Liquid Analyzer for Turbidity and Chlorine FLXA402T

Providing reliable turbidity and chlorine measurements in Water Treatment Plants since 1959
No.1 Process analyzer supplier to Japanese market*

“Reduce initial cost with reliable products”

“Want to monitor status from remote place”

Many of our customers face these challenges - Yokogawa Turbidity and Chlorine Analyzers resolve them.

The FLXA402T offers multiple connection possibilities, eliminating the need for multiple analyzers and providing greater flexibility. This four-wire analyzer includes a color HMI and an easy touchscreen operation with a simple menu structure in 8 languages for simple and efficient setup and configuration.

With its modular design, the FLXA402T analyzer offers a range of measurement choices with the respective sensor module, including turbidity, chlorine, pH, Conductivity, and 4-20mA input. Dual sensor measurements save your install space and offer additional functionalities, such as pH compensation for the Chlorine analyzer.

*Based on a Yokogawa survey in 2019

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.


FLXA402T Features

Support up to 2 sensors

FLXA402T has a modular structure and can insert up to 2 sensor modules. You can choose the Turbidity module or Chlorine module as a 1st module, and Turbidity module, Chlorine module, pH module, or conductivity module is available as a 2nd module.

FLXA402T Module

Expert Guide: Clear Touch Panel Display for Improved Operability

The FLEXA series analyzer provides improved operability with intuitive touchscreen operation, featuring a clear display and user-friendly indication with eight languages*. Sensor status and estimated maintenance time notification improve efficiency. The interactive screen is housed in a robust aluminum die-cast housing. ​​​

easy to use touch screen

*8 languages: English, Chinese, Korean, German, French, Spanish, Portuguese, Japanese

Advanced Flexibility: Modular Design for Increased Scalability

The FLEXA™ series analyzer features a modular design with replaceable sensor modules, enabling the construction of various of systems. FLXA402T allows for the connection of up to two possible sensors resulting in a reduction in CAPEX and OPEX.


Preparing for the Future

Industrial automation is moving toward SMART products, with sensors changing from analog to digital SMART. This transition can affect plant operations and take time to implement fully.

In addition to being a high-performance standalone analyzer, the FLXA402T is also a component of the Yokogawa SENCOM4.0 Platform, SMART sensor systems give you more insight because they possess in-depth knowledge of their health status for predictive asset management and sensor condition to ease troubleshooting.

With the SENCOM4.0 Platform, upgrading to the next generation SMART product is easy and can be done at any time with little impact on operations.

Easy to get information and operate from remote place

Data Mobility

SD card or Ethernet for easy data transfer and remote service, allowing for more in-depth process analysis. 


  • Turbidity of tap water, sewage, river water and water used in general processes
  • The Chlorine Analyzers intended for measurements in the water distribution network, at pumping stations, water delivery points, schools, and public facilities.

Analyzer specialized for water applications

System Configuration

Turbidity and Chlorine 2 in 1 system configuration

The first module can be connected the Chlorine sensor unit or the Turbidity detector unit, and the second module can be connected the Chlorine sensor unit, Turbidity detector unit , pH sensor or conductivity sensor. For example, Chlorine sensor unit and Turbidity detector unit can be controled by one Liquid Analyzer.

System Configuration FLXA402T-FC800D-TB820D

Turbidity Measurement 

Easy to clean cell structure, Automatic wash system, Long life time light source

Right Angle Scattered Light Turbidity Detector TB820D

The TB820D is SENCOM4.0 family and can connect to FLXA402T. Thanks to smart unit equipped detector, TB820D gives you more insight in ordinary operation.

Learn more


Chlorine Measurement 

Minimize chlorine injection, remote maintenance and reduce maintenance time

Non-reagent Type Free Available Chlorine Sensor Unit FC800D

The FC800D is SENCOM4.0 family and can connect to FLXA402T. Thanks to smart unit equipped behind of electrode unit, FC800D gives you more insight in ordinary operation.

Learn more



pH and Conductivity Measurement

You can find the best pH and Conductivity solution for your process

YOKOGAWA’s pH and Conductivity sensors are highly reliable and very unique. You can select the most valuable sensor.

pH and conductivity sensors



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