Measure CO with confidence

Whether for process control or quality control, gas suppliers need accurate, low-level contaminant monitoring to ensure gas quality with no impurities. For refineries and chemical plants it is especially critical to measure carbon monoxide in hydrogen since high levels can poison a customer’s process and a supplier’s reputation.

Monitor purity with the HALO 3 CO analyzer, designed to provide unparalleled accuracy and reliability for your most critical carbon monoxide measurements. Compact and easy to use, this analyzer features Tiger Optics’ proven Cavity Ring-Down Spectroscopy to detect less than 100 ppb of carbon monoxide in your process streams.

Users enjoy freedom from periodic sensor maintenance, and with no calibration gases required, operating costs are nearly eliminated. With drift-free stability and rapid response time, the HALO 3 CO is ideal for the continuous, online gas monitoring that is critical to process control in gas and chemical industries or anywhere purity is a necessity.

The HALO 3 CO ensures purity and process protection with:

  • Parts per billion (ppb) carbon monoxide detection capability
  • Wide measurement range, from 0 – 2000 parts per million (ppm)
  • Freedom from calibration (absolute measurement technology)
  • Low cost of ownership
  • Compact design
  • Simple software interface


  • CEM Standards Preparation
  • Gas Quality Control
  • Gaseous CRMs & Calibration Gas Mixtures
  • High-Purity Gases & Systems
  • Hydrogen Fuel Cells
  • Research & Development
  • Syngas & Fuel Gas Production



Laboratory & Scientific

Stack, Process & CEMS

Detection Capability

Detection and Matrix Range LDL (3σ) Precision (1σ) @ zero
CO in N2 0 – 2000 ppm 75 ppb 25 ppb
CO in H2 0 – 2500 ppm 100 ppb 35 ppb
CO in He 0 – 2000 ppm 75 ppb 25 ppb


Operating range See Detection Capability table
Detection limit (LDL, 3σ/24h) See Detection Capability table
Precision (1σ, greater of) ± 0.75% or 1/3 of LDL
Accuracy (greater of) ± 4% or LDL
Speed of response < 1 minute to 90%
Environmental conditions 10°C to 40°C, 30% to 80% RH (non-condensing)
Storage temperature -10°C to 50°C
Gas Handling System and Conditions
Wetted materials 316L stainless steel (optional corrosion-resistant material), 10 Ra surface finish
Leak tested to 1 x 10-9 mbar l / sec
Inlet pressure 10 − 125 psig (1.7 − 9.6 bara)
Flow rate Up to 1.8 slpm
Sample gases Most inert, toxic, passive and corrosive matrices
Gas temperature Up to 60°C
Dimensions, H x W x D
Standard sensor 8.73″ x 8.57″ x 23.6″ (222 mm x 218 mm x 599 mm)
Sensor rack (fits up to two sensors) 8.73″ x 19.0″ x 23.6″ (222 mm x 483 mm x 599 mm)
Standard sensor 28 lbs (12.7 kg)
Alarm indicators 2 user programmable, 1 system fault, Form C relays
Power requirements 90 − 240 VAC, 50/60 Hz
Power consumption 40 Watts max.
Signal output Isolated 4−20 mA per sensor
User interfaces 5.7” LCD touchscreen, 10/100 Base-T Ethernet, RS-232
802.11g Wireless (optional), Modbus TCP (optional)
Certification CE Mark
U.S. Patent #7,277,177

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