SITRANS SL Laser Diode Gas Analyzer

Laser Diode Gas Analyzer

SITRANS SL is designed for measuring oxygen (O2) with high sensitivity. It consists of a pair of cross-duct sensors, a transmitter unit and a detector unit, both with the same dimensions. Due to its little installation effort and its minimum maintenance requirements, SITRANS SL guarantees a high level of economic efficiency.

SITRANS SL Gas Analyzer (TDLS) - Quick and reliable gas analysis under extreme conditions

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Laser diode gas analyzer

SITRANS SL – easy to handle with contact-free measurement

The in-situ SITRANS SL gas analyzer features high operational availability, unique analytical selectivity, and a wide range of possible applications. SITRANS SL permits measurement of a gas component directly in the process

The SITRANS SL gas analyzer consists of a pair of cross-duct sensors, a transmitter unit and a detector unit, both with the same dimensions.  The sensors (transmitter and receiver) are meant to be mounted directly on the process with no need of sampling systems. The hardware for processing the measurement signal into a concentration value as well as monitoring, control and serving of the communication means are also integrated into these two main modules. The sensors are designed for operation under harsh environmental conditions. Laser light is sent from the transmitter, passing through the process gas, arriving at the detector on the receiver side. The measurements are carried out on-line with a very short response time permitting fast and effective cost-savings in process control. The laser characteristics allow single-line spectroscopy free of interferences. Since the band width of the laser light is extremely narrow, only the gas component of interest will interact with it. Other process influences, such as dust and temperature, are easily eliminated due to the excellent inherent compensation capabilities of this technique. 

High functionality with remote control

The detector unit is connected to the transmitter unit by means of a sensor cable. A further cable on the receiver is used to connect the power supply and the communication interfaces. The receiver enclosure contains a local user interface (LUI) with an LC display which can be read through a window in the cover. The LUI is operated by remote control.


Innovative solution for calibration

An in-line reference cell filled with a non-interfering reference gas, a further development of the already established Siemens TDL technology, provides unique user benefit in terms of minimum need for maintenance and recalibration. 


  • Process control (chemical industry) 
  • Process optimization (steel industry)
  • Safety monitoring, e.g. measuring minimum or maximum concentration limit for oxygen in explosive proof environment
  • Combustion control (boilers, municipal waste incinerators) 

Technical data

Max. number of components 
Smallest measuring range 
O2: 0-1 Vol%
field version

Benefits at a glance

  • Little installation effort 
  • Minimum maintenance requirements 
  • Extremely rugged design 
  • High long-term stability through built-in, maintenance-free reference gas cell 
  • Real-time measurements 
SITRANS SL Gas Analyzer (TDLS)

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Information at a glance

Whether you would like to know more about our In-situ analytical devices, have technical questions, or need spare parts, we have summarized essential additional information for you below.
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To remain competitive, companies in industry must ensure – and ideally increase – the availability and productivity of machines and plants. As your partner, we offer a unique range of services and support based on our extensive technology and industry expertise.

USA | Siemens Industry Online Support (SIOS)

Siemens Industry Online Support (SIOS)

As your partner, we offer a unique range of services and support based on our extensive technology and industry expertise. With our offerings, you can expect a high degree of reliability and a successful digital future for your company.


Well trained for excellent handling

Siemens experts are available with a variety of training courses and to help you understand gas chromatography and continuous gas analysis and how to operate and maintain your Siemens analytical products. Siemens offers both introductory and advanced courses several times a year.


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