Color Analyzer

Color Analyzer

Benefiting from the stability of full-spectrum analysis, the OMA Color Analyzer provides extremely reliable sample color analysis; this system is an ideal colorimeter for hydrocarbon fuel streams (e.g. diesel, naphtha).

The color of liquid in a process stream is often observed as an indicator of potential problems with product quality or equipment. Subtle changes in process coloring can signify a variety of issues, including dips in process efficiency, overheating, floating dilution ratios, distillation column malfunction, and equipment failure (e.g. leaky heat exchangers or filter breakdown).

Human judgment on color is subjective and variable. The common photometric detector is dependent on a single, isolated measurement wavelength — a method susceptible to distortion from bubbling, contamination, or wavering light levels, as all of these conditions are misrepresented in readings as color changes.

The OMA system continuously measures sample color using full-spectrum visible absorbance spectrophotometry. The photodiode array measures absorbance at every single integer wavelength in the visible range from 340 to 720 nm; the ECLIPSE software uses this rich collateral data to secure the measurement against the typical distorting phenomena.

  • Continuous measures sample color using dispersive UV-Vis absorbance spectroscopy
  • Totally solid state build with no moving parts — modern design for low maintenance
  • Ideal instrument for color analysis of: hydrocarbon liquid streams (diesel, gasoline, LNG, kerosene, natural gas liquids, naphtha, heavy distillate), wastewater, and food & beverage product streams
  • Easily configurable software can use any standard color scale or a custom (nonstandard) correlation
  • Ultra-safe fiber optic design with dedicated sample flow cell — no toxic/corrosive sample fluid in analyzer enclosure
  • No re-calibration required after initial system setup — Auto Zero normalizes spectrophotometer reading
  • Stable xenon light source with average 5 year lifetime

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Applications: OMA Color Analyzer

Available Color Scales

Proven Applications

Color Absorbance Spectrum

Example: the APHA color of a sample (e.g. wastewater) corresponds directly to the height of the sample's absorbance curve in the 425-445nm wavelength region. The OMA monitors this region to determine the real-time sample color in the APHA scale. The system is calibrated using the absorbance of distilled water to represent APHA 0 and a 500 ppm PtCo stock solution to represent APHA 500.

Absorbance Curve: APHA Scale

Absorbance (AU)
Wavelength (nm)


All OMA models are equivalent in function and performance with identical electronic configurations. The models vary by form factor and materials of construction, each intended for a unique use case.



Wall-mounted process analyzer

  • Indoor/outdoor use
  • ATEX, Class I Div 1/2, GOST...
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Suitcase process analyzer

  • Carry from site to site
  • Rugged suitcase enclosure
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Rackmount process analyzer

  • Fits standard 19" rack
  • Ideal for lab/shelter
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Explosion-Proof Models

The OMA-300 is offered in two explosion-proof formats:

Exp (Purged) Explosion-Proof OMA-300


Eexp systems are purged and pressurized using a certified air-purging device. This method ensures that toxic/explosive gas is not allowed to accumulate inside the enclosure and is ideal when instrument air is available.

Exd (Cast Aluminum) Explosion-Proof OMA-300


Eexd systems are contained within certified explosion-proof cast-aluminum enclosures. This method is more practical if the installation is remote or utilities are unreliable.


The OMA is built for direct analysis of the hot/wet sample, thus simplifying the scope of the sample system and retaining high sample integrity. From our vast experience in sampling design, we know that applications can be similar but are rarely identical. For this reason, we design and build sample conditioning systems on a project basis, working from the process to the drawing board.

Specifications: OMA Color Analyzer

Note: All performance specifications are subject to the assumption that the sample conditioning system and unit installation are approved by Applied Analytics. For any other arrangement, please inquire directly with Sales.

Measurement PrincipleDispersive Vis/NIR absorbance spectrophotometry
Detectornova II™ Vis/NIR diode array spectrophotometer
Spectral Range200-800 nm
Light SourceTungsten lamp (average 2 year lifespan)
Signal Transmission600 μm core 1.8 meter fiber optic cables
Other lengths available
Path LengthApplication-dependent
Sample ConditioningCustom design per application
Analyzer CalibrationIf possible, analyzer is factory calibrated with certified calibration fluids; no re-calibration required after initial calibration; measurement normalized by Auto Zero
Reading VerificationSimple verification with samples and self-check diagnostic
Human Machine InterfaceIndustrial controller with touch-screen LCD display running ECLIPSE™ Software
Data StorageSolid State Drive
Analyzer EnvironmentIndoor/Outdoor (no shelter required)
Ambient TemperatureStandard: 0 to 35 °C (32 to 95 °F)
Optional: -20 to 55 °C (-4 to 131 °F)
To avoid radiational heating, use of a sunshade is recommended for systems installed in direct sunlight.
Sample TemperatureStandard: -20 to 70 °C (-4 to 158 °F)
Optional: up to 150 °C (302 °F) with cooling extensions
Contact AAI for temperatures above 150 °C (302°F)
Sample PressureUsing standard flow cell: 206 bar (3000 psi)
Using immersion probe: 100 bar (1470 psig)
Electrical85 to 264 VAC 47 to 63 Hz
Power Consumption45 watts
Standard Outputs1x galvanically isolated 4-20mA analog output per measured analyte(up to 3; additional available by upgrade)
2x digital outputs for fault and SCS control
Optional OutputsModbus TCP/IP; RS-232; RS-485; Fieldbus; Profibus; HART;
Select analyzer type:OMA-300 Wall-Mounted Analyzer
OMA-206P Portable Analyzer
OMA-406R Rackmount Analyzer
Response Time1-5 seconds
Repeatability±0.5% of scale
Noise±0.004 AU at 220 nm
Standard Design General Purpose
Available Options ATEX, IECEx, EAC, PESO, JPN
Please inquire with your sales representative for additional certifications (CSA, FM etc.).

Resources: OMA Color Analyzer

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