Explosion proof Zirconia Oxygen Analyzer, Converter ZR802S, ZR22S

Contributes to OPEX reduction, safe operation and maintenance work

This oxygen analyzer consists of a ZR22S zirconia probe and a ZR802S converter and expands the line-up of explosion-proof products for oxygen analyzers.

The ZR802S converter is the only product in the zirconia oxygen analyzer market that supports all three of the following communication protocols: HART7 for analog output, Modbus TCP and Modbus RTU for digital communications. It also complies with the NAMUR NE43 guideline governing the behaviour of signals to indicate a sensor fault and the NAMUR NE107 guideline for on-site instrument self-assessment functions.

The self-assessment function of the ZR802S converter can regularly measure the resistance value of the sensor in the ZR22S probe and send this data to the plant’s control system. Sensor resistance is a strong indicator of sensor deterioration, and this can then be used to remotely diagnose deterioration of the sensor to allow corrective action before the condition progresses.

Early sensor condition detection will enable more efficient maintenance scheduling, thereby maintaining the plant operating rate and reducing costs.

The ZR802S converter uses a digital display, which shows the cell temperature, EMF and oxygen concentration. The Human Machine Interface (HMI) offers easy operation via an intuitive touch screen. This analyzer is most suitable for monitoring combustion and controlling the low-oxygen combustion of various industrial furnaces in explosive atmospheres at petroleum refineries, petrochemical plants, and natural gas plants.


Features & Benefits

  • Long-life & high-reliability zirconia sensor
    The probe uses a long-life, high-reliability Zirconia sensor that has a proven track record of long life and minimized sensor deterioration.
  • Intuitive Operation
    The converter incorporates the LCD touchscreen for ease of operation, allowing many functions to be operated without opening the cover.
  • Deterioration diagnosis
    The deterioration status of the sensor can be confirmed by the sensor resistance check function (self-diagnosis function) in the converter.
  • Reducing maintenance costs
    The built-in heater assembly of the probe can be replaced on-site, reducing maintenance costs.
  • Multiple communication options
    Remote maintenance using digital communications analog output (HART7) and digital communication (Modbus TCP/RTU) reduce maintenance costs by providing location-free management.
  • Complete history up to 40 days
    The converter records the alarm history on/off, measured value history, and others for up to 40 days.
    Easy to check and retrieve logs: You can display the logs directly on the site screen or use the SD card to acquire the data and display it in other places. In the event of an error, it is possible to determine whether it is caused by the analyzer or by the DCS, thus reducing maintenance man-hours and downtime for resolution.


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.  


Excellent operability converter

Operation without opening the cover

  • It can be operated in the field without opening the cover using an infrared switch.

Touch panel operation when the cover is open

  • Interactive and easy operation (e.g. settings, trends, calibration operation).
  • It can be easily operated in six languages: English, French, German, Chinese, Portuguese, and Japanese.
  • The most appropriate action to be taken when an error/alarm occurs is also displayed, augmenting the knowledge and experience of the service person.
Operation without opening the cover


Interactive and easy operationscreen


Creating new value with industrial IOT (IIOT)

Manage a large-scale plant or subdivided plant.
Expansion of Communication Standards.

Hart5 only


"Modbus communication.
I can't connect it to the device."

"Wiring is difficult with analog signals..."



Communication Standard
Modbus TCP/Ethernet
Modbus RS 485



Operator Benefits

Advantages unique to ZR802S

  • Abnormality detection
    Accessible logs for easy detection of abnormalities reduce the costs of problem-solving.
  • Reliable detector
    Robust Zirconia Sensor with Long Life and Stable Operation.
  • Long-life
    High durability and corrosion resistance due to a special coating that protects from deterioration
  • Durable in dusty conditions
    A special coating protects from dust, removing the need for a dust filter, thereby reducing downtime caused by regular filter replacement.



  • Combustion management for heating furnaces and decomposition furnaces in the fields of oil refining, petrochemicals, and chemicals
  • Combustion management for various types of furnaces, such as those used in steel production and waste incineration
  • Combustion control for boilers at power plants

Oil refining process, O2 measurement points
Oil refining process、O2 measurement points

Heating furnace for decomposing
in a petrochemical process

Hearting furnace for decomposing in a petrochemical process


Basic System Configuration

Separate type Explosion-proof

*Both sensor and transmitter are explosion-proof.


Basic System Configuration


Measurement Object Oxygen concentration in combustion exhaust gas and mixed gases (excluding inflammable gases)
Oxygen Concentration 0.01 to 21 vol% O2
Measurement Range O2: 0.01–100 vol% (In the case of explosion-proof use, oxygen concentration shall not exceed 21 vol% O2)
Sample gas temperature 0 to 700℃
700 to 1400℃ (with High Temperature Probe Adapter)
Sample gas pressure -5 to +5 kPa (For 0.15 probe, -0.5 to +5 kPa)
Insertion length -5 to +5 kPa (For 0.15 probe, -0.5 to +5 kPa)
Ambient Temperature ZR22S: -20 to +60℃
ZR802S: -20 to +55℃
Power Supply Voltage 100 to 240 VAC 50/60 Hz
Hazardous location approvals ATEX, IECEx, FM, CSA, China Ex, Korea Ex, India Ex, Taiwan Ex



Repeatability O2: ± 0.5% FS (0 to 5 vol% O2 or more and less than 0 to 25 vol% O2 range)
O2: ± 1% FS (0 to 25 vol% O2 or more and up to 0 to 100 vol% O2 range)
Linearity O2: ± 1% FS (0 to 5 vol% O2 or more and less than 0 to 25 vol% O2 range)
O2: ± 3% FS (0 to 25 vol% O2 or more and less than 0 to 50 vol% O2 range)
O2: ± 5% FS (0 to 50 vol% O2 or more and up to 0 to 100 vol% O2 range)
Drift O2: Both zero and span ± 2% FS/month
Response Time Response of 90% within 5 seconds.




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