All-in-One Digital SMART pH/ORP Sensor FU24F
Notice: This product was discontinued on Jun 1, 2022.

The FU24F is a an all-in-one digital smart pH and ORP sensor made with a chemical resistant PPS 40GF body for harsh pH applications.  It is particularly useful in harsh applications with fluctuating pressure and/or temperature. These processes shorten sensor life because the process fluids move in and out of the sensor under influence of frequent pressure and/or temperature fluctuations. This results in fast desalting and dilution of the reference electrolyte which in turn changes the reference voltage causing a drifting pH measurement.

By integrating the successful Yokogawa patented Bellow design concept within the FU24F electrode, a strong pressure compensation mechanism is created. The built-in bellow ensures immediate interior pressure equalization to the outside pressure, making the sensor virtually insensitive to external pressure variations. A slight overpressure caused by the bellow tension, prevents fluid ingress and maintains a positive ion flow out of the sensor.


  • Solid Platinum ORP/LE electrode for accurate simultaneous pH and ORP measurements
  • Integral Pt1000 element for enhanced pH accuracy
  • Extended life time by saturated Ag/AgCl reference system with double junction combined with ion-trap, and porous PTFE reference diaphragm
  • Easy setup by sensor specific characteristics stored in the sensor itself
  • Simple maintenance by comprehensive design
  • Available in two versions, a robust dome shape model for applications with a limited amount of solids, and a flat surface model for applications in which solids are a considerable component
  • IP67 M9 Cable Connection
  • CE, ATEX, CSA and FM Approval. However *Can only be used General Purpose at this time, because FLXA21 SENCOM™ module and SPS24 Interface box are pending ICECx, ATEX, FM and CSA approval*


SPS24 PC Configuration and Calibration Software



Ultrapure water, UPW, high-purity water and deionized (DI) are all terms describing basically the same property. They refer to water which has been purified to the highest standards by removing all contaminants such as, organic and inorganic compounds; dissolved and particulate matter; volatile and non-volatile, reactive and inert; hydrophilic and hydrophobic; and dissolved gases. The purified water has very low conductivity which means it is high in resistance because all the conductive components have been removed. In low conductive solutions combined with its susceptibility to contamination and temperature effects makes accurate pH measurement very difficult.

Most pH sensors with a glass membrane cannot be mounted upside down. To absorb the thermal expansion of the internal buffer solution there is always a sizeable air bubble inside the sensor. When the sensor is mounted upside down the reference element...
Yes, the SENCOM Module in these sensors allows a Modbus Master to connect using Modbus RTU protocol and access the following data: pH Temperature compensated pH ORP pH compensated ORP rH Temperature Junction resistance value Sensor details ...
Yes, the input module can be changed in the Converter.    See the FAQ: Which Input Module do I order for my FLXA21/202 analyzer? ...




Are Pure water, Ultrapure water, UPW, or Water for Injection (WFI) important in your process? Would a better understanding of current water treatment equipment technology be useful? Would learning to better identify sources for potential process problem be helpful?

Pure water, Ultrapure water, UPW, Water for Injection (WFI), high-purity water and deionized (DI) are all terms describing basically the same property. They refer to water which has been purified to the highest standards by removing all contaminants such as, organic and inorganic compounds; dissolved and particulate matter; volatile and non-volatile, reactive and inert; hydrophilic and hydrophobic; and dissolved gases. Pure water or conditioned water is used in a variety of processes across various industries; Power Generation, Pharma/Biotech, Semiconductor, and Drinking water are just a few examples. Please join us for a free 45 min webinar with 15 min Q&A section. As our presenter David H. Paul, Inc (DHP), gives an overview of high purity water treatment. What you will learn:

  • Understanding the purpose for each piece of equipment in a high purity treatment process flow
  • Basic overview of Reverse Osmosis Processes
  • Better understanding of when to "raise an alarm" when performance issues arise

Information about the presenter: Since 1988, David H. Paul, Inc (DHP) has been the world's leader in reverse osmosis and high purity water treatment training. DHP has trained over 18,000 water treatment professionals worldwide. For information on additional High Purity Water Treatment and Reverse Osmosis Water Treatment training please click on the link to DHP's website:


Proper pretreatment is critical for minimizing problems and reducing the need for chemical cleaning. This webinar will teach you the most common pretreatment technologies and why it is important to monitor and maintain them. Join us to learn:

  • Why pretreatment is important
  • How pretreatment protects your RO units from scaling, fouling and chemical attacks
  • What to monitor and why

Basic pH/ORP Theory and gain an understanding of:

  • How pH and ORP measurement works
  • The differences in measuring electrodes and reference electrodes
  • The difference between ORP and pH compensated ORP

How to choose the right reference and measuring electrode for your application, which includes:

  • The differences and benefits between all-in-one vs. individual electrodes
  • The benefits of SMART sensors
  • The difference between traditional and differential pH maintenance
  • Best practices for cleaning and calibrating
  • The benefits of sensor diagnostics and how to interpret the information

Each of the previous webinars covered the basics and the monitoring requirements for a high purity water treatment system that included a Reverse Osmosis (RO) treatment step. In this final webinar, we cover the problems that poor RO unit performance can produce in downstream process steps and in the end use water. The webinar series started with topics concerning raw water contaminants and will end with following contaminants through the RO membrane and into downstream treatment steps including Electrodeionization (EDI), mixed-bed ion exchange, 185 nm and 254 nm UV, ozone and more. Join us and learn:

  • What and why certain measurement parameters should be monitored
  • When to "raise the alarm" when issues arise

A common use for RO is for purifying water, removing salts and other impurities to improve the color, taste and other properties. It is regularly used for commercial and residential water filtration and is also one of the methods used for desalinization of seawater. RO systems are capable of rejecting bacteria, salts, sugars, proteins, particles, dyes, and other constituents which have a molecular weight of greater than 150-250 Daltons. RO systems are designed for automatic operation and require routine preventative and corrective maintenance. Common problems include membrane fouling and the use of improper flow rates. The result is reduced throughput capacity and shortened runs. What you will learn:

  • Overview of Reverse Osmosis Processes
  • Understanding of RO technology
  • Understanding the importance of RO operation and maintenance


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