CEL-022 MkIII Density Measurement / Single Pass Opacity Monitor, Measures 0 - 100% Opacity

  • In situ measurement directly in exhaust gas flow using the widely accepted light transmission technique 
  • Measurement reading as % Opacity
  • Free utility software for PC based setup, control, and data logging
  • Rugged 316 stainless steel construction
  • Choice of interface options enabling easy integration
  • Optional Operator Interface with different mounting Configurations
  • Modulated green LED source for long lifetime stability and immunity to ambient light
Parameter (units)  Min / Max
Measurement Performance
Path Length, Flange to Flange (Mtr) 0.5 / 20 Flange-to-flange separation
Measuring Range (%) 0.0 / 100.0 User selectable
Accuracy (%) -2 / +2
Resolution (%) 0.1  Display resolution
Damping (s) 1 / 60  Selectable
Drift with Temperature (%) -2 / +2  Over any 20°C in the operating range
Operating Wavelength (nm) 510 / 540  Green LED
Power & Air Requirements 
Voltage (Vdc)  +24 Optional 90-260Vac PSU available  
Voltage Tolerance (%) -10 / +10   
Nominal Current Consumption (mA)  400   
Power Up Current Consumption (mA)  400   
Air Supply Volume Flow (L/min)  50 / 200  To each air-purge body 
Air Supply Fitting    1" BSP threaded aperture in each body 
Cable & Wire
Cable type - TX/RX Interconnection (cores) Screened multi-core, such as Belden 9873 
Cable type - OI/RX Interconnection (cores) Screened multi-core, such as Belden 9873  
Wire Size at Terminal Connections (AWG)  20 / 14   
Interface Options
Serial Comms  

ModBus via RS485 (OI or TRX)

Internal USB (OI), External USD (RX) 

Analogue Output, one (mA) 4 / 20  Isolated and scalable 
Digital Relay Contacts,two (A)  0 / 3  @ 30Vdc (signal level and data valid) 
Ingress Protection:   - TX/RX Heads IP65  For external use 

Ingress Protection:   - OI Wall Mounted

                             - OI Panel Mounted  



Hinged door & terminal compartment shut

From front face of panel when installed 

Ambient Operating Temperature (°C) -20 / +55  Air temperature around the heads 
Operating Humidity (%)  100  Air humidity around the heads  
Gas Temperature (°C)  +600 

Heat insulating gaskets included (higher

temperatures  on request)

Regulatory Compliance    

89/336/EEC (Electromagnetic Radiation)

72/23/EEC (Low Voltage) 

Materials:   - TX/RX Heads  316 Stainless Steel (powder coated) 
Materials:   - Air-Purge Bodies  Powder coated cast aluminium or stainless steel 

Materials:   - OI Wall Mounted

                 - OI Panel Mounted  


UL rated polycarbonate enclosure

Powder coated steel back-box

CW: Aluminium front panel with PU laminate & nylon 

Weight (kg) 2.5  TX  RX head plus aluminium air-purge body 

Weight (kg):   - OI Wall Mounted

                     - OI Panel Mounted  



Warranty (months) 24  Return to base warranty
Configuration Options: 

Configured with an OI                         (Wall / Panel Mounting):

Stand Alone Configuration:                  

Product Description:

The CEL-022 is an optical instrument designed to measure the visible opacity (0-100%) of exhaust gas in a duct, stack, or flue; typically the exhaust gas from an industrial combustion process or air filtration system.

The CEL-022 is available with or without an Operator Interface (control unit), so for the most cost effective monitoring solution the CEL-022 can operate as a “stand-alone” instrument consisting of the Transmitter head (TX) and Receiver head (RX), with all electrical connections (including outputs such as the alarm relays, 4-20mA and ModBus) being made inside the RX head. As a stand-alone instrument the CEL-022 is set-up and controlled using the supplied utility software, installed on a PC or laptop, and connected via the USB connector on the RX.

The CEL-022 has no moving parts, is of rugged design and has an excellent reliability record. Regular maintenance simply involves cleaning the TX and RX lenses, which are easily accessible due to our latched head design. Both the TX and RX heads are supplied with an air purge body, which when connected to a high volume source of clean air, keeps the contaminated stack gas away for the lens surfaces. An Aluminium air purge body is available for use on standard installations and a more advanced Stainless Steel air purge body is available for more demanding installations. 

The CEL-022 uses the standard single pass transmission measurement technique, with Transmitter/Receiver arrangement. A light beam emitted from the Transmitter passes across the stack to a Receiver, which measures the intensity of the received light. Increased particulate or smoke density in the stack gas attenuates the transmitted light and causes the intensity of the received light to fall. This reduction in intensity is measured and presented as % opacity.

The light source in the transmitter is a high intensity, high reliability green LED which provides long life and stable intensity. The transmitted light beam is pulsed to give complete immunity to ambient light levels. The intensity of the transmitted light is monitored at source so that any variations in the emitted light level are compensated for at the Receiver. The Receiver has on board temperature measurement to provide stability over temperature. 

When supplied with an Operator Interface (OI) all power supply and output connections are made in the OI rather than the RX. The OI is available in a range of enclosure styles, it has a bright 4 digit LED display and a simple 4 button keypad, which allows full command and control of the instrument. Alternatively, the free utility software can be connected to the OI and used to command and control the CEL-022 directly from a PC.  

Want more information, advice or prices? email us: info@conceptsmoke.com  

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CEL-022 MkIII - Data Sheet
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