Emission Monitor model EM919 is an indigenous product for measuring dust concentration. This device operates on the principle of optical transmissometry, using single pass of a divergent light beam. It can be installed directly on the outlet stack. The dust concentration is measured depending upon the amount of light blocked by suspended articles in exhaust gas. Advanced techniques are effectively used to detect & compensate for errors due to ambient light as well as stationary dust giving accurate emission readings. Unique design of Swirling Chamber ensures effective cleaning of lenses. Due to its unique algorithm of time-based accumulation of opacity, the EM919 can give emission per normalized gas volume (i.e. in mg/Nm3)


  • In-situ measurement
  • Real time operation
  • High intensity Red LED transmitter which
    • Eliminates error of steam
    • Leads to Effective detection of the ambient light
  • Effective detection of stationary dust on the lens
  • Single pass diverging beam
  • Immune to minor alignment variations
  • State-of-the-art microprocessor technology
  • Reading in mg/Nm3
  • Calibration check for every reading
  • Maintenance alarm if excessive dust coating on lenses.
  • Hermetically sealed enclosures for the electronics
  • High pressure blowers to keep the lenses clean

EM919 Building Blocks:

Core Components (per stack):

Basic Unit EM919 Blower Unit BP919
  • Transmitter unit
  • Receiver & CPU unit
  • Blower Panel with distribution subassembly
  • Blower hoses


Common components (per plant):

Hand Held Unit HHT919
  • Tool for programming
  • Entering Calibration Data
  • Access the parameters
  • Used in absence of a DCS interface communication over MODBUS
  • Common for multiple Emission Monitors in a plant

Technical Specifications:


Specifications: Range / Values
Measuring Range Selectable range
0 to 500 mg/N cu.m
0 to 1000 mg/N cu.m
Max distance Between transmitter and receiver 15 m
Process Temperature Upto 250 C with standard insulation
Upto 450 C with thermal insulation and aluminium cladding around stack.
(Insulation not in IFI Scope)
Accuracy +/-  2% of Span
Resolution 1 mg/Nm3
Analog Outout 1 No. 4 to 20 mA non- isolated, 500Ω Max predefined as measured emission.
Digital Output 2 No. Relay outputs (Potential Free N/O Contacts),
Predefined as Emission high alarm and maintenance alarm.
Communication Ports

2 Nos. Serial Communication Ports

  1. RS 232 (2 Wire) local communication
  2. RS 485 (4 Wire) remote communication.
Communication Protocol MODBUS Serial (default). PROFIBUS connectivity can be provided if required.
Blower Specs 1400 mm WC (max), 144 m3/hr Max
Power Supply EM919 :  110 V / 220 V, 1 Phase, 50 Hz (to be specified at time of order)
BP 919 : 415 V AC, 3 Phase, 50 Hz.
Power Consumption EM 919 : 0.01 KVA
BP 919 : 1.5 kW
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