Endress+Hauser SS500 Instruction Manual

P/N 4900002285 rev B
SS500/SS2000
Single Channel Gas Analyzer
Hardware Installation
and Maintenance Manual

Products of
4333 W Sam Houston Pkwy N, Suite 100
Houston, TX 77043-1223
Tel: [phone]
Fax: [phone]
www.spectrasensors.com
Copyright © 2020 SpectraSensors, Inc. No part of this manual may be reproduced in
whole or in part without the express written permission of SpectraSensors, Inc.
SpectraSensors reserves the right to change product design and specifications at any
time without prior notice.
SS500/SS2000
Single Channel
Gas Analyzer
Hardware Installation and
Maintenance Manual
Use this manual with the
Firmware Operator’s Manual

Revision History
Revision Engineering Order Date
A EO17516 June 7, 2018
B ECR18150 March 26, 2020

Hardware Installation and Maintenance Manual i
TABLE OF CONTENTS
1: Introduction
Who Should Read This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
How to Use This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Conventions used in this manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
General Warnings and Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Safety warning label. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Equipment labels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Instructional symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
SpectraSensors Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
How the Analyzers Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Wavelength Modulation Spectroscopy (WMS) Signal Detection . . . . . . . . . . . 1-7
Getting Familiar with the Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Fuses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
2: Safety
Potential Risks Affecting Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Mitigating risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
To mitigate electrocution hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
To mitigate exposure to process gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Explosion hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
3: Installation
What Should be Included in the Shipping Box . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Inspecting the Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Installing the Analyzer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Hardware and tools for installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Lifting/carrying the analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2
Mounting the analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
To mount the analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Connecting Electrical Power to the Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Protective chassis and ground connections . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
To connect electrical power to the analyzer. . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Connecting the Output Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
To connect the output signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Changing the 4-20 mA Current Loop Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
To change the 4-20 mA board from source to sink . . . . . . . . . . . . . . . . . . . . 3-9
Calibrating the analog output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Testing and adjusting the 4-20 mA zero and span . . . . . . . . . . . . . . . . . . . 3-11
Connecting the Gas Lines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
To connect the sample supply line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
To connect the sample return . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13
Conditioning the SCS Tubing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14
4: Sample Conditioning System (SCS)
About the SCS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Checking the SCS Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
To perform SCS installation checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
SCS Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
To prepare for SCS startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
To start up the field pressure reducing station. . . . . . . . . . . . . . . . . . . . . . . 4-5

SS500/SS2000 Analyzer
ii 4900002285 rev. B 3-25-20
Starting up the full-featured sample system . . . . . . . . . . . . . . . . . . . . . . . . 4-5
To start up the sample bypass stream on process sample. . . . . . . . . . . . . . . 4-6
To start up the analyzer on process sample . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Starting up the Simplified Sample System . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
To start up the simplified sample system . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Shutting Down the SCS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
To isolate the analyzer for short-term shutdown
(full-featured sample system) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
To isolate the analyzer for long-term shutdown
(full-featured sample system) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
To isolate the analyzer for shutdown (simplified sample system) . . . . . . . . . 4-11
Appendix A: Specifications
Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-13
Appendix B: Maintaining & Troubleshooting
Gas Leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
To keep the sampling lines clean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Excessive Sampling Gas Temperatures and Pressures . . . . . . . . . . . . . . . . . . . . B-2
Electrical Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Powering Down the Analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
To power down the analyzer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Peak Tracking Reset Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
Mirror Cleaning/Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
To determine the type of cell mirror . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
Tools and supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-5
To clean the glass mirrors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-5
To replace the stainless steel mirror. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-7
Pressure Sensor Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-8
Tools and materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-8
To replace the pressure sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-9
To unlock/set the flow meter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-13
Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-13
To replace the membrane separator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-14
To replace the rotameter (SS500 simplified sample system only) . . . . . . . . B-15
Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-16
Periodic SCS Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-17
To perform regular SCS status check . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-18
To check filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-18
Instrument Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-19
Service Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-22
Before contacting Technical Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-22
Service repair order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-22
Renewity returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-23
Packing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-23
To purge the analyzer for shipment or relocation . . . . . . . . . . . . . . . . . . . . B-23
To prepare the analyzer for shipment or storage . . . . . . . . . . . . . . . . . . . . B-23
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-24
Disclaimers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-24
Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-24
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index-1

Hardware Installation and Maintenance Manual iii
LIST OF FIGURES
Figure 1–1. Schematic of typical tunable diode laser absorption
spectrometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
Figure 1–2. Typical raw signal from a tunable diode laser absorption
spectrometer with and without mirror contamination . . . . . . . . . . 1-6
Figure 1–3. Typical normalized absorption
signal from a tunable diode laser absorption spectrometer. . . . . . . 1-6
Figure 1–4. Typical normalized 2f signal; species concentration is
proportional to the peak height . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Figure 1–5. Analyzer Overview (SS500/SS2000 pictured). . . . . . . . . . . . . . . . 1-8
Figure 1–6. Electronics control board (AC) for single-channel systems
(SS500/SS2000) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Figure 1–7. Electronics control board (DC) for single-channel systems
(SS500/SS2000) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Figure 3–1. Chassis ground location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Figure 3–2. Internal view of electronics enclosure (SS500/SS2000). . . . . . . . . 3-6
Figure 3–3. AC and DC connection terminal blocks in electronics enclosure. . . . 3-7
Figure 3–4. Mating terminal block (TB2) in electronics enclosure for
connecting signal cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Figure 3–5. 4-20 mA output board. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Figure 4–1. SS500/SS2000 full-featured, single-channel SCS on a panel . . . . . 4-3
Figure 4–2. SS500 with simplified, single-channel SCS on a panel . . . . . . . . . . 4-3
Figure 4–3. Starting up the SS500 simplified sample system . . . . . . . . . . . . . 4-7
Figure 4–4. Bypass flow diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Figure 4–5. Shutting of sample supply shut-off valve . . . . . . . . . . . . . . . . . . 4-12
Figure A–1. SS500/SS2000 0.8 m cell (moisture) outline and
mounting dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3
Figure A–2. SS500/SS2000 0.1 m cell (carbon dioxide) outline and
mounting dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4
Figure A–3. Drawing of analyzer with simplified single-channel sample
system (SS500) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
Figure A–4. Drawing of single-channel analyzer with simplified sample
system in 24” x 24” enclosure (SS500) . . . . . . . . . . . . . . . . . . . . A-6
Figure A–5. Drawing of analyzer with full-featured single-channel sample
system on a panel (SS500/SS2000) . . . . . . . . . . . . . . . . . . . . . . A-7
Figure A–6. Drawing of analyzer with full-featured single-channel sample
system in 24” x 24” enclosure (SS500/SS2000) . . . . . . . . . . . . . . A-8
Figure A–7. Drawing of analyzer with full-featured sample system in
30” x 30” enclosure with heat trace power (SS500/SS2000) . . . . . A-9
Figure A–8. Electrical schematic for SS500/SS2000 . . . . . . . . . . . . . . . . . . . A-10
Figure A–9. Interconnect diagram for simplified single-channel system
(SS500). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-11
Figure A–10. Interconnect diagram for full-featured single-channel system
(SS500/SS2000) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-12

SS500/SS2000 Analyzer
iv 4900002285 rev. B 3-25-20
Figure B–1. Measurement cell types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
Figure B–2. Stainless steel mirror marking . . . . . . . . . . . . . . . . . . . . . . . . . . B-4
Figure B–3. Stainless steel mirror - mirror side up . . . . . . . . . . . . . . . . . . . . . B-8
Figure B–4. SS500/SS2000 analyzer component locations . . . . . . . . . . . . . . . B-9
Figure B–5. Removed measurement cell with pressure sensor face up . . . . . . B-10
Figure B–6. Removing the old pressure sensor . . . . . . . . . . . . . . . . . . . . . . B-10
Figure B–7. Removing excess seal tape from flange . . . . . . . . . . . . . . . . . . . B-11
Figure B–8. Replacing seal tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-11
Figure B–9. Replacing pressure sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-12
Figure B–10. Newly installed pressure sensor positioning . . . . . . . . . . . . . . . . B-12
Figure B–11. Setting/locking the needle valve . . . . . . . . . . . . . . . . . . . . . . . . B-14
Figure B–12. Inspecting the membrane separator filter . . . . . . . . . . . . . . . . . B-15
Figure B–13. Disconnecting the rotameter . . . . . . . . . . . . . . . . . . . . . . . . . . B-16
Figure B–14. Stabilizing the rotameter for removal . . . . . . . . . . . . . . . . . . . . B-16

Hardware Installation and Maintenance Manual v
LIST OF TABLES
Table 1–1. Fuse specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Table 3–1. Output signal connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Table A–1. SS500/SS2000 analyzer specifications . . . . . . . . . . . . . . . . . . . . A-1
Table A–2. SS500/SS2000 sample conditioning system specifications . . . . . . . A-2
Table A–3. Replacement parts for SS500/SS2000. . . . . . . . . . . . . . . . . . . . A-13
Table B–1. Potential instrument problems and solutions . . . . . . . . . . . . . . . B-19

SS500/SS2000 Analyzer
vi 4900002285 rev. B 3-25-20
THIS PAGE INTENTIONALLY LEFT BLANK

Hardware Installation and Maintenance Manual 1–1
1 - INTRODUCTION
SpectraSensors’ SS500/SS2000 products are high-speed, diode-laser based
extractive analyzers designed for extremely reliable monitoring of moisture
and carbon dioxide in natural gas applications. To ensure that the analyzer
performs as specified, it is important to closely review the installation and
operation sections of this manual. This manual contains a comprehensive
overview of the SS500/SS2000 analyzer and step-by-step instructions on:
•Getting familiar with the analyzer
•Installing the analyzer and sample conditioning system (SCS)
•Maintaining and troubleshooting the system
For instruction on operating the analyzer through firmware programming,
please consult the Firmware Operations Manual.
Who Should Read This Manual
This manual should be read and referenced by anyone installing, operating or
having direct contact with the analyzer.
How to Use This Manual
Take a moment to familiarize yourself with this manual by reading the Table
of Contents.
There are a number of options and accessories available for the SS500/SS2000
analyzers. This manual has been written to address the most common options
and accessories. Images, tables and charts are included to provide a better
understanding of the analyzer and its functions. Special symbols are also used
to provide the user with key information regarding the system configuration
and/or operation. Pay close attention to this information.
Conventions used in this manual
In addition to the symbols and instructional information, use “hot links” to
quickly navigate between different sections. These links include table, figure
and section references and are identified by a pointing finger cursor when
rolling over the text. Click on the link to navigate to the reference.
General Warnings and Cautions
Instructional icons are provided in this manual to alert the user of potential
hazards, important information and valuable tips. Following are the symbols
and associated warning and caution types to observe when servicing the
analyzer. Some of these symbols are provided for instructional purposes only
and are not labeled on the system.

SS500/SS2000 Analyzer
1–2 4900002285 rev. B 3-25-20
Safety warning label
The warning label shown below will be affixed to the front side of all analyzer
enclosures that contain sample gas.
Hazards may vary by stream composition. One or more of the following
conditions may apply.
Equipment labels
Flammable. Gases used in the processing of this analyzer may
be extremely flammable. Any work in a hazardous area must be
carefully controlled to avoid creating any possible ignition sources
(e.g., heat, arching, sparking, etc.).
Toxins. SpectraSensors analyzers measure a variety of gases,
including high-level H2S. Follow all safety protocols governing
toxic gases and potential leaks.
Inhalation. Inhaling toxic gases or fumes may cause physical
damage or death.
Technicians are expected to follow all safety protocols established
by the customer that are necessary for servicing or operating the
analyzer. This may include, but is not limited to, lockout/tag-out
procedures, toxic gas monitoring protocols, PPE requirements,
hot work permits and other precautions that address safety
concerns related to performing service or operation on process
equipment located in hazardous areas.
Warning statement for hazardous voltage. Contact may cause
electric shock or burn. Turn off and lock out system before
servicing.

Introduction
Hardware Installation and Maintenance Manual 1–3
Instructional symbols
Failure to follow all directions may result in damage or
malfunction of the analyzer.
Maximum voltage and current specifications for the fuse closest
to label.
PROTECTIVE EARTH GROUND - Symbol indicates the
connection point of the ground wire from the main power source.
INVISIBLE LASER RADIATION - Avoid
exposure to beam. Class 3b Radiation Product.
Refer servicing to the manufacturer or qualified
personnel.
Removing label from measurement cell optical
head will void analyzer warranty.
General notes and important information concerning the
installation and operation of the analyzer.
Failure to follow all directions may result in fire.
INVISIBLE LASER RADIATION - Avoid exposure to beam.
Class 3b Radiation Product. Refer servicing to the manufacturer-
qualified personnel.
CAUTION
CLASS 3B INVISIBLE LASER
RADIATION WHEN OPEN
AVOID EXPOSURE TO THE BEAM

SS500/SS2000 Analyzer
1–4 4900002285 rev. B 3-25-20
SpectraSensors Overview
SpectraSensors, Inc. is a leading manufacturer of advanced electro-optic gas
analyzers. Headquartered in Houston, Texas, SpectraSensors was incorporated
in 1999 as a spin-off of the NASA/Caltech Jet Propulsion Laboratory (JPL) for
the purpose of commercializing space-proven measurement technologies
initially developed at JPL. SpectraSensors was acquired by the Endress +
Hauser Group in 2012.
How the Analyzers Work
The SS500/SS2000 analyzers employ tunable diode laser absorption
spectroscopy (TDLAS) to measure the concentration of contaminants such as
moisture in a background of natural gas. Absorption spectroscopy is a widely
used technique for sensitive trace species detection. Because the measurement
is made in the volume of the gas, the response is much faster, more accurate
and significantly more reliable than traditional surface-based sensors that are
subject to surface contamination.
In its simplest form, a diode laser absorption spectrometer consists of a sample
cell with a mirror at one end, and a mirror or window at the opposite end,
through which the laser beam can pass. Refer to Figure 1–1. The laser beam
enters the cell and reflects off the mirror(s) making one or more trips through
the sample gas and eventually exiting the cell where the remaining beam
intensity is measured by a detector. Sample gas flows continuously through the
sample cell ensuring rapid and continuous measurements.
Failure to follow all directions may result in damage or
malfunction of the analyzer.
Maximum voltage and current specifications for fuses.

Introduction
Hardware Installation and Maintenance Manual 1–5
Due to their inherent structure, the molecules in the sample gas each have
characteristic natural frequencies (or resonances). When the output of the
laser is tuned to one of those natural frequencies, the molecules with that
particular resonance will absorb energy from the incident beam. That is, as the
beam of incident intensity, I0(),passes through the sample, attenuation occurs
via absorption by the measured gas with absorption cross section ().
According to the Beer-Lambert absorption law, the intensity remaining, I(), as
measured by the detector at the end of the beam path of length [l] (cell length
x number of passes), is given by
-()ꞏnꞏl(1)
where nrepresents the gas density. Thus, the ratio of the absorption measured
when the laser is tuned on-resonance versus off-resonance is directly
proportional to the number of molecules of that particular species in the beam
path, or
(2)
Figure 1–2 shows the typical raw data from a TDL absorption spectrometer
scan including the incident laser intensity, I0(),and the transmitted intensity,
I(), for a clean system and one with contaminated mirrors (shown to illustrate
the system’s relative insensitivity to mirror contamination). The positive slope
OPTICAL HEAD
DETECTOR
WINDOW
INLET
FAR MIRROR
TEC
LASER
OUTLET
PRESSURE
SENSOR
0.8 m Measurement Cell
Figure 1–1 Schematic of typical tunable diode laser
absorption spectrometer
I I0e=

SS500/SS2000 Analyzer
1–6 4900002285 rev. B 3-25-20
of raw data results from ramping the current to tune the laser, which not only
increases the wavelength with current, but also causes the corresponding
output power to increase. By normalizing the signal by the incident intensity,
any laser output fluctuations are canceled, and a typical, yet more pronounced,
absorption profile results. Refer to Figure 1–3.
3.0
2.5
2.0
1.5
1.0
0.5
Incident Energy I0()
Raw Signal, I()
Raw Signal, I()
(Contaminated Mirrors)
Wavelength [a.u.]
Signal [a.u.]
0.0
Figure 1–2 Typical raw signal from a tunable
diode laser absorption spectrometer with and
without mirror contamination
1.0
0.99
0.98
0.97
0.96
0.95
Normalized Absorption Signal
Wavelength [a.u.]
Signal [a.u.]
Figure 1–3 Typical normalized absorption
signal from a tunable diode laser absorption spectrometer

Introduction
Hardware Installation and Maintenance Manual 1–7
Note that contamination of the mirrors results solely in lower overall signal.
However, by tuning the laser off-resonance as well as on-resonance and
normalizing the data, the technique self calibrates every scan resulting in
measurements that are unaffected by mirror contamination.
Wavelength Modulation Spectroscopy (WMS) Signal Detection
SpectraSensors takes the fundamental absorption spectroscopy concept a step
further by using a sophisticated signal detection technique called wavelength
modulation spectroscopy (WMS). When employing WMS, the laser drive
current is modulated with a kHz sine wave as the laser is rapidly tuned. A lock-
in amplifier is then used to detect the harmonic component of the signal that
is at twice the modulation frequency (2f), as shown in Figure 1–4. This phase-
sensitive detection enables the filtering of low-frequency noise caused by
temperature and/or pressure fluctuations, low-frequency noise in the laser
beam or thermal noise in the detector.
With the resulting low-noise signal and use of fast post-processing algorithms,
reliable parts per million (ppm) or parts per billion (ppb) detection levels are
possible (depending on target and background species) at real-time response
rates (on the order of 1 second).
All SpectraSensors TDLAS gas analyzers employ the same design and hardware
platform. Measuring different trace gases in various mixed hydrocarbon
background streams is accomplished by selecting a laser wavelength that
provides the least amount of sensitivity to background stream variations.
Normalized
2fSignal
Wavelength [a.u.]
Signal [a.u.]
Figure 1–4 Typical normalized 2f signal; species
concentration is proportional to the peak height

SS500/SS2000 Analyzer
1–8 4900002285 rev. B 3-25-20
Getting Familiar with the Analyzer
The SS500 and SS2000 are single-channel analyzers designed to continuously
measure the moisture content in natural gas pipelines. The SS2000 offers
higher measurement performance in those applications, and its single
measurement channel can also be configured to monitor CO2 levels in natural
gas pipelines, or to measure the moisture content in CO2 pipelines. For
performance specifications, refer to Table A–1 and Table A–2.
SpectraSensors’ SS500/SS2000 analyzers are typically comprised of a single
electronics enclosure and associated measurement cell(s). Refer to Appendix A
for the system drawings. On the front panel of the analyzer, the keypad and
LCD display serve as the user interface to each analyzer. The analyzer control
electronics drive the laser, collect the signal, analyze the spectra and provide
measurement output signals. Refer to Figure 1–5.
Power is connected to the analyzer from an external power source through the
bottom of the enclosure. The measurement cell along with flow devices to
control flow and pressure for the measurement cell and the bypass loop may
be mounted on a panel alongside the electronics enclosure.
Fuses
Inside the SS500/SS2000 analyzer electronics enclosure is the electronics
assembly. Fuses are located on the electronics control board, as shown in
Figure 1–6 and Figure 1–7.
Figure 1–5 Analyzer Overview (SS500/SS2000
pictured)
LCD/KEYPAD
MEASUREMENT
CELL AND LASER
POWER CONNECTION
ELECTRONICS
ENCLOSURE

Introduction
Hardware Installation and Maintenance Manual 1–9
If you need to replace a fuse, use only the same type and rating
of fuse as the original as listed in Table 1–1.
Table 1–1 Fuse specifications
DWG Ref. Volt-
age Description Rating
Figure 1–6 F1
120 VAC Miniature Fuse, 5 x 20 mm, Time Delay 250VAC/0.8A
240 VAC Miniature Fuse, 5 x 20 mm, Time Delay 250VAC/0.5A
Figure 1–7 F2
12 VDC Miniature Fuse, 5 x 20 mm, Time Delay 250VAC/3.15A
24 VDC Miniature Fuse, 5 x 20 mm, Time Delay 250VAC/1.6A

SS500/SS2000 Analyzer
1–10 4900002285 rev. B 3-25-20
Figure 1–6 Electronics control board (AC) for single-
channel systems (SS500/SS2000)
TEMPERATURE
CONTROL BOARD
4-20 mA CURRENT LOOP
BOARD (STACKED)
FUSE
(F1)
4-20 mA & SERIAL SIGNAL
CONNECTIONS
ASSIGNABLE
ALARM RELAY
GENERAL FAULT
ALARM RELAY
NO
COMMON
NC
LASER
DRIVER
BOARD
BACKPLANE
POWER
SUPPLY
CUSTOMER
GROUND
PROTECTIVE
GROUND
EARTH
GROUND