenting and optimizing the data over a narrow range.
Before being sent to the read out display or output as a voltage, the
result is de-spiked and filtered then scaled for the appropriate chart output
range. Filtering uses a selectable algorithm to damp sudden value
changes. The amount of filtering applied is determined by the operator and
generally depends on the process. Large filter values yield a
correspondingly lower instrument response but higher sensitivity.
The de-spiking filter is a software routine used to clean up the signal.
Essentially it looks at the last 5 instrument readings and discards a reading
if it varies significantly over the average. A “rolling average” method of
filtering is also applied through the software. This filtering process
depends on the filter value set by the user. Increasing the filter number
gives more weight to the last entry into the instrument reading buffer,
hence the “rolling average” is influenced to a greater degree by the last
input.
Figure 2-3 is a system block diagram which shows the functional
relationship between the electronics and the optical bench.
Figure 2-3: System Block Diagram
Teledyne Analytical Instruments., - Rev. 3 13
Operational Theory 2 IR7000
During calibration, the microcontroller on the main board stores
information regarding zero and full span values. Specifically, the
microprocessor takes a series of consecutive readings and calculates the
difference between pairs of consecutive readings. The embedded software
analyzes the resulting differences and tests for discrepancies in the result.
The microprocessor uses this information to test for drift during
calibration.
The absolute difference between a true zero and 100% span gas is
determined at the factory and permanently stored in memory. The
software compares this value with collected data during a calibration or
measurement to determine the validity of the reading. If the calibration or
sample gas measurement falls outside a predetermined range based on the
known good values in memory, error routines are called and signals are
sent to the display board to generate appropriate messages. See Section 5
Calibration for more information.
2.3.4 Display
The display contains the 2-line 16 character vacuum fluorescent
display on the front panel. Signals are transferred to and from the main
board via a ribbon cable.
2.3.5 I/O Board
The standard I/O board is responsible for taking a analog signal from
the main board and converting it to a 0–1, 0–5 or 0–10 V analog output.
An optional 4–20 mA isolated current ouput may be installed depending
on the options selected by the customer. See Section 3.7.1.
2.4 Sample System
If a sample system is not provided by LSC, the customer will be
responsible for providing a suitable sample system. A custom sample
system can be designed and fabricated by LSC based on the particular
application. Contact Teledyne Analytical Instruments for details.
In order to achieve maximum results from the analyzer, some
consideration must be given to the sample system design. The sample
system is responsible for supplying properly conditioned sample and
calibration gases to the analyzer at a pressure and flow rate commensurate
with the analyzer. The sample system provided by the customer must be
capable of delivering clean and moisture free (non-condensing) sample to
14 Teledyne Analytical Instruments., - Rev. 3
NDIR Gas Analyzer Operational Theory 2
the instrument with a flow rate between 0.2–2.0 liters per minute (2.0 to
5.0 liters per minute for low level optical bench) at 5 psig or less. For
samples greater than 5 psig contact factory. The sample temperature must
be in the range of -10 to 50°C (14–122)°F.
WARNING: The maximum rated pressure of the sample cell is 5 psig.
Exceeding this pressure at any time may cause the sample cell to
fail. This could result in harmful release of sample gas.
The following are items to be provided by the customer:
• Calibration gases
• Nitrogen (N
) for zero calibration
2
• Span calibration gas
Use a span gas with a concentration of the gas of
interest greater than 50% of the largest desired
measurement. The span gas should be between 10%
and 100% of the instrument’s full scale, preferably
around 80%. For example, if the largest expected
reading is 3000 ppm, then the calibration gas should be
at least 1500 ppm.
The balance of the span gas should be N2.
If the instrument has a dual optical bench (Model
IR7000B or IR7000D), the span gas must contain
calibration values for both species being measured.
If an optional oxygen (O2) sensor is installed, the span
gas must contain a calibration value for O2. If the 0–
25% O
sensor is installed, use a calibration gas
2
containing 20% O2.
• Pressure regulator, flow adjustment valves, tubing and fittings
for delivering properly conditioned sample gas to the
instrument. The sample gas pressure must be less than 5
psig. For pressures above 5 psig contact factory.
• Pressure regulator, flow adjustment valves, tubing and fittings
for delivering calibration (zero and span) gas to the instrument.
• If the automatic calibration feature is to be used, the customer
must also supply 2 solenoid valves. The split architecture
versions of this instrument are capable of handling 3 solenoid
valves. Refer to Section 3 Installation and Setup for details
regarding the installation of these components.
• The sample gas should be vented to atmospheric pressure. If the
Teledyne Analytical Instruments., - Rev. 3 15
Operational Theory 2 IR7000
sample gas is to be returned to the process or flare, suitable back
pressure controls should be employed to ensure the analyzer vents
at a constant pressure.
2.5 Internal Gas Handling System
The gas handling system inside the analyzer is similar in principle for
all models. The following information describes the internal gas handling
system for the IR7000 model. Variations for other models will be noted.
Figure 2-4 is a diagram of the internal components and plumbing for
directing calibration or sample gas through the analyzer.
Figure 2-4: Sample Path Through Analyzer – Sta ndard Model
Either sample or calibration gas is delivered under pressure to the
analyzer by the customer or LSC supplied sample system. The gas enters
the analyzer and passes through a 0.3-micron disposable filter to remove
any particulate matter. If an O2 channel has been incorporated, the O
2
sensor is installed in series with the sample cell. The gas passes first
through the O2 sensor and then through the sample cell and out to the
sample return.
In the portable model, a 12V DC mini-pump is installed between the
disposable filter and the sample cell. Otherwise the internal plumbing is
the same.
The internal gas handling systems installed in the split-architecture
and explosion proof models vary according to the specific application. In
general, the plumbing is the same as the standard models with the
following exceptions:
• Metal tubing and fittings replace Teflon lined PVC tubing
16 Teledyne Analytical Instruments., - Rev. 3
NDIR Gas Analyzer Operational Theory 2
• Stainless steel, brass or copper fittings are installed for mating
to the customer’s sample system or throughout the system for a
LSC supplied sample system.
• A different filter and a filter housing is used
NOTE: Because these models are often supplied for custom applications,
please check the front of this manual for any included Addendum
which will describe features, notes and warnings that specifically
apply to your instrument.
Teledyne Analytical Instruments., - Rev. 3 17
Installation
3.1 Overview
Installing the Model ir7000 consists of:
• Unpacking and Inspection
• Mounting
• Gas Connections
• Electrical Connections
• Calibrating the System
3.2 Unpacking and Installation
The analyzer is shipped ready for installation. You should have
received a single carton containing the analyzer and power cord (except
230 VAC versions). If you have ordered an instrument with the optional
O2 sensor channel, the electrochemical cell will have been installed at the
factory.
Carefully unpack the instrument and inspect it for any damage or
missing components. Signs of damage would include dents, scratches,
broken glass inside the casing etc. Check that you have received the power
cord or battery charger for the portable model. Contact the shipper
immediately to report shipping damage. Contact the factory for missing
parts.
3.3 Mounting the Analyzer
The ir7000 series of analyzers are designed to be used indoors and in
a general-purpose area. The split-architecture models (explosion proof) are
designed to have the analysis unit operate in a hazardous environment
with the control unit remotely located in a general-purpose area.
The instrument must be kept dry and protected from:
• Direct sunlight
• Direct air currents which could affect the temperature of the
sensors
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