Zirconia Oxygen/Humidity Analyzer ZR22G, ZR802G

Contribute to OPEX reduction

Contributes to OPEX reduction, and continuously measures oxygen concentration and humidity under high temperature without the need for a sampling device.

This analyzer consists basically of a probe and a converter that are used as both a Zirconia Oxygen Analyzer and High Temperature Humidity Analyzer.

The ZR802G converter uses a digital display, displays the cell temperature and cell emf in addition to the oxygen concentration and includes a Human Machine Interface (HMI), that offers easy touch screen operation. This analyzer is most suitable for monitoring the oxygen concentration of combustion gases in large or small boilers, various industrial furnace and combustion devices, or for the control of low-oxygen combustion.

Separate type Zirconia High Temperature Humidity Analyzers are used to measure the humidity of hot gases continuously in driers which use an electrical heater or hot gas as the heat source. They can also be used in a variety of manufacturing applications in humidifiers, as well as in driers, for humidity measurement and control. They can help improve productivity in these application fields.

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About OpreX

OpreX is the comprehensive brand for Yokogawa’s industrial automation (IA) and control business and stands for excellence in the related technology and solutions. It consists of categories and families under each category. This product belongs to the OpreX Analyzers family that is aligned under the OpreX Measurement category.  


Features & Benefits


  • The built-in heater assembly of the probe can be replaced on site, reducing maintenance costs.
  • The probe uses a long-life, high-reliability Zirconia sensor.
  • The probe uses three-reference gas supply methods (natural air convection, instrument air, and pressure compensated) in its applications.
  • The converter incorporates the LCD touchscreen for ease of operation.


  • This converter can be used as an oxygen analyzer as well as a high temperature humidity analyzer.
  • The deterioration status of the sensor can be confirmed by the sensor resistance check function (self-diagnosis function) in the converter. New
  • The converter records history of alarm on/off, measured value history for up to 40 days, and others. New
  • The integrated type integrates both probe and converter, to reduce wiring, piping, and installation costs. This type of unit uses an optical switch for ease of operation at the site.
  • Remote maintenance using digital communications (HART, Modbus TCP and RTU) reduces maintenance costs.



Zirconia Oxygen Analyzer

  • Large or small/medium-sized boilers (for electric power, heavy oil, gas and coal, etc.)
  • Various industrial furnaces (oil / steel heating furnaces, coal kilns, etc.)

Zirconia Humidity at high temperatures  Analyzer

  • Coloring process of textile factory
  • Steam curing process for concrete products
  • Various manufacturing and drying processes for building materials, wood, food, etc.
  • Various manufacturing and humidification processes for food products, etc.

Please contact us for other applications.


Creating new value with industrial IOT (IIOT)

Manage even a large-scale plant, the subdivided plant with the minimum staff.

Creating new value with industrial IOT (IIOT)

General Purpose Specifications

Measurement Object Oxygen analyzer: Oxygen concentration in combustion exhaust gas and mixed gas
Humidity Analyzer: Water vapor (in vol%) in mixed gases (air and water vapor)
Measurement System Zirconia System (Detector ZR22G)
Measurement Range O2: 0.01–100 vol%
H2O: 0–100 vol%
Mixture ratio: 0–1.000 kg/kg
Digital Communication HART7 (AO1, 250 to 550 Ω)
Ethernet (Modbus TCP)
RS-485 (Modbus RTU)



Repeatability O2: ± 0.5% F.S. (0 to 5 vol% O2 or more and less than 0 to 25 vol% O2 range)
O2: ± 1% F.S. (0 to 25 vol% O2 or more and up to 0 to 100 vol% O2 range)
H2O: ± 1 vol%H2O (Sample gas pressure 2 kPa or less)
Linearity O2: ± 1% F.S. (0 to 5 vol% O2 or more and less than 0 to 25 vol% O2 range)
O2: ± 3% F.S. (0 to 25 vol% O2 or more and less than 0 to 50 vol% O2 range)
O2: ± 5% F.S. (0 to 50 vol% O2 or more and up to 0 to 100 vol% O2 range)
H2O: ± 2 vol%H2O (sample gas pressure: within ± 0.49 kPa)
H2O: ± 3 vol%H2O (sample gas pressure: 2 kPa or less)
Drift O2: Both zero and span ± 2% F.S. /month
H2O: Both zero and span ± 3 vol%H2O /month
Response Time Response of 90% within 5 seconds.


Basic System Configuration

Basic System Configuration



To detect air leaks, an oxygen analyzer is used. The ZR22/ZR802 Direct In-Situ Zirconia Oxygen Analyzer has been well received due to its good response speed, stability, and maintainability.


Drying is an important part of the papermaking process that evaporates the remaining water in the wet paper web. This is performed with a dryer, and the humidity control in this dryer is essential to maintaining high paper quality (e.g., strength, paper surface) and high heat energy efficiency.


There are various methods for continuous fabric dyeing as well as dye fixing. When dye is directly applied, steaming (heat treatment) is required. At present the pad-steam method is widely used for continuous dyeing. To ensure stable product quality, the humidity in the steamer is kept at a constant level. 


Humidity control is important to maintain product quality and improve yield. The ZR402G/HS Direct In Situ Zirconia High Temperature Humidity Analyzer is easy to maintain as it requires no sampling system.


A furnace for heating slabs needs to be operated under low oxygen conditions at high temperatures of 1000°C and above to prevent oxidation of the steel. The measurement of oxygen concentrations in the furnace is essential in this process. (AN 10M01F01-03E)


In a pulverized coal-fired boiler of a large power plant, an oxygen analyzer is essential for combustion control. A pulverized coal-fired boiler is an industrial or utility boiler that generates thermal energy by burning pulverized coal (also known as powdered coal or coal dust).


In a hot blast stove, the by-product gas produced in a coke oven is burned to preheat the air blast for the blast furnace. To improve the combustion efficiency and conserve energy in a hot blast stove, it is essential to be able to control combustion by measuring and adjusting the oxygen concentration in the exhaust gases.


A package boiler operates more efficiently if the oxygen concentration in the flue gas is reduced. Optimizing air intake for boiler operation requires continuous measurement of the oxygen concentration in the flue gas.