SERVOTOUGH Laser 3 Plus Process

The compact Laser 3 Plus Process enables fast, accurate process control measurements

The Laser 3 Plus Process Tunable Diode Laser (TDL) analyzer provides all the benefits of Servomex’s TDL Absorption Spectroscopy technology in a small, light unit, offering unparalleled installation flexibility plus cost and performance benefits. It is optimized for the fast, accurate and responsive measurement of process oxygen (O2) in hot or hazardous conditions.

  • A revolutionary approach to TDL gas analysis
  • Low maintenance, low cost-of-ownership
  • High performance monitoring

Ready to buy? Here’s how it works

It’s easy to find the product you need for your application with Servomex


Get in touch to tell us what you need and the application you plan to use it for


Our expert team will help you select the right product package, ensuring you have the accessories and support to get the best performance from your analyzer


Your analyzer will be assembled in one of our state-of-the-art engineering centers and rapidly dispatched to your site

Process gas analysis with unique features and low cost-of-ownership

Rhys Jenkins
Rhys Jenkins
IP&E Spectroscopic Product Manager

The SERVOTOUGH Laser 3 Plus Process is a highly compact gas monitor for in-situ cross stack applications, delivering exceptional performance benefits in a revolutionary compact design. Its pioneering design occupies a footprint up to one-tenth the size of competitor products, providing instant benefits for installation and flexibility.

Utilizing the latest Wavelength Modulated Spectroscopy (WMS) measurement techniques with unique Servomex signal processing, it provides the most stable, repeatable results for the measurement of O2, with minimal installation and maintenance costs.

A revolutionary approach to TDL gas analysis

By combining the latest advances in hardware with leading-edge software processing, the SERVOTOUGH Laser 3 Plus is a revolutionary step forward for TDL gas analysis. Servomex has approached TDL analysis afresh, creating an analyzer a fraction of the size without compromising performance. The result is TDL analysis that is easier and faster to install – saving valuable space while enabling much greater installation flexibility.

Low maintenance, low cost-of-ownership

The next-generation ethos of the Laser 3 Plus works hard to reduce costs at all stages. In addition to the immediate advantages of TDL technology – a non-depleting measurement which requires no sample conditioning system – the Laser 3 Plus compact design greatly reduces installation time, with small, light intuitive alignment for easy installation and maintenance. Full ethernet communications for commissioning, diagnostics and trouble shooting.

High performance monitoring

The hardware advances of the Laser 3 Plus are matched by advanced Wave Length Signal Modulated Spectroscopy processing software which eliminates drift over extended operational periods by automatically tracking on a sealed reference cuvette absorption line – Line Lock Technology. This robust tracking mechanism ensures a highly reliable and accurate operation over long periods, with calibration frequencies extended beyond twelve months for many applications. The result is a sturdy, general purpose and hazardous area optimized design which ensures Laser 3 Plus can handle the most challenging of locations; including particulate-rich environments.

Man with Servomex System components

Building a system? We’re the experts

If you’re looking to build a complete gas analysis solution, we can help. Get in touch from the start for advice, expert project management, and high-quality engineering. Our collaborative approach ensures you get the efficient, cost-effective system you need.

Optimized for process oxygen measurements

The Laser 3 Plus Process is a compact TDL analyzer with a wide range of features and benefits, and a fast, accurate response to changing O2 levels.

A compact design

The Laser 3 Plus Process is small enough to be easily installed by a single engineer, while the on-board display negates the need for laptop configuration.

Reliable measurements

Using Servomex’s own line lock cuvette technology, the Laser 3 Plus Process continues to measure oxygen reliably, for high safety integrity.

Approved for hazardous conditions

The Laser 3 Plus Process has ATEX, IECEx and North American hazardous area approvals, is approved for process Zone 2, SIL 2 assessed, and CE marked.

Unrivalled performance

  • Process temperatures up to 500°C
  • Low detection limit
  • Negligable zero drift
  • Calibration 6-12 month
  • Fast response


  • Compact design
  • Performs in high particulate environments
  • Minimal cross interference
  • Diverse mounting: ideal for ducts, stacks and reactor installations

Easy to use

  • Simple to install and operate
  • Robust and reliable
  • Space saving
  • Digital communications
  • Modbus over Ethernet
  • User friendly interface and rapid disconnect for easy calibration

Low cost of ownership

  • Intuitive alignment for easy installation and maintenance
  • Non-depleting TDL technology
  • No moving parts, no consumables
  • No sample conditioning system – reduced maintenance costs
  • No hazardous area purge required

Benchmark compliance

  • ATEX, IECEx hazardous area approvals
  • North American hazardous area Class 1 Div 2
  • IP66
  • SIL 2
  • CE approved

The SERVOTOUGH Laser 3 Plus Process is optimized for the measurement of process oxygen in applications under hot or hazardous conditions.

Gas Measurement
Oxygen (O₂)%


Tunable Diode Laser
Laser 3 Plus Process Tunable Diode Laser (TDL) analyzer


  • ATEX Cat 3 (Gases)
  • IECEx Zone 2 and Zone 21
  • North American Class 1 Division 2 and Zone 2 (Gas and Dust) pending
  • ATEX Cat 21 (Dust)
  • Safe Area / General Purpose
  • CE marked in compliance with ATEX, EMC, LVD and all other applicable directives

Schematics (select to expand)


131mm width (51/8”) 164mm high (61/2”) 302.4mm deep (119/10”) 

110mm width (45/16”) 146mm high (53/4”) 247.6mm deep (93/4”) 


TRANSMITTER: <3.0 kg (6.6 lbs)

RECEIVER: <2.0 kg (4.4 lbs)

Get the detailed specifications

“For in-depth specifications you’ll want to download our technical datasheet which includes information on technology, performance, operating environment, sample conditions and compliance along with technical drawings and top-level benefits and applications.”

Rhys Jenkins
Rhys Jenkins
IP&E Spectroscopic Product Manager

Get all the Laser 3 Plus Process resources you need

“Our resource pack for the Laser 3 Plus Process analyzer contains a comprehensive set of information including the product brochure and manual. Download it now for features, benefits and technical specifications about this innovative TDL monitor.”

Rhys Jenkins
Rhys Jenkins
IP&E Spectroscopic Product Manager

Manuals and brochures

Find out more about the advantages offered by the Laser 3 Plus Process – download the product brochure and operator manual

SERVOTOUGH Laser 3 Plus Certification Manual | Product certification

SERVOTOUGH Laser 3 Plus Certification Manual | Product certification

SERVOTOUGH Laser 3 Plus Product Brochure

SERVOTOUGH Laser 3 Plus Product Brochure

SERVOTOUGH Laser 3 Plus Process Product Brochure

SERVOTOUGH Laser 3 Plus Process Product Brochure

SERVOTOUGH Laser 3 Plus Product Configuration

SERVOTOUGH Laser 3 Plus Product Configuration

See for yourself

Our videos give you the chance to watch our products in action and hear from our experts. You can also see our analyzers unboxed, and find out more about our solutions for key applications

Lasers for Safety and Process Control

Learn about the role of the SERVOTOUGH Laser 3 Plus in fired heater combustion

Ammonia Slip Applications

See how the SERVOTOUGH Laser 3 Plus provides an analytical solution for this application

Laser 3 Plus Installation

Our expert demonstrates how easy it is to install the Laser 3 Plus


See the compact, fast-response performance of this innovative analyzer 

Unboxed: SERVOTOUGH Laser 3

Watch our expert Product Specialist Luke Purdie unpack this innovative TDL gas analyzer and explain its features and benefits in a range of applications.

Typical applications

Process heaters and furnaces

A choice of technologies to fit your application

Learn more

Coal-fired thermal power

Our total analytical solution delivers benefits in cost, process efficiency & safety.

Learn more

Still need to know more? Talk to one of our experts

If you haven’t yet been convinced, then speak to our experts. They’ll give you the best, most knowledgeable explanation of our solutions, and help you find the one that’s most suitable for your application.

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