Wide Body Sensor for Water and Wastewater PH21

At Yokogawa, we are committed to our responsibility of protecting the environment, and this sensor is the first step to achieving a zero emission future. The PH21 is the first pH sensor made from recycled PPS-GF40 materials without compromising the sensor body integrity. The PH21 was designed with the drinking water market in mind, where simplicity results in accuracy and reliable pH measurement, making this sensor an excellent choice in 80% of water-based applications.

Features and Benefits

  • Available as analog and digital SMART sensors (SENCOM)
  • Integral Pt1000 element for accurate temperature measurements and enhanced pH accuracy
  • Quick disconnect Variopin connector 
  • Simple maintenance by comprehensive design
  • Versatile Direct in-line, immersion, off-line installation (flow fitting) and retractable Hot-tap 
  • Quick-Release adapter available
  • Calibration certificate delivered with each sensor


Conventional SMART sensors come with integrated electronics on top of an analog sensor. Once the sensor reaches the end of its lifetime, the still functioning electronics must also be thrown away, adding to global waste. The SENCOM 4.0 platform consists of a reusable SMART adapter, requiring only the analog sensor to be disposed of when it reaches the end of its lifetime. With the SENCOM 4.0 platform, Yokogawa delivers reduced costs and waste while contributing to its long-term business goals of a sustainable future for all.

SA11Digital SMART SENCOM™ Adapter, SA11

The re-useable smart adapter, SA11, offers full measuring parameter functionality of analog sensors equipped with a Variopin connector and Yokogawa ID chip. The SA11 automatically recognizes the installed sensor and prepares the right configuration. 

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Optimizing four key factors will decrease pH sensor costs and optimize process control and overall plant efficiency.

The PH21 utilizes the reference pin inside the sensor to do the diagnostic measurements. It will still have most of the diagnostic information available.
The PH21 body is made of the same material as the FU20 and FU24: PPS-GF40, but a different color. This material is recycled material, but at present, there is no official certificate available for that.
The PH21 does not have a liquid Earth, hence does not measure ORP. When using a FU20 or FU24 ORP/REDOX will be measured, but will not show up in the display. Error messages can be configured for ORP and will give warnings. ...
This sensor is specifically designed to be used in water- and wastewater treatment applications. The specifications of the PH21 are lower than that of the FU20. For example, the PH21 can be used up to 60°C (140°F) and the FU20 105°C (221&...
Yes, it can be used as an analogue sensor connecting to the analogue module of the FLXA402.
No, it does not have an LE. For the type of market this sensor is developed for the LE is often not used. When necessary an earth can be connected on the mounting bracket of the SA11. Number 14 of the cable can be connected as normal. Provisi...
The WU11 cables are used between the BA11 and the FLXA402. WE10 is used between the FU20-VS / PH21-VS and FU24-VS and the SA11. ...


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