D-R 290

Optical opacity / dust monitor 2nd generation

The D-R 290 has been used successfully for more than 15 years in various applications as reliable and low maintenance opacity / dust monitor. Now the new generation is available.

The D-R 290 is a certified optical transmission monitor to measure the opacity or dust concentration of flue gases with medium to high dust concentrations.

The D-R 290 operates using the double-pass method according to the auto-collimation principle. The light beam traverses the measuring path twice. The attenuation of the light beam by the dust content in the measuring section is measured and evaluated.


  • Continuous and contactless measurement
  • Automatic zero and span check
  • Automatic measurement and correction of contamination of optical surfaces
  • Extremely powerful and stable super-wide band diode (SWBD) light source
  • Extremely low-maintenance
  • Fail-safe shutters with purge air monitoring as option
  • Certified according to EN 15267-3
  • Compliant with US EPA 40 CFR 60 PS1 and ASTM 6216


Advantages of the new generation

  • Digital Modbus interface according to VDI 4201-3
  • Convenient operation with remote access option
  • All settings can be changed without opening the device
  • Compatible with universal display and control unit D-ISC 100


Suitable for dust concentration measurement

  • on incineration plants
  • on power plants
  • on cement plants
  • in the metal industry
  • on plants according to IED 2010/75/EC
  • on converter plants and asphalt mixing plants
  • on plants for the incineration of biomass


Suitable for measuring the opacity of flue gas

  • on plants in accordance with U.S. EPA 40 CFR 60 PS1, special MCOC required
  • on cruise and container ships


Suitable for measurement of dust load in warehouses

Technical Data

Sample gas typeAir, flue gas, non flammable process gas
Sample gas temperatureAbove dew point up to 250 °C (482 °F) standard,
optional up to 1000 °C (1832 °F)
Inner duct pressure-50...+20 hPa (optional higher)
Sample gas relative humidity0...95% RF, non-condensing
Stack/duct inner diameter1…18 m (3.3…59.1 ft)
Measuring principleMeasuring the optical transmission of visible light which passed a measuring path twice.
ConformitiesIED 2010/75/EU
EN 13284-2, EN 14181
EN 15267-3
40 CFR 60 US EPA PS1
40 CFR 60 US EPA PS11
CertificatesCE, COC QAL1 DIN EN 14181 / DIN EN ISO 14956 / EN 15267-3, MCERTS, Pattern Approval GOST R, Pattern Approval certificate Rep.of Belarus, Pattern Approval Certificate PRC, MCOC 40CFR 60 EPA PS1
Measuring locationIn-situ, non-contact
Self-check, protective functionsAutomatic zero- and span check
Automatic soiling correction
LED light source: no readjustment needed
Automatic fail safe shutter in case of purge air failure (option)
System componentsD-R 290 M xx2 measuring head
D-R 290 R xx2 reflector
D-ISC 100 Universal operating and display unit
D-BL purge air unit
D-R 290 E mounting flange with tube
D-SK fail safe shutter (option)
Physical measuring valueOptical density/ extinction, opacity
Derived measuring valuesTransmission, opacity (SP), extinction, dust concentration in mg/m3, mg/Nm3 (after gravimetric calibration)
Measuring range opacity0...20% ... 0…100%
Output range opacityFreely programmable
Measuring range extinction0…0.1 ... 0...2.0
Output range extinctionFreely programmable within the measuring range
Measuring range dust concentration0…10000 mg/m3 (depending on calibration)
Output range dust concentrationFreely programmable within the measuring range
Lowest detection limit0.75% for measuring range 0...0.1 extinction
Combined standard uncertainty acc. to QAL1, DIN EN 141811.8%, related to the certified measuring end value 15mg/m3
Light source, spectral range450…680 nm, SWBD LED white
Process connectionConnection flange, bolt circle 100 mm, tube ID = 59 / 83 / 105 mm
Digital interfacesRS 485 Modbus RTU, bi-directional communication
Mini-USB (service)
Analog outputs1x 4-20 mA, 400 Ohm, potential free, assignment programmable
Digital outputs2x contact NC/NO, max. load 60 VDC /
30 VAC / 0.5 A
assignment programmable, typically: maintenance, failure
Power supply24 VDC, 0.5 A
Ambient temperature (operational)-40…+60 °C (-40…140 °F)
IP protection class (IEC 60529)IP65
EX zoneOption: Ex II 3G Ex pz II T4, Ex II 2G Ex px II T4
Dimensions (hxwxd)370 x 190 x 400 mm
Weight10 kg
MaterialAluminum, painted blue RAL 5017
Process connectionConnection flange, bolt circle 100 mm, tube ID = 59 / 83 / 105 mm
Ambient temperature (operational)-40…+60 °C (-40…140 °F)
IP protection class (IEC 60529)IP65
Dimensions (HxWxD)370 x 190 x 270 mm
Weight7 kg
MaterialAluminum, painted blue RAL 5017
Power supply115 / 230 VAC, 50 / 60 Hz, others on request
Power consumption0.37 kW (50 Hz) / 0.43 kW (60 Hz)
Air supply capacity40 m3/h (50 hPa) / 60 m3/h (25 hPa), others on request
Ambient temperature (operational)-20…+50 °C (-4…122 °F), optional higher
IP protection class (IEC 60529)IP55
Dimensions (HxWxD)480 x 450 x 320 mm
Weight12 kg
MaterialStainless steel 1.4301
  • The suitability of the D-R 290 for the listed ranges depends on the kind of dust, the size distribution and the duct diameter.
  • Subject to technical modifications.


Universal display and operating units

The universal operating unit  Opens internal link in new windowD-ISC 100 allows the connection of several DURAG devices. It allows parameterisation and maintenance of all connected devices via integrated keypad or a connected PC and also supports remote access via intranet or internet connection.


Our  Opens internal link in new windowD-ESI Service and Parameterisation Software  assists you to manage all your DURAG sensors connected in one network system via a uniform graphical Interface.


Please contact your sales representitive for more Information.

Supply unit

  • D-TB x00 in various versions
  • for voltage supply of one DURAG sensor
  • different housings available

Please contact your sales representitive for more information.

Purge air blower

  • D-BL xx in various versions
  • for supplying the measuring head with purge air
  • weather protection cover available as an option

Please contact your sales representitive for more information.

We offer various accessories such as weather protection covers for your sensor, reference filter sets, mounting flanges and so on to fit your application and to have all components from one source.

Please contact your sales representative for further information.

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