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Digital ammonium and nitrate sensor ISEmax CAS40D

Ion-selective Memosens sensor for the wastewater industry

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Digital ammonium and nitrate sensor ISEmax CAS40D

Ion-selective Memosens sensor for the wastewater industry

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Benefits

  • Nitrate and ammonium measured directly without the need for expensive sample conditioning
  • Optional potassium and/or chloride measurement compensates for cross sensitivities and ensures reliable measuring results
  • Low maintenance thanks to automatic flushing unit
  • Installed directly on the basin rim, no measuring container or sample-conveying pump required
  • Easy handling due to storage of sensor-specific data
FLEXible answers to individual needs
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Digital ammonium and nitrate sensor ISEmax CAS40D

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What is FLEX?

FLEX selections
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Fundamental selection Meet your basic measurement needs
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Lean selection Handle your core processes easily
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Extended selection Optimize your processes with innovative technologies
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Xpert selection Master your most challenging applications
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Manufacturer's warranty

Engineered for confidence

Our instruments are designed for long‑lasting performance, precise measurement, and dependable operation in demanding industrial environments. Each product includes a standard manufacturer’s warranty that reflects our commitment to quality and to the trust you place in our solutions.

Should a warranty case occur, the device will be assessed and the applicable remedy will be provided in line with the warranty terms – helping ensure a reliable and efficient resolution and supporting continued operation of your measurement point.

Request for extended warranty

If you require extended warranty coverage, simply contact your local Endress+Hauser representative. Our experts will advise you on the available options to match your application and risk profile, helping you protect your investment, reduce unexpected repair costs, and ensure reliable long‑term operation beyond the manufacturer's warranty period.

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Warranty terms apply

The manufacturer's warranty and extended warranty are subject to specific conditions. For full details, please refer to the locally applicable General Terms and Conditions (GTC), which can be found on the respective country page of our website.

Services by your side

Right‑first‑time commissioning, worldwide

Endress+Hauser’s qualified service engineers ensure your measurement devices are commissioned right the first time, delivering application‑aligned accuracy, regulatory compliance, and operational confidence from startup onwards, anywhere in the world.

Remote support you can trust wherever you operate

With Endress+Hauser Smart Support, you benefit from faster issue resolution, higher uptime, reliable global expertise across the entire product lifecycle – and lasting peace of mind.

Committed to long‑term, sustainable performance

With deep field expertise, harmonized processes, and continuous monitoring, we accompany you with comprehensive service offerings – from initial start‑up through instrumentation maintenance to process optimization – as a true lifetime partner delivering improved outcomes.

For additional information, please contact your local Endress+Hauser representative.

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Product information

ISEmax CAS40D - Sensor with Memosens technology using the ion-selective measuring principle
Digital ammonium and nitrate sensor
Specifications
Measuring / Application task Analyser
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Description

ISEmax CAS40D is the right technology for trend measurement directly in the basin. It helps you to increase the efficiency and reduce the energy costs of your aeration processes. The sensor works without reagents saving you even further money. With its robust ion-selective membranes and excellent self-cleaning, it eases your maintenance tasks. Thanks to Memosens, CAS40D combines maximum process and data integrity with best operating comfort and simplifies predictive maintenance.

Field of application

ISEmax CAS40D measures ammonium, nitrate and pH in municipal wastewater treatment plants:

  • Aeration basins - Determination of ammonium and nitrate concentration - Control and regulation of ammonium decomposition - Load-dependent aeration control for optimization of the treatment process
  • Inlet of aeration basins - Determination of ammonium load (pH-compensated)
Benefits
  • Nitrate and ammonium measured directly without the need for expensive sample conditioning
  • Optional potassium and/or chloride measurement compensates for cross sensitivities and ensures reliable measuring results
  • Low maintenance thanks to automatic flushing unit
  • Installed directly on the basin rim, no measuring container or sample-conveying pump required
  • Easy handling due to storage of sensor-specific data
Predecessors
ISEmax CAS40
Downloads
Most downloaded
Technical Information (TI)
ISEmax CAS40D Ion-selective sensor for continuous measurement of ammonium, nitrate and
other ions
English version - 12/2020
Download
Operating Instruction (BA)
ISEmax CAS40D Ion-selective sensor for continuous measurement of ammonium, nitrate and
other ions
English version - 12/2020
Download
Operating Instruction (BA)
ISEmax compressed air cleaning unit (230 V AC) Operating Instructions ISEmax compressed air cleaning unit (230 V AC)
English version - 11/2017
Download
The CAD Drawings will be available after the configuration.
All downloads
306 Downloads
Technical Information (TI)
Most downloaded
ISEmax CAS40D Ion-selective sensor for continuous measurement of ammonium, nitrate and
other ions
English version - 12/2020
Download
Operating Instruction (BA)
ISEmax compressed air cleaning unit (230 V AC) Operating Instructions ISEmax compressed air cleaning unit (230 V AC)
English version - 11/2017
Download
Operating Instruction (BA)
Most downloaded
ISEmax CAS40D Ion-selective sensor for continuous measurement of ammonium, nitrate and
other ions
English version - 12/2020
Download
Operating Instruction (BA)
Operating Instructions - Compressed air cleaning unit - 115VAC Operating Instructions - Compressed air cleaning unit - 115VAC
English version - 01/2013
Download
Installation Instructions (EA)
Kits CAS40D Sensor internal Kit instruction manual for several CAS40D spare parts
English version - 02/2025
Download
Fields of Activities (FA)
Sensors, transmitters, compact devices and assemblies Experts in Liquid Analysis
English version - 02/2026
Download
Fields of Activities (FA)
Esperti nell’analisi dei liquidi Dai sensori singoli a soluzioni
complete “chiavi in mano”
Italian version - 01/2017
Download
Fields of Activities (FA)
Kompetenz in der Flüssigkeitsanalyse Vom Sensor bis zur schlüsselfertigen Komplettlösung
German version - 09/2022
Download
Fields of Activities (FA)
水質分析の専門知識 センサからすべてを備えた
ターンキーソリューションまで
Japanese version - 06/2025
Download
Fields of Activities (FA)
Analizzatori, sensori in loco e campionatori Esperti nell'analisi dei liquidi
Italian version - 11/2018
Download
Fields of Activities (FA)
Catálogo Portfolio Analítica Desde sensores hasta soluciones completas
Spanish version - 01/2017
Download
Fields of Activities (FA)
Sıvı analizinde uzmanlık Sensörlerden komple anahtar teslim çözümlere
Turkish version - 11/2023
Download
Fields of Activities (FA)
Analizzatori, sensori in loco e campionatori Esperti nell'analisi dei liquidi
Italian version - 03/2017
Download
Fields of Activities (FA)
アナライザ、現場センサおよびサンプラ 水質分析のエキスパート
Japanese version - 08/2025
Download
Fields of Activities (FA)
Catálogo Analizadores Analizadores, sensores y tomamuestras in situ
Spanish version - 11/2018
Download
Fields of Activities (FA)
Analyseurs, capteurs in situ et préleveurs Experts en analyses physico-chimiques
French version - 12/2023
Download
Fields of Activities (FA)
Expertise in liquid analysis From sensors to complete turnkey solutions
English version - 09/2022
Download
Fields of Activities (FA)
Analyzers, in-situ sensors and samplers Experts in Liquid Analysis
English version - 01/2023
Download
Fields of Activities (FA)
Jistota v analýze kapalin Od senzorů po kompletní dodávku na klíč
Czech version - 01/2017
Download
Fields of Activities (FA)
Sensoren, Messumformer, Kompaktgeräte and Armaturen Kompetenz in der Flüssigkeitsanalyse
German version - 02/2026
Download
Fields of Activities (FA)
Sensori, trasmettitori, dispositivi compatti e armature Sensori, trasmettitori,
dispositivi compatti e armature
Esperti in materia di analisi dei
liquidi
Italian version - 06/2026
Download
Fields of Activities (FA)
Endress+Hauser 水質分析計ファミリ ラインナップと事例
Japanese version - 03/2017
Download
Fields of Activities (FA)
Analysatoren, In-Situ-Sensoren und Probenehmer Kompetenz in Flüssigkeitsanalyse
German version - 01/2023
Download
Competence Brochure (CP)
Making sure your WWTP runs and runs and runs Efficient and effective wastewater treatment
English version - 08/2018
Download

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Spare parts and accessories

further parts
further parts

Kit CAS40D Electrode protection cage

further parts
further parts
Order code 71130354
further parts
further parts

KitCAS40D Electrode holder, complete

further parts
further parts
Order code 71130357
further parts
further parts

Kit CAS40D Shared cables for electrodes

further parts
further parts
Order code 71130358
further parts
further parts

Kit CAS40D air jet for electrodes

further parts
further parts
Order code 71130359
Spare parts and accessories
ISEmax CAS40D - Sensor with Memosens technology using the ion-selective measuring principle
Digital ammonium and nitrate sensor

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Spare parts and accessories

further parts
further parts

Kit CAS40D Electrode protection cage

further parts
further parts
Order code 71130354
further parts
further parts

KitCAS40D Electrode holder, complete

further parts
further parts
Order code 71130357
further parts
further parts

Kit CAS40D Shared cables for electrodes

further parts
further parts
Order code 71130358
further parts
further parts

Kit CAS40D air jet for electrodes

further parts
further parts
Order code 71130359
Spare parts and accessories

Selection of compatible products

/