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Operation Manual – MultiGas Sensors

Table of Contents

General Specifications

Casing Types

RITTER NDIR & NDUV Sensor Casing Type 1
Type 1
RITTER NDIR & NDUV Sensor Casing Type 2
Type 2

Dimensions

Casing Type 1 Casing Type 2
A 171 mm 444 mm
B 290 mm (1) 305 mm
C 86 mm 145 mm
Weight, approx. (2) 2+ kg 6.5 – 8 kg
Connections gas in-/outlet PVDF screw-type tube connection for tube Øi 4 mm, Øo 6 mm
Interfaces USB (standard), RS232 / CANbus / CANopen (options)
Power supply 24 V DC, incl. plug-in power supply unit
100-240 V-AC, 50/60 Hz
(1) May be larger with cuvettes for ppm measurement ranges
(2) Depending on type and number of built-in sensor modules

Assignment of Sensor Types to possible Sensor Combinations

Part 1: Pre‐configured Sensors incl. Casing Type 1

With gas connection fittings, data interface, plug-in power supply – ready for use

Sensor Type: 
RITTER MultiGas xxx		 Article
No.		 Group of Gases
IR		 Number of Detectable Gases
in this Group		 Group of Gases
UV		 Number of Detectable Gases
in this Group
xxx = mono IR1 2678
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
1
xxx = duo IR2 2742
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
2
xxx = trio IR3 2743
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
3
xxx = mono UV1 2749
O3 Cl2 ≤ 5% SO2 NO2
1
xxx = mono UV1 Cl2 30% 2763
Cl2 ≤ 30%
1
xxx = duo UV2 2766
O3 Cl2 ≤ 5% SO2 NO2
2
xxx = duo IR1 +  UV1 2797
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
1
O3 Cl2 ≤ 5% SO2 NO2
1
xxx = trio IR1 +  UV2 na
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
1
O3 Cl2 ≤ 5% SO2 NO2
2
* Calibration with Propane

Part 2: Pre‐configured Sensors incl. Casing Type 2

With gas connection fittings, data interface, plug-in power supply – ready for use

Sensor Type: 
RITTER MultiGas xxx		 Article
No.		 Group of Gases
IR		 Number of Detectable Gases
in this Group		 Group of Gases
UV		 Number of Detectable Gases
in this Group
xxx = mono UV1 H2S ≤ 5.000 ppm 2672
H2S ≤ 5.000ppm
1
xxx = mono UV1 H2S ≤ 1% 2855
H2S ≤ 1%
1
xxx = UVRAS 2812
SO2 NO2 NO
1
xxx = duo IR1 + H2S ≤ 5000 ppm 2959
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
1
H2S
1
xxx = duo IR1 + (H2S ≤ 1% / NO) 2960
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
1
H2S ≤ 1% NO
1
* Calibration with Propane

Part 3: Individually combinable Sensor Modules

Composition according to customer specification, delivery incl. housing in suitable size according to number and type of modules – ready for use

Sensor Type: 
RITTER MultiGas xxx		 Article
No.		 Group of Gases
IR		 Number of Detectable Gases
in this Group		 Group of Gases
UV		 Number of Detectable Gases
in this Group
xxx = Mod IR1 2813
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
1
xxx = Mod IR2 2814
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
2
xxx = Mod IR3 2815
CO2 CO N2O CnHm CH4 CF4 SF6 H2O
3
xxx = Mod UV1 2830
O3 Cl2 ≤ 5% SO2 NO2
1
xxx = Mod UV1 Cl2 30% na
Cl2 ≤ 30%
1
xxx = Mod UV1 H2S ≤ 5.000 ppm 2841
H2S
1
xxx = Mod UV1 H2S ≤ 1% 2856
H2S
1
xxx = Mod UV2 2831
O3 Cl2 ≤ 5% SO2 NO2
2
xxx = Mod UVRAS 2917
SO2 NO2 NO
3
* Calibration with Propane

Part 4: Casings for Sensor Modules

Assembled according to customer’s specification

Casing Type: 
RITTER MultiGas		 Article
No.		 Casing Type Suitable for
xxx = Cas-2 (1) 2817 Casing Type 2 Multiple modules up to 444 x 305 x 145 mm
xxx = Cas-3 (1) 2818 Casing Type 3 Multiple modules up to 444 x 305 x 189 mm
(1) Casing type depends on the type and number of built-in sensor modules

Part 5: Built‐in Options

Option Type:
RITTER MultiGas		 Article
No.		 Description Range
RMS-O2 (2) (3) 2795 Oxygen Sensor 0 ‐ 25%
2767 Oxygen Sensor 0 – 100%
RMS-O2-resist (3) 2824 Oxygen Sensor
H2S resistant		 0.5 – 35%
RMS-P (2) (3) 2771 Pressure Sensor 800 – 1200 mbar abs.
Resolution <1 mbar
RMS-P-resist (3) 2825 Pressure Sensor
H2S resistant		 0.2 – 3.5 bar abs.
Resolution 2 mbar
RMS-H (2) (3) 2773 Humidity Sensor 0 – 100% RH
RMS-A/O 2648 Analog Voltage Output
0-2 V / 0-5 V / 0-10 V		 4 Analog output ports for 4 separate gas concentrations
16 bit
RMS‐CasHeat 2954 Thermostated Casing Heating and thermostatting of the sensor casing at 50 °C 
(2) Not suitable for SO2, Cl2, H2S
(3) Available as supplement to IR or UV Sensor only

Part 6: Accessories / Options

Option Type:
RITTER MultiGas xxx		 Article
No.		 Description Range
xxx = Cal-ZP-N2 2805 Calibration Gas N2  For zero-point calibration of all gases
xxx = Flow-V 2806 Mini Flow Valve Control of flow rate for calibration gas bottle
Incl. Manometer
xxx = Cal-CG-Cat1 2948 Calibration with special carrier gas (Ar, H2, He) for gases category 1 Category 1 gases:
CO2 CO < 10 Vol-% N2O CnHm CH4 CF4 SF6 O3 CL2 SO2 < 10 Vol-% NO2 NO
xxx = Cal-CG-Cat2 2949 Calibration with special carrier gas (Ar, H2, He) for gases category 2 Category 2 gases:
CO > 10Vol-% SO2 > 10 Vol-% H2S
xxx = Cal-ReCal-Cat1 2950 Recalibration for gases category 1 Category 1 gases:
CO2 CO < 10 Vol-% N2O CnHm CH4 CF4 SF6 O3 CL2 SO2 < 10 Vol-% NO2 NO
xxx = Cal-ReCal-Cat2 2951 Recalibration for gases category 2 Category 2 gases:
CO > 10Vol-% SO2 > 10 Vol-% H2S

Infrared module NDIR Ultraviolet module NDUV

Calibrations

Depending on the number of gases to be analysed, a suitable calibration gas must be selected. Furthermore, the type of gas also influences the optimal calibration gas. Because of the almost infinite number of possible combinations, the following list should therefore only be understood as a first overview.

  • One gas: Calibration in N2
  • Two gases:
    • Binary gas mixture: The sum of the concentrations of both gases is 100%.
      The calibration takes place in the respective other gas »gas in gas« (e.g. CO2 in CH4 or CH4 in CO2).
    • For specific measuring ranges (e.g. CO2 0 – 10 Vol.% and CO 0 – 20 Vol.%), one gas at a time is calibrated in nitrogen N2. The calibration would be carried out in the above example as follows: CO2 10 Vol.% + 90 Vol.% N2 and CO 20 Vol.% + 80 Vol.% N2
  • Three and more gases: The carrier gas dependency of the individual gas components must be checked individually. Then, for example, gas 1 and gas 2 can be defined as binary (and calibrated as »gas in gas«) and gas 3 can be calibrated in N2.

Measurement of Humid Gases

When measuring humid gases, it is essential to prevent condensation of the water vapour inside the sensor. The following diagram shows the maximum water vapour concentration in volume % as a function of temperature at the standard pressure 1013 mbar.

The diagram shows:

  • At room temperature, no condensation occurs up to a maximum humidity of 2 vol.%.
  • Condensation occurs at concentrations above the curve shown.
RITTER MultiGas measurement of humid gases curve

Condensation can be prevented by the following measures:

  • Condensate trap or gas cooler in flow direction in front of the sensor. Please note: This will increase the dead space in front of the sensor.
  • Installation of a heating element with thermostatting in the sensor casing. See Heating and Thermostatting of Sensor Casing. With this heating element, a temperature increase of up to 50 °C is possible. Thus, a condensation can be prevented up to a water vapour concentration of 10 vol.%. Please note: In addition to the heating element, external gas lines/tubes from the gas source to the sensor unit must be heated.

With the optional Humidity Sensor the relative humidity can be measured in the measuring range of 0 ~ 100% rH. Furthermore, the absolute humidity can be measured as well in g/m³. Both values are displayed in the supplied software.

Disadvantages of electrochemical (EC) sensors in comparison to the optical RITTER »MultiGas« Sensors

  • EC sensors become »blind« over time and then display a constant value, usually zero. This suggests misleadingly a stable zero point.
  • EC sensors must therefore be replaced preventatively every 0.5 – 2 years, after replacement the sensor must be recalibrated, as the tolerances of EC sensors are relatively high. This causes additional costs.
  • With EC sensors, mutual influence and deterioration occur by different gases, e.g. NO2 damages the SO2 sensor and vice versa.
  • EC sensors react very strongly to hydrogen. Such sensors are therefore unusable for accurate measurements even at the smallest concentrations of H2 in the gas mixture.
  • In many countries (e.g. in China) EC sensors are forbidden by law for governmental inspection and approval measurements, because these sensors display too low values if they are contaminated or aged. The user then receives »false positive« values.
  • The lifetime of the EC cells is already reduced during storage. Therefore, the storage should only be a few weeks.
  • The response time (t90) is relatively long compared to the optical measuring methods – mostly about 30 sec. Optical systems are in the range < 5 sec.
  • Due to the measuring principle of the EC sensors there is always a chemical reaction between the test gas and the sensor. As a result, small quantities of the test gas components are converted. For example, CO is converted into CO2. With low quantities of test gas, measurements beyond the gas sensor can therefore be influenced because fewer CO molecules are present in the gas sample.

Preventive / Protective Measures with Gas Measurements

a) Additional tube connection for flushing of the casing

The gas lines inside the casing and the measuring cuvette are gas-tight by means of O-rings and other gas-tight connections. However, as with all connections, a leakage rate, however slight, cannot be ruled out. With an additional tube connection for flushing of the casing, an accumulation of the measuring gas inside the casing can be prevented.

In the case of toxic or aggressive gases, a suction line can be connected via this tube connection, which creates a under-pressure inside the housing thus preventing the gas from escaping from the casing.

In case of ignitable gases (methane, hydrogen, etc.), a pressure or suction line can be connected via this tube connection creating an over- or under-pressure inside the casing thus preventing the accumulation of an ignitable gas mixture.

Please note: H2S can be perceived as an unpleasant smell even in the ppb range. Even with an O-ring seal, micro-leaks can occur, which can be extracted by flushing the housing.

b) Heated and thermostatted casing

Condensation of the measuring gas inside of the sensor must be prevented. This can generally be achieved with a condensation trap or gas cooler. Please also refer to Measurement of Humid Gases. Alternatively, the inside of the sensor casing can be heated and thermostatted at 50 °C (standard). The heating not only avoids condensation inside of the sensor but ensures constant measurement results as well. See Heating and Thermostatting of Sensor Casing.

c) Particle filter

Please make sure by use of a suitable filter that no particles are carried into the sensor. These might block the small openings of the internal fittings. It is recommended to use filters of 5 micron or smaller.

Scope of Supply

No. of Items Item
1 Document folder including: Calibration Certificate / Data Sheets / Software Manual
1 Sensor in table top casing
1 Plug-in power supply unit
Input: 100 – 240 V-AC, 50/60 Hz, 0.4 A
Output: 24 V-DC, 0.5 A, 12 W or 36 W (H2S / UVRAS Sensor)
1 Data acquisition software (on USB memory card)
1 Connection cable: Sensor → PC
Standard: USB V2.0 A/B, 1 m
Option: RS232, 3m
3m Viton tubing Øi 4mm/Øo 6mm

Setup

  1. Unpack all items carefully.
  2. Install the data acquisition software according to the »RITTER MultiGas Software Manual«.
    Don’t start the software at this point in time.
  3. Positioning of the sensor:
    1. If the sensor is used in combination of a RITTER MilliGascounter, the sensor must be positioned (in flow direction) in front of the MilliGascounter if this MilliGascounter is filled with HCl solution. Otherwise, the sensor could be damaged by the HCl vapour coming out of the MilliGascounter.
    2. Place the sensor next to the gas source.
      Please note: A tube connection between gas source and sensors that is as short as possible allows a small dead space created by the tubing. In turn, a small dead space enables a fast response time of the sensor.
  4. Connect the power adapter to socket »DC 24 V« at the rear side of the sensor and to mains.
  5. Connect the data acquisition cable to the respective socket at the rear side of the sensor and to the computer:
    1. USB cable to the socket »USB«
    2. RS232 cable to the socket »RS 232« (option)
  6. Connect the gas source to the gas inlet port of the sensor by using the provided tubing as follows:
    1. Remove the screw caps as well as the red rubber caps of the transport lock from the gas inlet and gas outlet.
    2. Slide the screw cap onto the end of the gas inlet tube with the thread of the screw cap facing the tube end.
    3. Push the tube onto the cone in the center of the gas inlet port.
    4. Slide the screw cap on the gas inlet port and screw it in place hand-tight.
  7. If applicable: Connect the gas outlet port of the sensor to other components such as gas sampling bags, exhaust tubing etc. The connection of the tube on the gas outlet port takes place in the same way as described above.
  8. Switch-on the power switch at the front side of the sensor casing.
  9. Start the software and open the COM port(s) of the connected sensor module(s) according to the software manual.

The RITTER »MultiGas« Sensor is now ready for use.

Infrared Sensors

MultiGas Infrared Module NDIR

Description

Gas analysis based on the NDIR technique is an established method to determine the concentrations of gases in complex mixtures. The RITTER »MultiGas« sensors use new optical components for optimal analysis results: Up to 3 optical filters analyse the gas which flows through the sensor as one gas stream. The optional oxygen, pressure, and humidity sensors are in-line with the same single gas stream.

The individual internal modules are sealed by means of O-ring connections.

In order to achieve an optimum adaptation to the required measuring range, the lengths of the modular measurement cells (= cuvettes) can be implemented in the range of 5 mm (large measurement range in percentage level) up to 250 mm (small measurement range in ppm level).

Cuvettes with a length ≥ 20 mm are coated with a resistant gold layer in order to improve the reflection properties for low concentration level detection. Cuvettes used with aggressive gases are gold-coated as well.

The other internal mechanical parts are made out of aluminium, optionally out of stainless steel.

For fast response applications the measuring system delivers a stable result within t90 ≈ 3 seconds.

The entire unit can be disassembled for easy maintenance/service.

Applications

  • Biogas analysis
  • Natural gas analysis
  • Environmental and Process Measurement
  • TOC analysers
  • Continuous Emission Monitoring (CEM)
  • Elemental analysis
  • Industrial gas analysis

Specifications

General features
Measurement technology: Innovative NDIR Sensor (non-dispersive infrared sensor)
Detectable gases:
CO2 CO CO > 10Vol-% CO < 10 Vol-% N2O CnHm CH4 CF4 SF6 H2O
Number of simultaneously detectable gases: max. 3 per sensor unit
Measurement ranges: See Table of Measurement Ranges
Flow rate range: 5 ~ 300 ltr/h
For higher flow rates the sensor can be operated in bypass
Max. gas inlet pressure: 300 mbar
Pressure loss (without additional optional sensors): 10 @ 100 / 35 @ 200 / 70 @ 300 (mbar @ ltr/h)
Temperature compensation: Yes
Data acquisition software: Yes
Lifetime of IR radiation source: > 40 000 h
Measurement cuvette: Aluminium, with measurement ranges ≤1% gold-plated inside
Cuvette sealing: Viton O-ring
Casing: High-quality table-top casing, aluminium
Dimensions (W x H x L): 171 x 86 x 290 mm
Weight: approx. 2 kg
Gas connections: PVDF screw-type tube connection for tube Øi 4 mm, Øo 6 mm
Measuring response
Linearity error: < ± 1% F.S.
Repeatability: ± 0.5% F.S.
Long term stability zero: < ± 2% F.S. / week
Long term stability span: < ± 2% F.S. / month
Temperature influence of zero point: < 1% F.S. / 10K
Temperature influence of span: < 2% F.S. / 10K
Cross sensitivity: < 2% F.S.
Pressure influence: < 1.5% / 10hPa of reading
Warm-up time: 2 min
Response time (t90): ≈ 3 sec
Sampling frequency by software: ≤ 10 Hz
Detection limit: See Table of Detection Limits
Resolution: 0.5 x detection limit
Water vapour: No influence with measurements of CO2 and CH4
Electrical features
Power supply: 24 VDC incl. power plug 100 ~ 240 VAC
50/60 Hz: 24 VDC
Average power consumption: < 1W
Interface: USB (standard), RS232 / CANbus / CANopen (options)
incl. data transmission cable 1 m
Analogue voltage output (option): 0 – 2 V / 0 – 5 V / 0 – 10 V
Climatic conditions
Operating temperature: +15 ~ +45 °C
Storage temperature: –20 ~ +60 °C
Operating pressure: 800 ~ 1200 hPa (mbar)
Ambient humidity: 0 ~ 95% rel. humidity
Condensing inside of sensor must be prevented!

* Analysis of CnHm: The calibration of sensors for CnHm will be performed with propane. Aromatic hydrocarbons are also measured but with a different weighting. This means that the sensitivity of the sensor is significantly smaller with these gases than with other hydrocarbons.

List of standard measurement ranges *1 ( and detection limits *2 )

Standard Measuring Ranges with respective Detection Limits ( % of F.S. *3 )
100
Vol.%		 50
Vol.%		 30
Vol.%		 20
Vol.%		 10
Vol.%		 5
Vol.%		 1
Vol.%		 5,000
ppm		 2,000
ppm		 1,000
ppm		 500
ppm		 300
ppm		 100
ppm		 50
ppm		 10
ppm		 1
ppm
CO2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.3%)
(< 0.3%)
CO
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.3%)
(< 0.5%)
(< 0.5%)
N2O
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.3%)
CnHm*4
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.2%)
(< 0.5%)
(< 0.5%)
CH4
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.3%)
(< 0.5%)
CF4
(< 0.2%)
(< 0.2%)
(< 0.2%)
SF6
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.5%)
(< 0.3%)
(< 0.3%)
H2O
*1 A standard measurement range is defined by / *2  (= 3 σ) in Percent of Full Scale / *3 F.S. = Full Scale / *4 Calibration with Propane

Infrared module NDIR Ultraviolet module NDUV

Definition of Detection Limit

The Detection Limit is the smallest measurement value which can be obtained with a specific uncertainty. This uncertainty includes the resolution, noise and stability of the gas sensor for a specific gas and specific measurement range. For evaluation of the detection limit value, several single measurements are taken at the identical measurement conditions. With the obtained single measurement results the standard deviation “Sigma” (σ) is calculated. The values given in the table equal the triple amount of Sigma.

Recalibrations

The following recalibration intervals are recommended for IR sensors:

  • Zero-point: Weekly with inert gas, e.g. Nitrogen
    The recalibration of the zero point is described in the software manual.
  • End-point (full scale): Every 3 months with suitable calibration gas

Ultraviolet Sensors

MultiGas Ultraviolet Module NDUV

Description

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.

The entire unit can be disassembled for easy maintenance/service.

The individual internal modules are sealed by means of O-ring connections.

In order to achieve an optimum adaptation to the required measuring range, the lengths of the modular measurement cells (= cuvettes) can be implemented in the range of 5 mm (large measurement range in percentage level) up to 250 mm (small measurement range in ppm level).

Cuvettes with a length ≥ 20 mm are coated with a resistant gold layer in order to improve the reflection properties for low concentration level detection. Cuvettes used with aggressive gases are gold-coated as well.

The internal mechanical parts are made out of aluminium, optionally out of stainless steel.

For fast response applications the measuring system delivers a stable result within t90 ≈ 1-2 seconds.

Applications

  • Biogas analysis
  • Natural gas analysis
  • Environmental and Process Measurement
  • TOC analysers
  • Continuous Emission Monitoring (CEM)
  • Elemental analysis
  • Industrial gas analysis

Specifications

General features
Measurement technology: Innovative NDUV Sensor
(non-dispersive ultraviolet sensor)
Detectable gases:
Number of simultaneously detectable gases:  max. 2
Measurement ranges: See Table of Measurement Ranges
Flow rate range: 5 ~ 300 ltr/h
For higher flow rates the sensor can be operated in bypass
Max. gas inlet pressure: 300 mbar
Pressure loss (without additional optional sensors):  10 @ 100 / 35 @ 200 / 70 @ 300 (mbar @ ltr/h)
Temperature compensation:  Yes
Data acquisition software:  Yes
Lifetime of UV radiation source:  > 8 000 h
Measurement cuvette: Stainless steel with silicone coating inside
Cuvette sealing:  Viton O-ring
Internal tubing:  FKM / Viton (fluorinated rubber)
Casing:  High-quality table-top casing, aluminium
Dimensions (W x H x L):  464 x 189 x 305 mm
Weight:  approx. 6.5+ kg
Gas connections:  PVDF screw-type tube connection for tube Øi 4 mm, Øo 6 mm
Measuring response
Linearity error:  < ± 1% F.S.
Repeatability:  ± 0.5% F.S.
Long term stability zero:  < ± 1% F.S. / 24 h
Long term stability span:  < ± 1% F.S. / month
Temperature influence of zero point:  < 1% F.S. / 10K
Temperature influence of span: < 2% F.S. / 10K
Cross sensitivity: < 2% F.S.
Pressure influence:  < 1.5% / 10 hPa of reading
Warm-up time:  1 min (initial), < 60 min for full specification
Response time (t90): 1.5 – 15 sec
Sampling frequency by software:  ≤ 10 Hz
Detection limit:  See Table of Detection Limits
Resolution:  0.5 x detection limit
Electrical features
Power supply:  24 VDC incl. power plug 100 ~ 240 VAC
50/60 Hz: 24 VDC
Supply current (peak) < 0.4 A
Average power consumption < 7.5 W
Interface: USB (standard)
RS232 / CANbus / CANopen (options)
incl. data transmission cable 1 m
Analogue voltage output (option):  0-2 V / 0-5 V / 0-10 V
Climatic conditions
Operating temperature:  +25 ~ +45 °C
Storage temperature:  –20 ~ +60 °C
Operating pressure:  800 ~ 1200 hPa (mbar)
Ambient humidity: 0 ~ 95% rel. humidity
Condensing inside of sensor must be prevented!

List of standard measurement ranges *1 ( and detection limits *2 )

Standard Measuring Ranges with respective Detection Limits ( % of F.S. *3 )
100
Vol.%		 50
Vol.%		 30
Vol.%		 20
Vol.%		 10
Vol.%		 5
Vol.%		 1
Vol.%		 5,000
ppm		 2,000
ppm		 1,000
ppm		 500
ppm		 300
ppm		 100
ppm		 50
ppm		 10
ppm		 1
ppm
O3
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.5%)
(< 0.5%)
(< 0.5%)
CL2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.5%)
SO2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.5%)
(< 0.5%)
(< 0.5%)
H2S
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.5%)
NO2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.2%)
(< 0.5%)
(< 0.5%)
(< 0.5%)
NO
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.2%)
*1 A standard measurement range is defined by / *2  (= 3 σ) in Percent of Full Scale / *3 F.S. = Full Scale / *4 Calibration with Propane

Infrared module NDIR Ultraviolet module NDUV

Definition of Detection Limit

The Detection Limit is the smallest measurement value which can be obtained with a specific uncertainty. This uncertainty includes the resolution, noise and stability of the gas sensor for a specific gas and specific measurement range. For evaluation of the detection limit value, several single measurements are taken at the identical measurement conditions. With the obtained single measurement results the standard deviation “Sigma” (σ) is calculated. The values given in the table equal the triple amount of Sigma.

Recalibrations

The following recalibration intervals are recommended for UV sensors:

  • Zero-point:
    • Concentrations < 300 ppm: Every 48 hours with inert gas, e.g. Nitrogen
    • Concentrations ≥ 300 ppm: Every 24 hours with inert gas, e.g. Nitrogen
      The recalibration of the zero point is described in the software manual.
  • End-point (full scale): Every 3 months with suitable calibration gas

MultiGas Ultraviolet Module NDUV / UVRAS

Description

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).

Applications

  • Automotive test equipment
  • Portable Gas Analysis (PEMS)
  • Exhaust gas monitoring (CEM)
  • Laboratory area
  • Industrial gas analysis
  • Continuous Emission Monitoring (CEM)
  • Automotive exhaust gas analysis

Specifications

General features
Measurement technology:  UV resonance absorption spectroscopy (UVRAS)
Detectable gases: 
SO2 NO2 NO
Number of simultaneously detectable gases:  max. 3 per sensor unit
Measurement ranges: See Table of Measurement Ranges
Flow rate range:  5 ~ 300 ltr/h
For higher flow rates the sensor can be operated in bypass
Max. gas inlet pressure: 300 mbar
Pressure loss (without additional optional sensors):  10 @ 100 / 35 @ 200 / 70 @ 300 (mbar @ ltr/h)
Temperature compensation:  Yes
Data acquisition software:  Yes
Lifetime of UV radiation sources: LED > 20 000 h (NO2, SO2)
EDL > 8 000 h (NO)
Measurement cuvette: Stainless steel with silicone coating inside
Cuvette sealing: Viton O-ring
Internal tubing: FKM / Viton (fluorinated rubber)
Casing:  High-quality table-top casing type 2, aluminium
Dimensions (W x H x L):  464 x 189 x 305 mm
Weight:  approx. 6.5+ kg
Gas connections:  PVDF screw-type tube connection for tube Øi 4 mm, Øo 6 mm
Measuring response
Linearity error: < ± 1% F.S.
Repeatability: ± 0.5 % F.S.
Long term stability zero: < 3 ppm / 24 h
Long term stability span: < ± 1 % F.S. / month
Temperature influence of zero point: < 1 % F.S. / 10 K
Temperature influence of span: < 2 % F.S. / 10 K
Cross sensitivity: 500 ppm NO2 < 2 ppm
100 ppm SO2 < 2 ppm
100 ppm N2O < 10 ppm
20 °C D.P. H2O < 10 ppm
Pressure influence:  < 1.5% / 10 hPa of reading
Warm-up time:  1 min (initial), < 60 min for full specification
Response time (t90):  1.5 ~ 15 sec
Sampling frequency by software:  ≤ 10 Hz
Detection limit:  See Table of Detection Limits
Resolution:  0.5 x detection limit
Electrical features
Power supply:  24 VDC incl. power plug 100 ~ 240 VAC
50/60 Hz: 24 VDC
Supply current (peak):  1.5 A
Inrush current:  0.2 ~ 0.7 A
Power consumption:  36 W
Interface:  USB (standard)
RS232 / CANbus / CANopen (options)
incl. data transmission cable 1 m
Analogue voltage output (option):  0-2 V / 0-5 V / 0-10 V
Climatic conditions
Operating temperature: +5 ~ +40 °C
Storage temperature:  –20 ~ +60 °C
Operating pressure:  800 ~ 1200 hPa (mbar)
Ambient humidity: 0 ~ 95% rel. humidity
Condensing inside of sensor must be prevented!

List of standard measurement ranges *1 ( and detection limits *2 )

Standard Measuring Ranges with respective Detection Limits ( % of F.S. *3 )
100
Vol.%		 50
Vol.%		 30
Vol.%		 20
Vol.%		 10
Vol.%		 5
Vol.%		 1
Vol.%		 5,000
ppm		 2,000
ppm		 1,000
ppm		 500
ppm		 300
ppm		 100
ppm		 50
ppm		 10
ppm		 1
ppm
SO2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.5%)
(< 0.5%)
(< 0.5%)
NO2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.2%)
(< 0.5%)
(< 0.5%)
(< 0.5%)
NO
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.2%)
*1 A standard measurement range is defined by / *2  (= 3 σ) in Percent of Full Scale / *3 F.S. = Full Scale / *4 Calibration with Propane

Infrared module NDIR Ultraviolet module NDUV

Definition of Detection Limit

The Detection Limit is the smallest measurement value which can be obtained with a specific uncertainty. This uncertainty includes the resolution, noise and stability of the gas sensor for a specific gas and specific measurement range. For evaluation of the detection limit value, several single measurements are taken at the identical measurement conditions. With the obtained single measurement results the standard deviation “Sigma” (σ) is calculated. The values given in the table equal the triple amount of Sigma.

Recalibrations

The following recalibration intervals are recommended for UV sensors:

  • Zero-point:
    • Concentrations < 300 ppm: Every 48 hours with inert gas, e.g. Nitrogen
    • Concentrations ≥ 300 ppm: Every 24 hours with inert gas, e.g. Nitrogen
      The recalibration of the zero point is described in the software manual.
  • End-point (full scale): Every 3 months with suitable calibration gas

MultiGas Ultraviolet Module NDUV / H2S

HXXO20220803182503 2560

Description

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.

In contrast to photometric NDUV sensors the lifetime of  electrochemical sensors for measurement of H2S is limited. Please note that lifetime data for such sensors are given for air and not for measurement of H2S. For H2S concentrations > 200 ppm the lifetime is reduced, for concentrations > 1000 ppm critical. While the measurement performance of UV-LED is constant, EC sensors are becoming »deaf«.

Applications

  • Biogas analysis
  • Environmental and Process Measurement
  • Leakage detection
  • Industrial gas analysis
  • Renewable Gas Monitoring

Specifications

General features
Measurement technology: Innovative NDUV Sensor
(non-dispersive ultraviolet sensor)
Dual beam
Detectable gases:
SO2 H2S
Number of simultaneously detectable gases: max. 2
Measurement ranges: See Table of Measurement Ranges
Flow rate range: 5 ~ 300 ltr/h
For higher flow rates the sensor can be operated in bypass
Max. gas inlet pressure: 300 mbar
Pressure loss (without additional optional sensors): 10 @ 100 / 35 @ 200 / 70 @ 300 (mbar @ ltr/h)
Temperature compensation: Yes
Data acquisition software: Yes
Lifetime of UV radiation source: > 8 000 h
Measurement cuvette: Stainless steel with silicone coating inside
Cuvette sealing: Viton O-ring
Internal tubing: FKM / Viton (fluorinated rubber)
Casing: High-quality table-top casing, aluminium
Dimensions (W x H x L): 300 x 100 x 81 mm
Weight:  approx. 1670 g
Gas connections: PVDF screw-type tube connection for tube Øi 4 mm, Øo 6 mm
Measuring response
Linearity error: < ± 1% F.S.
Repeatability: ± 0.5% F.S.
Long term stability zero: < ± 1% F.S. / 24 h
Long term stability span: < ± 1% F.S. / month
Temperature influence of zero point: < 1% F.S. / 10K
Temperature influence of span: < 2% F.S. / 10K
Cross sensitivity: < 2% F.S.
Pressure influence: < 1.5% / 10 hPa of reading
Warm-up time: 1 min (initial), < 15 min for full specification
Response time (t90): 1.5 – 15 sec
Sampling frequency by software: ≤ 10 Hz
Detection limit: See Table of Detection Limits
Resolution: 0.5 x detection limit
Electrical features
Power supply:  24 VDC incl. power plug 100 ~ 240 VAC
50/60 Hz: 24 VDC
Supply current (peak): < 0.4 A
Average power consumption: < 7.5 W
Interface: USB (standard)
RS232 / CANbus / CANopen (options)
incl. data transmission cable 1 m
Analogue voltage output (option):  0-2 V / 0-5 V / 0-10 V
Climatic conditions
Operating temperature:  +5 ~ +45 °C
Storage temperature:  –20 ~ +60 °C
Operating pressure:  800 ~ 1200 hPa (mbar)
Ambient humidity: 0 ~ 95% rel. humidity
Condensing inside of sensor must be prevented!

List of standard measurement ranges *1 ( and detection limits *2 )

Standard Measuring Ranges with respective Detection Limits ( % of F.S. *3 )
100
Vol.%		 50
Vol.%		 30
Vol.%		 20
Vol.%		 10
Vol.%		 5
Vol.%		 1
Vol.%		 5,000
ppm		 2,000
ppm		 1,000
ppm		 500
ppm		 300
ppm		 100
ppm		 50
ppm		 10
ppm		 1
ppm
SO2
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.5%)
(< 0.5%)
(< 0.5%)
H2S
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.1%)
(< 0.2%)
(< 0.5%)
*1 A standard measurement range is defined by / *2  (= 3 σ) in Percent of Full Scale / *3 F.S. = Full Scale / *4 Calibration with Propane

Infrared module NDIR Ultraviolet module NDUV

Definition of Detection Limit

The Detection Limit is the smallest measurement value which can be obtained with a specific uncertainty. This uncertainty includes the resolution, noise and stability of the gas sensor for a specific gas and specific measurement range. For evaluation of the detection limit value, several single measurements are taken at the identical measurement conditions. With the obtained single measurement results the standard deviation “Sigma” (σ) is calculated. The values given in the table equal the triple amount of Sigma.

Recalibrations

The following recalibration intervals are recommended for UV sensors:

  • Zero-point:
    • Concentrations < 300 ppm: Every 48 hours with inert gas, e.g. Nitrogen
    • Concentrations ≥ 300 ppm: Every 24 hours with inert gas, e.g. Nitrogen
      The recalibration of the zero point is described in the software manual.
  • End-point (full scale): Every 3 months with suitable calibration gas

Options (installed inside of the sensor casing)

Oxygen Sensor

HXXO20230311162653PEX 2560

Overview

  • 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: 0.1 Vol.%
  • Response time (t90): ≈ 5 – 10 s; automotive version < 3.5 s
  • Lifetime: approx. 5 years

The oxygen sensor is a sensor module available as option in addition to a RITTER »MultiGas« NDIR or NDUV sensor. The measured oxygen concentration is displayed in the provided software. The sensor is built into the casing of the RITTER »MultiGas« sensors.

The following versions are available:

  • Standard version suitable for non-aggressive gases
  • H2S and similar acidic gases resistant version

Specifications

General features
VersionStandard versionH2S resistant version
Measurement range0 – 25 Vol.% O20 – 100 Vol.% O20.5 – 35 Vol.% O2
ApplicationBiogas, Automotive exhaust gas analyserIndustrial, fully CO2 resistantIndustrial, fully CO2 resistant,
shows high resistance to acid gases
Medium contact materialsABS, FKM, PPS, PTFE, stainless steelABS, PVC, PPS, PTFE, stainless steelABS, PVC, PPS, PTFE,
stainless steel
Expected operating life1,000,000 Vol.% O2 h~ 1,200,000 Vol.% O2 h~ 1,200,000 Vol.% O2 h
Sensor lifetime4 years at ambient air,
depending on application		6 years at ambient air,
depending on application		6 years at ambient air
Dimensions
(H x W x L)		65.4 mm × 31.7 mm × 56.6 mm
Weight70 g
Tube connector4/6 mm tube
Measuring response *
VersionStandard versionH2S resistant version
Measurement range0 – 25 Vol.% O20 – 100 Vol.% O20.5 – 35 Vol.% O2
Resolution0.1 Vol.%0.1 Vol.%0.1 Vol.%
Response time (t90)< 3.5 s< 10 s< 5 s
Drift **< 1% per month< 1% per month< 3% per month
Linearity Error0 – 2 Vol.% O2: ± 0.1 abs.
2.1 – 100 Vol.% O2: ± 0.05 rel.		0 – 2 Vol.% O2: ± 0.1 abs.
2.1 – 35 Vol.% O2: ± 0.05 rel.
Repeatability ***± 1 Vol.% O2± 1 Vol.% O2
Influence of Humidity–0.03 % rel. O2 reading /
% RH		–0.03 % rel. O2 reading /
% RH		–0.03 % rel. O2 reading /
% RH
InterferencesCO2: up to 20 Vol.%
CO: up to 2000 ppm
NOx: up to 5000 ppm
HC: up to 5000 ppm
N2O: up to 500 ppm		< 20 ppm O2 response to:
100 Vol.% CO
100 Vol.% CO2
100 Vol.% C3H8
3000 ppm NO in N2
1000 ppm C6H6 in N2
500 ppm SO2 in N2
< 100 ppm O2 response to:
3000 ppm C2H6O
3000 ppm C4H10S
< 200 ppm O2 response to:
3000 ppm C2H6S2
< 400 ppm O2 response to:
100 Vol.% H2
< 500 ppm O2 response to:
2000 ppm H2S in N2		< 20 ppm O2 response to:
100 Vol.% CO
100 Vol.% CO2
100 Vol.% C3H8
1000 ppm C6H6 in N2
2000 ppm H2S in N2
< 20000 ppm O2 response to:
3000 ppm NO in N2
1000 ppm H2 in N2
500 ppm SO2 in N2

* related to Pa = 1013 hPa, Ta = 25 °C, RH = 50%, flow = 2.5 l/min
** averaged across 12 months
*** @ 100 Vol.% O2 applied for 5 min

Climatic conditions
VersionStandard versionH2S resistant version
Measurement range0 – 25 Vol.% O20 – 100 Vol.% O20.5 – 35 Vol.% O2
Operating temperature0 – 40 °C
intermittent 40 – 50 °C		0 – 45 °C0 – 50 °C
Storage temperature-20 – 40 °C
5 – 25 °C recommended
40 – 50 °C max. 1 week		5 – 30 °C recommended
-20 – 50 °C maximum
Air pressure650 – 1250 hPa (mbar)700 – 1250 hPa (mbar)600 – 1250 hPa (mbar)
Ambient humidity0 – 95% rel. humidity (not condensing)

Pressure Sensor

HXXO20220804152150PE 2560 2

Overview

A change in the gas and/or atmospheric pressure causes a change in the number of molecules per volume and thus a change in gas density. This density change in turn has a significant influence on the result of the concentration measurement by the sensor. By measuring the gas pressure inside of the sample cell (cuvette), the value of the concentration measurement is compensated / corrected.

The pressure sensor enables an increase in the accuracy of the gas analysis measurement by a factor of 15:

  • Without pressure sensor: ±1.5% per pressure difference of 10 hPa
  • With pressure sensor: ±0.1% per pressure difference of 10 hPa

The pressure sensor is a sensor module available as option in addition to a RITTER »MultiGas« NDIR or NDUV sensor. The sensor is built into the casing of the RITTER »MultiGas« sensors. The measured pressure value is displayed in the provided software.

Specifications

For non-aggressive gases:

  • Pressure compensation of measured gas concentrations
  • Measuring range: 800 – 1,200 mbar abs.
  • Measurement accuracy: ±1% of span (full scale)
  • Resolution: <1 mbar
  • Response time (t90): 1 s
  • Incl. temperature compensation

For H2S and similar acid gases:

  • Pressure compensation of measured gas concentrations
  • Measuring range: 0.2 – 3.5 bar abs.
  • Measurement accuracy: ±1% of span (full scale)
  • Resolution: 2 mbar
  • Response time (t90): 1 s
  • Incl. temperature compensation

Humidity Sensor

HXXO20190220180649 1200

Overview

The humidity sensor is a sensor module available as option in addition to a RITTER »MultiGas« NDIR or NDUV sensor. The sensor is built into the casing of the RITTER »MultiGas« sensors. The measured humidity values (absolute and relative) are displayed in the provided software.

Specifications

  • 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 (in software): absolute and relative humidity (% absH) / (% rH)

Analog Voltage Output

RITTER A

Overview

The Analog Voltage Output Module allows the simultaneous output of up to 4 different values 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

Technical Data

For connection to an analog data acquisition device the analog voltage output port alternatively provides the following voltage levels:

  • 0 – 2 V
  • 0 – 5 V
  • 0 – 10 V

The voltage range is pre-set according to the order and cannot be changed by the user.

Please note the assignments of the respective gas concentration measurements to the respective channels. These assignments are stated in the Calibration Protocol of the sensor unit.

Assignment of contacts to the channels of the gas concentration measurements at the socket and plug of the Analog Voltage Output:

image003
View to socket
image002
View to plug
Contact No. Assignment to channel Wire Colors of provided Connection Cable
1 channel 1 white
2 channel 2 green
3 channel 3 yellow
4 channel 4 grey
5 ground brown

Analogue output signals of oxygen and humidity sensors:

  • NDIR sensors: Channel 4 (grey wire)
  • NDUV sensors: Channel 2 (green wire)

The connection cable is delivered with open wires to be connected to the analog data acquisition device of the user. The wire colours are listed in the above table.

Heating and Thermostatting of Sensor Casing

HXXO20190220180208 1600

Overview

In order to avoid condensation of humid gas inside of the sensor, the sensor and sensor casing can be heated and thermostatted. By default, the temperature controller is preset to 50 °C; lower temperatures are possible on request.

The heating element and temperature controller are mounted at the support of the measurement cuvette.

Features

  • Temperature controller: 30 – 50 °C
  • Control accuracy: ± 0.2 K
  • Heating power: 12 Watt