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Opacity Dust Monitor

Opacity Dust Monitor
Product Code : DSL330
Product Description

We have been engaged in manufacturing and supplying the best grade array of Opacity Dust Monitor since our commencement in the domain. This monitor is manufactured under the strict surveillance of ingenious team members using premium grade components and progressive techniques in adherence with preset industry norms. This monitor is widely applauded to be used for determining the presence of dust particles in gases flowing through ducts, flue, stacks etc. Moreover, our clients can avail this Opacity Dust Monitor in multitude of technical specifications at budget-friendly prices.

Key points:
  • Clear display to show readings in mg/m�
  • Facilitated with automatic zero and calibration check feature
  • Allows easy relocation and installation
  • Inbuilt software for result storage, control and data logging

The Double Pass Particulate Monitor DSL-330 Particulate Monitor is an optical instrument designed to measure the concentration of dust or particulate matter in an exhaust gas passing through a duct, stack or flue. The DSL-330 uses the double pass light transmission measurement technique, with a folded beam Transceiver/Reflector arrangement. A light beam emitted from the Transceiver (TRX) passes across the duct, stack or flue to a Reflector, which then returns the light to the Transceiver where the intensity of the received light is measured. Increased particulate density in the stack gas attenuates the transmitted light and causes the intensity of the
received light to fall. When calibrated against standard reference measurements, this reduction in intensity can be used to calculate the particulate concentration and present a reading in mg/m3.


  • In situ measurement directly in exhaust gas flow
  • Measurement reading as particulate as mg/m3
  • Modulated green LED source for long lifetime stability and immunity to ambient light
  • Rugged 316 stainless steel construction
  • In-situ zero and calibration check facility
  • Choice of interface options enabling easy integration
  • Free utility software for PC based set-up, control and data logging
  • Optional Operator Interface with different mounting configurations

Technical specification



Measuring Principle

Light Transmission

Operating Wavelength

510 – 540 nm (green LED)

Measurement Reading

Concentration (mg/m3)

Measuring Range

0 – 1000 mg/m3 (user configurable)

Path Length (duct diameter)

0.5 – 10 m (flange-to-flange separation)


+ / - 2 %


0.1 mg/m3 (display resolution)


1 – 60 s (user selectable)

Drift with Temperature

+ / - 2 % (over 20 °C)



+24 Vdc (optional 90-260 Vac PSU available)

Nominal Current Consumption

400 mA

Power Up Current Consumption

400 mA

Purge Air Supply Volume

50 – 200 L/min (to each air purge body)

Purge Air Quality

Suitably filtered, oil free and dry


Serial Comms

ModBus RTU via RS485
Internal USB (OI)
External USB (TRX)

Analogue Outputs

4.0 – 20 mA (isolated and scalable)

Relay Contacts

3 A @ 30 Vdc (signal level and service alarms)


Ambient Operating Temperature

-20 – +55 °C (air temperature around the equipment)

Exhaust Gas Temperature

Up to +600 °C (heat insulating gaskets included)

Ambient Operating Humidity

0 – 100 %

Ingress Protection

IP65 for external use


316 Stainless Steel (powder coated)


153 x 120 x 122 mm (measuring head)


2.5 kg per head

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