MultiGas Sensors



  • Analyze up to 4 different gases
  • Detection Limit is the smallest measurement
  • Short specification 3

MultiGas Sensor

Modular sensor design

Analyse up to 4 different gases plus pressure and humidity simultaneously in order to adapt gas analysis as flexibly as possible to individual measurement tasks, the single components were designed modularly. This resulted in a »modular system« in which the various photometric components such as detectors, emitters, measuring sample cell, etc. can be assembled user-specifically.

With this sophisticated sensor design, customer-specific applications can be realized without needing a completely new development. The modularity makes replacement and maintenance considerably easier when servicing is required. In contrast to this design, common completely glued gas sensors can only be replaced as a complete unit thus generating high follow-up costs (total cost of ownership) in case of maintenance. Optionally, modules can also be equipped with a sensor for oxygen, pressure, and humidity.

Configurations and Measurement Ranges

Infrared module NDIR Ultraviolet module NDUV Ultraviolet module NDUV / UVRAS* Calibration with Propane

Modules built into table-top casing.

Non-Dispersive Infrared Sensor (NDIR) MultiGas Sensor

  • CO2 CO N2O CNHM CH4 C2 H6 C3H8 C4H10 CF4 H2O
  • NDIR Sensor = non-dispersive infrared sensor
  • Featuring high-performance light-emitting diodes (IR-LED) and thermal micro-radiators


The RITTER MultiGas Sensors NDIR Module (non-dispersive IR sensor) has been specially developed for use in high-quality gas analysis. In the design phase special emphasis was placed on high stability and a low detection limit. These goals could be fully achieved by using high-performance light-emitting diodes (IR-LED) and thermal micro-radiators which were adapted to the requirements of gas detection. In the spectral range from 2 μm to 12 μm, carbon dioxide, carbon monoxide, hydrocarbons, water vapor and sulphur hexafluoride can be safely detected down to the ppm range with this innovative sensor platform.

The various photometric components such as detectors, emitters, measuring sample cell, etc. will be assembled user-specifically in a high-quality tabletop casing by RITTER.

 MultiGas Infrared Module NDIR Datasheet


Non-Dispersive Ultraviolet Sensor (NDUV) MultiGas Sensor



The RITTER MultiGas UV sensor is the world’s first gas analysis module based on miniaturized UV-LEDs. The stability and lifetime of these UV-LEDs enables high-precision gas analysis down to the ppm range. By using two UV-LEDs two gases can be detected simultaneously. Furthermore, with this approach measuring ranges from ppm to Vol.-% can be realized. In the spectral range from 200 nm to 500 nm, nitrogen oxides (NO + NO2), aromatic hydrocarbons, hydrogen sulphide, ozone, sulphur dioxide and chlorine can be reliably detected with this new sensor platform.

MultiGas Ultraviolet Module NDUV Datasheet


 Non-Dispersive Ultraviolet Sensor NDUV/UVRAS MultiGas

  • SO2 NOX NO2 NO
  • UVRAS = UV resonance spectroscopy
  • Allows simultaneous gas analysis of NO, NO2 and SO2


 For the detection of NO an EDL (electrodeless gas discharge lamp) is used. In the EDL, N2 and O2 are converted to NO and produce a selective UV radiation. With this radiation, a cross-sensitivity-free NO measurement is made possible. This method is called UV resonance absorption spectroscopy (UVRAS). A combination of both the UVRAS and NDUV technology allows the simultaneous gas analysis of NO, NO2 and SO2 in the lower ppm range which is particularly important in flue gas analysis (Continuous Emission Monitoring, CEM).

 MultiGas Ultraviolet Module NDUV / UVRAS



MultiGas Ultraviolet Module NDUV H2S

  • H2S

The H2S sensor works according to the principle of non-dispersive UV absorption (NDUV). The measuring wavelength used is in the lower nanometer range, which enables interference-free measurements with water vapour and hydrocarbons. This makes the sensor ideal for use in biogas measurements, as accompanying gases such as NH3, CO2, CH4 and H2O do not affect the accuracy of the measurements.

MultiGas Ultraviolet Module NDUV H2S DATA SHEET



MultiGas Infrared plus Ultraviolet Module

  • CO2 CO N2O CNHM CH4 C2H6 C3H8 C4H10 CF4 SF6 H2O O3 CL2 CLO2 CS2 SO2 H2S NOX NO2 NO
  • Combination of NDIR and NDUV Sensor
  • Enables the measurement of 3 gas components simultaneously.

RITTER MultiGas Modules can also be a combination of both NDIR sensors and NDUV sensors on a common board. With this unit, up to 3 gas components can be measured simultaneously. The basic electronics can supply IR and UV radiation sources with different frequencies for 0 Hz (DC) to 100 Hz (AC). This system is an ideal tool for detecting multi-component gas at low ppm levels.

Please note: For technical and chemical reasons, not every combination of gases/measuring ranges can be analysed/measured in a single or combined RITTER   MultiGas module. As this is a rather complex topic, please do not hesitate to contact one of our gas experts first.

MultiGas Infrared plus Ultraviolet Module DATA SHEET

Contact Us for further details.

Additional sensors / Sensor options

Oxygen Sensor

  • Electrochemical sensor
  • Measuring ranges:
    • Standard version 0 – 25 % or 0 – 100 %
    • H2S resistant version 0.5 – 35 %
  • Measurement accuracy ±2 % of span (full scale)
  • Resolution: < 0.5 % of span (full scale)
  • Response time (t90): 5 – 10 s; automotive version < 3.5 s
  • Lifetime: approx. 5 years

Read More Oxygen Sensor

Pressure Sensor

  • Pressure compensation of measured gas concentrations
  • Measuring ranges:
    • Standard version 800 – 1,200 mbar abs.
    • H2S resistant version 0.2 – 3.5 bar abs.
  • Measurement accuracy ±1% of span (full scale)
  • Resolution: <1 mbar (2 mbar for H2S resistant version)
  • Response time (t90): 1 s
  • Incl. temperature compensation

Read More Pressure Sensor

Humidity sensor

  • Polymer humidity sensor
  • Measuring range: 0-100% rH
  • Measurement accuracy ±2% rH of span (full scale)
  • Resolution: ±1% rH
  • Response time (t90): 12 s
  • Incl. temperature compensation
  • Indicated values: absolute [% absH] and relative humidity [% rH]

Read More Humidity sensor

Analog Voltage Output

  • Allows the output of gas concentration values for up to 4 different gases at 4 separate channels
  • 4 parallel signal outputs
  • 3 x gas concentration signals including oxygen sensor
  • 1 x value from humidity sensor
  • Resolution: 16 bit
  • Update rate: 1 sec

Read More Analog Voltage Output

Case Heating

  • Prevents condensation of humid gas inside of the sensor
  • Temperature controller: 30 – 50 °C
  • Control accuracy: ± 0.2 K
  • Heating power: 12 Watt

Read More Case Heating


Humidity Sensor

The HUMI.sens® is based on a capacitive humidity sensor. This sensor consists of a hygroscopic polymer material in which the water vapor from the measurement gas is stored. This incorporation …


Within the infrared spectral range between 2 µm to 12 µm or 14 µm the IR photometry can detect different gases. This spectral range is much larger than the UV …

Oxygen Sensor

The O2.sens from Wi.Tec is based on an electrochemical process. In this process, a chemical reaction takes place with the oxygen to be measured and a liquid electrolyte. In this …


The UV photometry is based on the absorption of radiation in the spectral range between 200nm and 400nm. In this area, some important technical gases have a pronounced absorption band. …



Manufacturer: Ritter

Media Type: Gases


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