Endress+Hauser SpectraSensors SS2100 User manual

Products Solutions Services
Operating Instructions
SS2100 TDLAS Gas Analyzer
BA02281C/66/EN/01.23
70208914

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Endress+Hauser
Operating Instructions SS2100 TDLAS Gas Analyzer
Table of Contents
1Introduction.......................................... 3
1.1 Document function..................................................3
1.2 Designated use.........................................................3
1.3 Symbols used............................................................3
1.4 Standard documentation ........................................5
1.5 Manufacturer address.............................................6
1.6 Glossary ....................................................................6
2Safety..................................................... 8
2.1 Personnel qualifications .........................................8
2.2 Potential risks affecting personnel........................8
2.3 Product safety ..........................................................9
2.4 Workplace safety.................................................. 10
2.5 Operational safety ................................................ 10
2.6 Lifting provisions for the analyzer ..................... 11
3Product description............................ 12
3.1 How Endress+Hauser TDLAS Gas Analyzers
work ....................................................................... 13
3.2 SS2100 TDLAS Gas Analyzer model types......... 16
4Incoming product acceptance and
identification ...................................... 21
4.1 Scope of delivery................................................... 21
4.2 Inspecting the analyzer........................................ 21
4.3 Determining firmware version............................ 21
5Installation ......................................... 22
5.1 Site requirements and installation conditions .. 22
5.2 Hardware and tools for installation ................... 23
5.3 Mounting the analyzer ........................................ 24
5.4 Connecting electrical power ................................ 24
5.5 Connecting the gas lines...................................... 33
6Sample conditioning system ............. 38
6.1 Sample conditioning system overview ............... 38
6.2 Checking the SCS installation ............................. 41
6.3 Starting up the SCS ...............................................42
7Validation for trace moisture (H2O)
or ammonia (NH3) analyzers.............45
7.1 Validation methods ..............................................45
7.2 Permeation tubes for validation of trace H2O
or NH3measurements ..........................................46
7.3 Installing the permeation tube for NH3
systems...................................................................48
7.4 Replacing the permeation tube ...........................49
7.5 Permeation tube storage......................................50
7.6 Using validation gas .............................................50
8SS2100 TDLAS Gas Analyzer
maintenance .......................................51
8.2 Shutting down the SCS .........................................53
8.3 4-20 mA board adjustments................................55
8.4 Mirror maintenance .............................................58
8.5 Replacing a fuse ....................................................62
8.6 Filter maintenance................................................64
8.7 Replacing the pressure sensor.............................65
8.8 Scrubber maintenance for H2S systems..............73
8.9 Replacing the dryer for H2O and NH3systems...76
8.10 Heat trace sleeve bundle ......................................76
9Instrument troubleshooting ..............77
9.1 Warnings and errors.............................................77
9.2 Troubleshooting symptoms .................................79
10 Service..................................................83
10.1 Packing, shipment, and storage ..........................83
10.2 Service ....................................................................84
10.3 Disclaimers ............................................................84
10.4 Warranty................................................................84
11 Technical data and drawings.............85
11.1 SS2100 specifications...........................................85
11.2 Drawings ................................................................88

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SS2100 TDLAS Gas Analyzer Operating Instructions
1Introduction
1.1 Document function
This operating instruction contains information required to install and operate the SS2100 TDLAS Gas Analyzer and
electronics. This manual also provides a components overview and installation requirements for connecting the
SS2100 electronics. It is important to closely review the sections of this manual to ensure the analyzer performs as
specified.
1.2 Designated use
Endress+Hauser’s SS2100 products are high-speed, diode laser-based extractive analyzers designed for extremely
reliable monitoring of very low (trace) to standard concentrations of specific components in a variety of background
gases.
Use of the device for any purpose other than that described poses a threat to the safety of people and of the entire
measuring system and is therefore not permitted. The manufacturer is not liable for damage caused by improper or
non-designated use.
1.2.1 How to use this manual
There are a number of options and accessories available for the SS2100. This manual has been written to address the
most common options and accessories. Images, tables and charts have been included to provide a visual
understanding of the analyzer and its functions. Special symbols are also used to provide the user with key
information regarding the system configuration and operation. Pay close attention to this information.
1.3 Symbols used
1.3.1 Warnings
Structure of Information
Meaning
Causes (/consequences)
Consequences of non-compliance (if applicable)
‣ Corrective action
This symbol alerts you to a dangerous situation. Failure to avoid the dangerous
situation can result in a fatal or serious injury.
Causes (/consequences)
Consequences of non-compliance (if applicable)
‣ Corrective action
This symbol alerts you to a dangerous situation. Failure to avoid this situation
can result in minor or more serious injuries.
Cause/situation
Consequences of non-compliance (if applicable)
‣ Action/note
This symbol alerts you to situations which may result in damage to property.
1.3.2 Safety symbols
Symbol
Description
Hazardous voltage and risk of electric shock.
INVISIBLE LASER RADIATION - Avoid exposure to the beam. Class 3R Radiation Product. Refer servicing to
manufacturer-qualified personnel.

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Operating Instructions SS2100 TDLAS Gas Analyzer
1.3.3 Informational symbols
Symbol
Meaning
Permitted: Procedures, processes or actions that are permitted.
Forbidden: Procedures, processes or actions that are forbidden.
Tip: Indicates additional information.
Reference to documentation
Reference to page
Reference to graphic
Notice or individual step to be observed
1., 2., 3. …
Series of steps
Result of a step
1.3.4 Symbols on this device
Symbol
Description
The warning label 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:
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, arcing, sparking, etc.).
Toxins. Endress+Hauser 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/tagout
procedures, toxic gas monitoring protocols, personal protective equipment (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.
The High Voltage symbol alerts people to the presence of electric potential large enough to cause
injury or damage. In certain industries, high voltage refers to voltage above a certain threshold.
Equipment and conductors that carry high voltage warrant special safety requirements and
procedures. Turn off and lock out system before servicing.
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.
FUNCTIONAL EARTH GROUND —Symbol indicates grounding points intended primarily for
troubleshooting.
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.
CAUTION
CLASS 3B INVISIBLE LA SER
RADIATION WHEN OPEN
AVOID EXPOSURE TO THE BEAM

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SS2100 TDLAS Gas Analyzer Operating Instructions
1.4 Standard documentation
All documentation is available:
•On the USB provided with the analyzer
•Endress+Hauser’s website: www.endress.com
Each analyzer shipped from the factory is packaged with documents specific to the model that was purchased. This
document is an integral part of the complete document package, which also includes:
Part Number
Document Type
Description
TI01667C
SS2100 Technical
Information
Planning aid for your device. This document contains information for the analyzer
including system design with sample conditioning components and inlet/outlet
points, certificates and approvals, and product technical data.
XA02750C
SS2100 Safety
Instructions
Requirements for installing or operating the SS2100 TDLAS Gas Analyzer related
to personnel or equipment safety.
XA02751C
2-pack and 3-pack
Safety Instructions
Safety Instructions for the SS2100 2-pack and 3-pack TDLAS Gas Analyzer for
multiple analytes.
GP01177C
Description of Device
Parameters (FS 5.16)
Provides the user with an overview of the FS 5.16 firmware functionality.
GP01180C
Description of Device
Parameters (NS 5.14)
Provides the user with an overview of the NS 5.14 firmware functionality.
GP01181C
Description of Device
Parameters (HC12)
Provides the user with an overview of the PP2f (HC12) firmware functionality.
For additional instruction manuals, please refer to the following:
•For custom orders, go to the Endress+Hauser website for the list of local sales channels who can provide the
requested order-specific documentation:
https://endress.com/contact
or
https://addresses.endress.com/
•For standard orders, go to the Endress+Hauser website to download the published documentation:
www.endress.com

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Operating Instructions SS2100 TDLAS Gas Analyzer
1.5 Manufacturer address
Endress+Hauser
11027 Arrow Route
Rancho Cucamonga, CA 91730
United States
www.endress.com
1.6 Glossary
Term
Description
2-wire
In a 2-wire current loop, the transmitter, DC power supply, and PLC are connected in series. Not only are
the 2 wires providing power for the transmitter, but they are also the signal lines.
4-20 mA
An analog current loop for process control applications, used to carry signals from process
instrumentation to PID controllers, SCADA systems, and programmable logic controllers (PLCs). They are
also used to transmit controller outputs to the modulating field devices such as control valves.
Acceptance testing
A test conducted to determine if the requirements of a specification or contract are met. It may involve
chemical tests, physical tests, or performance tests.
Analog to digital
converter (ADC)
A system that converts an analog signal, into a digital signal so that it can be read and processed by a
microcontroller.
Analyte
A substance whose chemical constituents are being identified and measured.
Bend radius (BR)
The minimum radius one can bend a pipe, tube, sheet, cable or hose without kinking it, damaging it, or
shortening its life.
Calibration
A process in which a known amount of various gases are used to produce an accurate analyte reading.
Capacitance
The ratio of the change in electric charge of a system to the corresponding change in its electric potential.
Connectorization
An electrical connector for terminating a shielded cable and connecting the cable to regularly arranged
contact pins.
CW laser
Continuous wave laser, as opposed to a pulsed laser, have an uninterrupted beam that gives a nominally
constant output over a set interval.
Density
The mass of a substance is its mass per unit volume.
Differential
TDLAS technology based on subtracting one spectrum from another. A dry spectrum, the response from a
sample when the analyte of interest has been completely removed, is subtracted from the wet spectrum,
the response from the sample when the analyte is present. The remainder is a spectrum of the pure
analyte.
Divert valve
A divert valve is located between a chromatograph (gas or liquid) and the source of a mass spectrometer,
and acts to either allow the flow from the chromatograph to enter the source or not.
Fermentation
The chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving
effervescence and the giving off of heat.
HART
communication
protocol
A hybrid analog+digital industrial automation open protocol. Its most notable advantage is that it can
communicate over legacy 4–20 mA analog instrumentation current loops, sharing the pair of wires used
by the analog-only host systems.
Heat sink
A passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a
fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing
regulation of the device's temperature.
Infrared (IR)
Electromagnetic Radiation (EMR) with wavelengths longer than those of visible light.
Input/output (I/O)
The communication between an information processing system, such as a computer, and the outside
world, possibly a human or another information processing system. Inputs are the signals or data
received by the system and outputs are the signals or data sent from it.
Ion
Atomic, molecular, or radical species with a non-zero net electric charge.
Laser
A device that emits light through a process of optical amplification based on the stimulated emission of
electromagnetic radiation.

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SS2100 TDLAS Gas Analyzer Operating Instructions
Term
Description
Lockout/tagout
Proper lockout/tagout (LOTO) practices and procedures safeguard workers from hazardous energy
releases. OSHA's Lockout/Tagout Fact sheet →describes the practices and procedures necessary to
disable machinery or equipment to prevent hazardous energy release. The OSHA standard for The
Control of Hazardous Energy (Lockout/Tagout) (29 CFR 1910.147 →) for general industry outlines
measures for controlling different types of hazardous energy. The LOTO standard establishes the
employer's responsibility to protect workers from hazardous energy. Employers are also required to train
each worker to ensure that they know, understand, and are able to follow the applicable provisions of the
hazardous energy control procedures.
Modbus
Data communications protocol originally published by Modicon in 1979 for use with its programmable
logic controllers.
Modbus TCP/IP
(also Modbus-TCP)
The Modbus RTU protocol with a TCP interface that runs on Ethernet. The Modbus messaging structure is
the application protocol that defines the rules for organizing and interpreting the data independent of
the data transmission medium.
Modbus RTU over
RS485
The Modbus protocol used on top of a serial line with an RS-485 physical interface.
Non-differential
TDLAS technology in which TDL spectroscopy measurements are made directly from the sample.
Permeation tube
(perm tube)
A sealed cylinder of a permeable material with an analyte of interest inside. The analyte slowly
permeates through the walls of the tube at a rate governed by temperature and tube geometry.
Permeation tubes (perm tubes) are a preferred method for delivering precise concentrations from ppb to
high ppm.
pH
A scale used to specify the acidity (0-7 pH) or basicity (7-14 pH) of an aqueous solution.
Probe
A physical device used to connect electronic test equipment to items under test.
Relay
An electrically operated switch consisting of a set of input terminals for a single or multiple control
signals, and a set of operating contact terminals. The switch may have any number of contacts in multiple
contact forms, such as make contacts, break contacts, or combinations thereof.
RS232
Standard for serial communication transmission of data. Once standard for PCs, connections for modems,
printers, data storage, etc.
RS485
Also known as TIA-485 (A), EIA 485; standard defining the electrical characteristics of drivers and
receivers for use in serial communications systems. Supports local networks and multi-drop
communications links.
Soldering
A process in which two or more items are joined together by melting and putting a filler metal (solder)
into the joint, the filler metal having a lower melting point than the adjoining metal.
Spectrometer
A scientific instrument used to separate and measure spectral components of a physical phenomenon.
Spectroscopy
A study of the absorption and emission of light and other radiation by matter, as related to the
dependence of these processes on the wavelength of the radiation.
Stream composition
The makeup of the materials within a specific stream.
TSP
Technical Special Project; an Endress+Hauser term for custom orders.
Vent to atmosphere
The intentional and controlled release of gases containing alkane hydrocarbons - predominately methane
- into earth's atmosphere.
Vent to flare
(flaring)
The controlled burning that takes place during production and processing of gas.
Wavelength
The spatial period of a periodic wave. The distance over which the wave's shape repeats.
Wavelength
modulation
spectroscopy (WMS)
A derivative form of absorption spectroscopy that has been increasingly applied for measurements in
harsh environments due to its improved sensitivity and noise-rejection capabilities over direct absorption.
Used by TDLAS analyzers.

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Operating Instructions SS2100 TDLAS Gas Analyzer
2Safety
Each analyzer shipped from the factory includes safety instructions and documentation to the responsible party or
operator of the equipment for the purpose of installation and maintenance. This manual should be read and
referenced by anyone installing, operating or having direct contact with the analyzer.
Technicians are expected to be trained and follow all safety protocols that have been established by the
customer in accordance with the area hazard classification to service or operate the analyzer.
This may include, but is not limited to, toxic and flammable gas monitoring protocols, lockout/tagout procedures,
the use of personal protective equipment (PPE) requirements, hot work permits and other precautions that
address safety concerns related to the use and operation of process equipment located in hazardous areas.
2.1 Personnel qualifications
Personnel must meet the following conditions for mounting, electrical installation, commissioning and maintenance
of the device. This includes, but is not limited to:
•Be suitably qualified for their role and the tasks they perform:
•Installation, commissioning, operation and maintenance of the measuring system may be carried out only by
specially trained technical personnel.
•Technical personnel must be authorized by the plant operator to carry out the specified activities. Technical
personnel must have read and understood these Operating Instructions and must follow the instructions
contained herein.
•Electrical connections may be performed only by an electrical technician.
•Be trained in explosion protection.
•Be familiar with national and local regulations and guidelines (e.g., CEC, NEC ATEX/IECEx or UKEX).
•Be familiar with lockout/tagout procedures, toxic gas monitoring protocols and PPE (personal protection
equipment) requirements.
•Faults at the measuring point may only be rectified by authorized and specially trained personnel.
Substitution of components is not permitted.
Substitution of components may impair intrinsic safety.
Repairs not described in the Operating Instructions provided must be carried out only directly at the
manufacturer's site or by the service organization.
2.2 Potential risks affecting personnel
This section addresses the appropriate actions to undertake when faced with hazardous situations during or before
service of the analyzer. It is not possible to list all potential hazards within this document. The user is responsible for
identifying and mitigating any potential hazards present when servicing the analyzer.
2.2.1 Exposure to process gas
1. Shut off the process gas to the analyzer before any service that would require opening a part of the sample
plumbing.
2. Purge the system with nitrogen.
3. Shut off the nitrogen purge before opening any part of the sample system.
2.2.2 Exposure to toxic gas (H2S)
Use the following procedure if the SS2100 analyzer included a safety purge kit as ordered. If there has been any
suspected leak from the sample system and accumulated SCS enclosure, do the following:
1. Purge the SCS enclosure to remove any potentially toxic gas.
2. Test the H2S levels of the SCS enclosure using the port from the safety purge kit to ensure the purge has cleared
any toxic gas.
3. If no gas leak is detected, open the SCS enclosure door.

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SS2100 TDLAS Gas Analyzer Operating Instructions
If the SS2100 analyzer was not purchased with a safety purge, purging enclosure as explained in the above procedure
is not possible. Instead, purchase a portable or fixed H2S detector and test at the breather drain or open the enclosure
with the detector at hand to determine if there is a leak.
Follow all safety protocols governing toxic gases and potential leaks.
2.2.3 Electrocution hazard
1. Shut off power at the main disconnect external to the analyzer.
Complete this action before performing any service that requires working near the main input power or
disconnecting any wiring or other electrical components.
If service must be performed with power engaged (gain adjustment, etc.), note any live electrical components
and avoid all contact with them.
2. Only use tools with a safety rating for protection against accidental contact with voltage up to 1000V (IEC 900,
ASTF-F1505-04, VDE 0682/201).
2.2.4 Laser safety
The SS2100 TDLAS Gas Analyzer is a Class 1 laser product, which poses no threat to equipment operators. The laser
internal to the analyzer controller is classified Class 3B and could cause eye damage if the beam is viewed directly.
Before servicing, shut off all power to the analyzer.
2.2.5 Explosion hazard
Any work in a hazardous area must be carefully controlled to avoid creating any possible ignition sources (e.g., heat,
arcing, sparking, etc.). All tools must be appropriate for the area and hazards present. Electrical connections must
not be made or broken with power on (to avoid arcing).
2.3 Product safety
The SS2100 TDLAS Gas Analyzer is designed in accordance with good engineering practice to meet state-of-the-art
safety requirements, has been tested, and left the factory in a condition in which it is safe to operate.
It meets general safety standards and legal requirements. It also complies with the EU directives listed in the specific
EU Declaration of Conformity. Endress+Hauser confirms this by affixing the CE mark to the analyzer system.
2.3.1 General
•Adhere to all warning labels to prevent damage to the unit.
•Do not operate the device outside the specified electrical, thermal and mechanical parameters.
•Only use the device in media to which the wetted materials have sufficient durability.
•Modifications to the device can affect the explosion protection and must be carried out by staff authorized to
perform such work by Endress+Hauser.
•Install the controller circuit wiring according to the Canadian Electrical Code (CEC) respective National Electrical
Code (NEC) using threaded conduit or other wiring methods in accordance with NEC articles 501 to 505, or IEC
60079-14.
•Install the device according to the manufacturer’s instructions and regulations.
•The flameproof joints of this equipment are outside the minimums specified in IEC/EN 60079-1 and shall not be
repaired by the user.
Only open the controller cover if the following conditions are met:
•An explosive atmosphere is not present
•All device technical data is observed (see nameplate)

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Operating Instructions SS2100 TDLAS Gas Analyzer
•An electrostatic charge (e.g., caused by friction, cleaning or maintenance) is avoided on the attached stainless
steel nameplate, if present, and on painted metallic housings that are not integrated into the local potential
equalization (ground) system
In potentially explosive atmospheres:
•Do not disconnect any electrical connections while the equipment is energized.
•Do not open the connection compartment cover when energized or the area is known to be hazardous.
2.3.2 General pressure
The system is designed and tested with appropriate margins to ensure that is it safe under normal operating
conditions, which include temperature, pressure, and gas content. The operator is responsible for ensuring that the
system is shut off when these conditions are no longer valid.
2.3.3 Electrostatic discharge
The coating and the adhesive label is non-conducting and may generate an ignition capable level of electrostatic
discharge under certain extreme conditions. The user should ensure that the equipment is not installed in a location
where it may be subjected to external conditions, such as high pressure steam, which may cause a build-up of
electrostatic charges on non-conducting surfaces. To clean the equipment, use only a damp cloth.
2.3.4 Chemical compatibility
Never use vinyl acetate or acetone or other organic solvents to clean the analyzer housing or labels.
2.3.5 Canadian Registration Number
In addition to the requirements above for general pressure safety, Canadian Registration Number (CRN) systems
must be maintained using CRN approved components without any modification to the sample conditioning system
(SCS) or analyzer.
2.4 Workplace safety
As the user, you are responsible for complying with the following safety conditions:
•Installation guidelines
•Local standards and regulations
•Regulations for explosion protection
It is not possible to list all potential hazards within this document. The user is responsible for identifying and
mitigating any potential hazards present when servicing the analyzer.
Technicians are expected to follow all safety protocols established by the customer that are necessary for servicing
the analyzer. This may include, but is not limited to, lockout/tagout procedures, toxic gas monitoring protocols,
personal protective equipment (PPE) requirements, hot work permits and other precautions that address safety
concerns related to performing service on process equipment located in hazardous areas.
2.5 Operational safety
Before commissioning the entire measuring point:
1. Verify that all connections are correct.
2. Ensure that electrical cables and hose connections are undamaged.
3. Do not operate damaged products, and protect them against unintentional operation.
4. Label damaged products as defective.
During operation:
1. If faults cannot be rectified, products must be taken out of service and protected against unintentional operation.
2. Keep the door closed when not carrying out service and maintenance work.

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SS2100 TDLAS Gas Analyzer Operating Instructions
2.6 Lifting provisions for the analyzer
Due to the analyzer’s size and weight (configurations can weigh approximately 90 to 154 kg [200 to 340 lbs] with
sample conditioning system), the use of a forklift, pallet jack, etc. to lift or move the analyzer is recommended. If the
analyzer is to be lifted by hand, designate multiple individuals and distribute the weight among personnel to avoid
injury.
Before removing from the crate, move the analyzer as close as possible to the final installation location. Never lift the
analyzer by the electronics enclosure. Always carry the load using one of the following points/methods (refer to
Mounting the analyzer → ):
•Mounting points
•Support beneath instrument (best used when employing a forklift)
Always use a lifting truck or a forklift to transport the analyzer. Two people are needed for the installation.
Ensure all equipment used for lifting/moving the analyzer is rated for the weight load.
Lift the device by the recessed grips.

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Operating Instructions SS2100 TDLAS Gas Analyzer
3Product description
The SS2100 TDLAS Gas Analyzers are tunable diode laser (TDL) absorption spectrometers operating in the near- to
short-wavelength infrared. Each compact sensor consists of a TDL light source, sample cell and detector specifically
configured to enable high sensitivity measurement of a particular component within the presences of other gas
constituents in the stream. The sensor is controlled by microprocessor-based electronics with embedded software
that incorporates advanced operational and data processing algorithms.
The SS2100 TDLAS Gas Analyzer is typically comprised of two main enclosures; the analyzer electronics and the
sample conditioning system (SCS). On the front panel of the analyzer electronics, the keypad and LCD display serve
as the user interface to the analyzer. Some systems may also have a keypad cover. The analyzer control electronics
drive the laser, collect the signal, analyze the spectra and provide measurement output signals.
The figure below shows two sample SS2100 analyzer configurations from front view.
Fig 1. SS2100 TDLAS Gas Analyzer for single analyte (left) and multiple analytes (right), front view
1. Solenoid valve junction box for trace applications (when applicable) 4. Analyzer A for H2S (2-pack and 3-pack multiple analyte systems)
2. Analyzer electronics for single analyte systems 5. Analyzer B for H2O and CO2(2-pack and 3-pack multiple
3. Sample conditioning system enclosure analyte systems)
5
2
1
4
3

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SS2100 TDLAS Gas Analyzer Operating Instructions
3.1 How Endress+Hauser TDLAS Gas Analyzers work
The Endress+Hauser SS2100 analyzers employ SpectraSensors tunable diode laser absorption spectroscopy (TDLAS)
to detect the presence of substances in process gases. Absorption spectroscopy is a widely used technique for
sensitive component detection. Because the measurement is made in the gas stream, the response is faster, more
accurate, and more reliable than traditional surface-based sensors that are subject to contamination.
In its simplest form, a diode laser absorption spectrometer typically consists of a sample cell with a window or mirror
at one end, through which the laser beam can pass, and a mirror at the opposite end. The figure below shows 0.8 m
cell and 8 m/28 m cell cross-sections with indicators for standard components and access. The laser beam enters the
cell and reflects off the mirror(s) making multiple passes through the sample gas and eventually exiting the cell
where the remaining beam intensity is measured by a detector. With the SS2100 analyzers, sample gas flows
continuously through the measurement cell ensuring that the sample is always representative of the flow in the
process main pipe.
0.1 m cell
0.8 m cell
8 or 28 m cell
Fig 2. Schematic of a typical laser diode absorption spectrometer
1. Laser 5. Detector
2. Pressure sensor 6. Window/near mirror
3. Outlet 7. Inlet
4. Optical head 8. Far mirror
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 trace 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 / (cell length x number of passes), is given by
󰇛󰇜 󰇛󰇜󰇟󰇛󰇜󰇠
4
15
6
7
2
83
4
1 5
6
7
2
3 8
4
1 5
6
7
8 3
2

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Endress+Hauser
Operating Instructions SS2100 TDLAS Gas Analyzer
where N represents the species concentration. 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
N= 
󰇛󰇜󰇣󰇛󰇜 󰇛󰇜󰇤
Below, figure 3 shows the typical raw data from a laser 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 intensity to mirror contamination). The positive slope 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 the figure below.
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. As a result, self-calibration
allows for measurements that are unaffected by mirror contamination.
Fig 3. Typical raw signal from a laser diode absorption spectrometer with and without mirror contamination
A. Resonance absorption Blue line: raw signal, I (l)
B. Red line: incident energy I0(l) Green line: raw signal, I (l) (contaminated mirrors)
Fig 4. Typical normalized signal from a laser diode absorption spectrometer
Wavelength [a.u.]
Wavelength [a.u.]
1.0
0.99
0.98
0.97
0.96
0.95
Wavelength [a.u.]
Signal [a.u.]
3.0
2.5
2.0
1.5
1.0
0.5
0.0
A

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SS2100 TDLAS Gas Analyzer Operating Instructions
3.1.1 Non-differential TDLAS
In all SS2100 TDLAS Gas Analyzers, non-differential TDLAS is designed for higher concentration analytes, including
H2S, H2O, NH3, CO2, C2H2, and others. In non-differential systems, spectroscopy measurements are made directly
from the sample without subtracting the wet spectrum from the dry spectrum as described below for differential
systems. Endress+Hauser non-differential models do not include a dryer or scrubber for measurement validation.
3.1.2 Differential TDLAS
Differential TDLAS is featured in the SS2100 TDLAS Gas Analyzers for trace measurements, including low
concentrations of hydrogen sulfide (H2S), moisture (H2O), and ammonia (NH3). This technology involves subtracting
one spectrum from another. A dry spectrum, the response from a sample when the analyte of interest has been
completely removed, is subtracted from the wet spectrum, the response from the sample when the analyte is present.
The remainder is a spectrum of the pure analyte. This technology is used for very low or trace measurements and is
also useful when the background matrix changes over time.
3.1.3 Wavelength modulation spectroscopy (WMS) signal detection
Endress+Hauser takes absorption spectroscopy a step further by using a sophisticated signal detection technique
called wavelength modulation spectroscopy (WMS). With WMS, the laser drive current is modulated with a kHz sine
wave as the laser is rapidly tuned. An amplifier is then used to boost the harmonic component of the signal that is
twice the modulation frequency (2f), as shown in the figure below. This phase-sensitive detection enables the
filtering of low-frequency noise caused by turbulence, temperature, or pressure fluctuations in the sample gas,
low-frequency noise in the laser beam or thermal noise in the detector.
Fig 5. Typical normalized 2f signal showing species concentration proportional to height
A. 2f peak height
B. Normalized 2f signal
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).
Measuring different trace gases in various mixed hydrocarbon background streams is accomplished by selecting a
different optimum diode laser wavelength between 700 to 3000 nm, which provides the least amount of sensitivity
to background stream variations.
Wavelength [a.u.]
Signal [a.u.]
B
A

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Endress+Hauser
Operating Instructions SS2100 TDLAS Gas Analyzer
3.2 SS2100 TDLAS Gas Analyzer model types
The SS2100 TDLAS Gas Analyzers are separated into differential or non-differential systems. In some cases, the
SS2100 includes a permeation validation system for generating a known analyte concentration.
SS2100 TDLAS Gas Analyzers are comprised of two main enclosures; the analyzer electronics and the sample
conditioning system (SCS). On the front panel of the analyzer electronics, the keypad and LCD display serve as the
user interface to the analyzer. Some systems also have a keypad cover. The analyzer control electronics drive the
laser, collect and analyze the spectra, and provide measurement outputs. Inside the analyzer electronics enclosure is
the electronics assembly. Fuses are located on the electronics control board.
Housed inside the SCS are the measurement cell, heater, and sample system components to control flow and pressure
for the measurement cell and the bypass loop. Power is connected to the analyzer from a 120 VAC, 240 VAC, or
24 VDC power source. The sample supply, sample return, and instrument air are connected on the opposite side of
the enclosure.
3.2.1 The non-differential SS2100 TDLAS Gas Analyzer
The non-differential Endress+Hauser SS2100 TDLAS Gas Analyzers measure higher concentrations of analytes,
including H2O, CO2, H2S, NH3, and C2H2.
Fig 6. SS2100 non-differential analyzer, front view
1Signal wiring
2Analyzer electronics enclosure
3Analyzer power
4Sample supply
5Sample return
6Signal wiring
7LCD display and keypad
8Temperature indicator
9Sample conditioning system
10 Heater power
11 Chassis ground
1
2
3
4
5
6
7
8
9
10
11

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SS2100 TDLAS Gas Analyzer Operating Instructions
3.2.2 The differential SS2100 analyzers for trace measurements
The SS2100 TDLAS Gas Analyzer for trace measurements features specialized equpiment for mitigating and
measuring these analytes. Permeation validation is a method for validating low H2O and NH3measurements. For
information on using permeation validation, see Permeation validation → . For information on servicing the
scrubber for trace measurements, see Replacing the scrubber → .
Differential system for hydrogen sulfide (H2S)
The Endress+Hauser SS2100 TDLAS Gas Analyzer for trace hydrogen sulfide (H2S) features a differential TDLAS
system. Below a sample SS2100 analyzer for H2S is shown from the front view.
Fig 7. SS2100 analyzer for hydrogen sulfide (H2S), front view
1Solenoid valves (air-operated valves
optional)
2Analyte scrubber
3Filter
ASample supply, ~207 kPa (~30 psig)
BSample return, to safe area
4Sample/reference gas on/off
5Membrane separator
6Pressure relief valve
7Bypass flow indicator and control
8Bypass pressure gauge
9Heater
10 Vent gas on/off
11 Cell inlet port
12 Analyzer flow indicator and control
13 Analyzer pressure gauge
14 Scrubber indicator
15 Pressure regulator
16 Cell outlet port
17 Temperature controller
11
12
13
14
15
16
17
1
2
3
4
A
5
6
7
8
B
9
10

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Endress+Hauser
Operating Instructions SS2100 TDLAS Gas Analyzer
The SS2100 TDLAS Gas Analyzer for H2S features specialized equpiment for mitigating and measuring this particular
analyte. For information on servicing the H2S scrubber indicator, see Servicing the H2S scrubber → .
Differential system for trace moisture (H2O) and ammonia (NH3)
The Endress+Hauser SS2100 TDLAS Gas Analyzers for trace moisture (H2O) and ammonia (NH3) feature a
differential TDLAS system. These systems also require external solenoid housing to prevent temperature fluctuations
within the sample conditioning system.
Endress+Hauser SS2100 TDLAS Gas Analyzers for trace moisture (H2O) and ammonia (NH3) include a permeation
tube and scrubber for measurement validation. If your SS2100 analyzer is configured for trace ammonia (NH3), the
permeation tube has been shipped separately and must be installed prior to commissioning the analyzer. See
Installing the permeation tube for NH3systems → .
Below a sample SS2100 analyzer for H2O is shown from the front view.
Fig 8. SS2100 analyzer for trace measurements, including H2O and NH3
1Solenoid valve junction box
26-way valve
3Air-operated 3-way valve
4Filter
5Diaphragm valve
ASample supply, ~207 kPa (~30 psig)
BSample return, to safe area
6Heat trace boot
7Pressure relief valve
8Pressure gauge
9Bypass flow indicator and control
10 Analyzer flow indicator and control
11 Vent gas on/off
12 Heater
13 Cell inlet port
14 Filter
15 Permeation tube
16 Scrubber
17 Cell outlet port
18 Pressure regulator
19 Metering valve
20 Temperature controller
1
2
3
4
5
6
A
7
8
9
10
B
11
12
18
14
16
13
15
17
19
20

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SS2100 TDLAS Gas Analyzer Operating Instructions
3.2.3 SS2100 TDLAS Gas Analyzers for multiple analytes
2-pack and 3-pack system
The Endress+Hauser SS2100 2-pack and 3-pack TDLAS Gas Analyzers for multiple analytes feature a differential
TDLAS system. 2-pack and 3-pack analyzer systems are designed for use with extractive natural gas sampling
stations.
SS2100 2-pack systems generally contain one analyzer for H2S measurements (analyzer A) and one analyzer
dedicated to measurements for H2O or another analyte (analyzer B). SS2100 3-pack systems also contain two
electronic enclosures. In the 3-pack system, analyzer A is dedicated to H2S measurements while analyzer B typically
reads H2O and CO2measurements.
Fig 9. SS2100 2-pack and 3-pack analyzer external structure, front view
1Signal wiring
2Analyzer A electronics enclosure
3Analyzer power
4Instrument air inlet (optional)
5Validation gas inlet (optional)
6High H2S purge (optional)
7Sample supply
8Sample return
9Enclosure purge vent (optional)
10 LCD display and keypad
11 Signal wiring
12 Analyzer B electronics enclosure
13 Analyzer power
14 Temperature indicator
15 Sample conditioning system
16 Heater power
17 Enclosure ground
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17

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Operating Instructions SS2100 TDLAS Gas Analyzer
2-pack and 3-pack systems with OXY5500
The Endress+Hauser SS2100 2-pack and 3-pack with OXY5500 TDLAS Gas Analyzers for multiple analytes feature a
differential TDLAS system. Most 3-pack analyzer systems are configured for use at extractive natural gas sampling
stations.
Fig 10. SS2100 2-pack and 3-pack with OXY5500 analyzer external structure, front view
1H2O/CO2analyzer signal wiring
2H2S analyzer signal wiring
3H2S (analyzer A) electronics enclosure
4H2S analyzer power
5Temperature indicator
6Sample conditioning system
7Sample supply
8Sample return
9H2O/CO2(analyzer B) electronics enclosure
10 LCD display and keypad
11 O2(analyzer C—OXY5500) electronics
enclosure
12 O2 pressure sensor
13 O2 probe
14 RTD probe
15 O2calibration inlet
16 Heater power
17 Enclosure ground
9
10
11
12
13
14
15
16
17
1
2
3
4
5
6
7
8