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Digital pH sensor Memosens CPS91E

Memosens 2.0 pH electrode for heavily soiled media in chemical processes, paper or paint production

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Digital pH sensor Memosens CPS91E

Memosens 2.0 pH electrode for heavily soiled media in chemical processes, paper or paint production

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Benefits

  • Reliable measurement in heavily soiled media: Open aperture cannot be blocked by fibres or suspended solids.
  • Not affected by fluctuations in pressure and temperature: Thanks to open aperture no diffusion potential can build up at the junction.
  • Stabilized gel filling allows for low maintenance and a long sensor lifetime.
  • Memosens 2.0 offers extended storage of calibration and process data, enabling better trend identification and providing a future-proof basis for predictive maintenance and enhanced IIoT services.
  • Non-contact, inductive signal transmission eliminates disturbances caused by moisture or corrosion, ensuring highest process safety.
  • Lab calibration and quick sensor exchange in the process maximize process uptime and reduce operating costs.

Integrated technologies

Memosens technology
Liquiline: cutting-edge transmitter platform
FLEXible answers to individual needs
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Digital pH sensor Memosens CPS91E

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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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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.

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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.

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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.

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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.

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Technology
Memosens technology

Memosens 2.0: Cutting-edge sensor technology reloaded

Make life easier, increase process safety and stay connected with Memosens 2.0 digital technology.

Technology

Liquiline: cutting-edge transmitter platform

By choosing the Liquiline platform, you’re effectively choosing to spend less money on stock holding, save installation time and gain operational safety!

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Product information

Memosens CPS91E - Digital pH sensor for chemical processes, paper or paint production
Memosens CPS91E digital pH sensor
Specifications
Measuring / Application task pH
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Description

Memosens CPS91E is equipped with Memosens 2.0 digital technology, offering enhanced data storage for predictive maintenance and IIoT. The sensor features an open aperture that prevents fouling and ensures the most reliable measurement in fibrous media or media with a high content of suspended solids such as dispersions, precipitations or emulsions. Memosens CPS91E is completely resistant to moisture and can be pre-calibrated in the lab which facilitates operation and improves process integrity.

Field of application
  • Chemical processes
  • Pulp and paper industry
  • Contaminated media and suspended solids - Dispersions - Precipitations
- Emulsions

With ATEX, IECEx, CSA C/US, NEPSI, Japan, INMETRO approvals for use in hazardous areas, zones 0, 1 and 2.

Benefits
  • Reliable measurement in heavily soiled media: Open aperture cannot be blocked by fibres or suspended solids.
  • Not affected by fluctuations in pressure and temperature: Thanks to open aperture no diffusion potential can build up at the junction.
  • Stabilized gel filling allows for low maintenance and a long sensor lifetime.
  • Memosens 2.0 offers extended storage of calibration and process data, enabling better trend identification and providing a future-proof basis for predictive maintenance and enhanced IIoT services.
  • Non-contact, inductive signal transmission eliminates disturbances caused by moisture or corrosion, ensuring highest process safety.
  • Lab calibration and quick sensor exchange in the process maximize process uptime and reduce operating costs.
Predecessors
Downloads
Most downloaded
Technical Information (TI)
Memosens CPS91E pH sensor for heavily polluted media
English version - 10/2020
Download
Operating Instruction (BA)
BA pH sensors CPSx1E, CPFx1E ORP sensors CPSx2E, CPFx2E pH and ORP measurement
English version - 03/2026
Download
Ex Safety Instruction (XA)
XA Memosens pH/ORP sensors pH and ORP measurement
Supplement to: BA01988C, BA02142C
Safety instructions for electrical apparatus in explosion-hazardous
areas
NEPSI Ex ia IIC T3/T4/T6 Ga
NEPSI Ex ia IIC T4/T6 Ga
English version - 11/2024
Download
The CAD Drawings will be available after the configuration.
All downloads
48 Downloads
Technical Information (TI)
Most downloaded
Memosens CPS91E pH sensor for heavily polluted media
English version - 10/2020
Download
Operating Instruction (BA)
Most downloaded
BA pH sensors CPSx1E, CPFx1E ORP sensors CPSx2E, CPFx2E pH and ORP measurement
English version - 03/2026
Download
Ex Safety Instruction (XA)
XA Memosens pH/ORP sensors pH and ORP measurement
Supplement to: BA01988C, BA02142C
Safety instructions for electrical apparatus in explosion-hazardous
areas
NEPSI Ex ia IIC T3/T4/T6 Ga
NEPSI Ex ia IIC T4/T6 Ga
English version - 11/2024
Download
Ex Safety Instruction (XA)
Memosens pH/ORP sensors pH and ORP measurement
Supplement to BA01988C, BA02142C
Safety instructions for electrical apparatus in explosion-hazardous
areas
UK Ex II 1 G Ex ia IIC T3/T4/T6 Ga
UK Ex II 1G Ex ia IIC T4/T6 Ga
English version - 11/2021
Download
Ex Safety Instruction (XA)
XA Memosens pH/ORP sensors pH and ORP measurement
Supplement to BA01988C, BA02142C
Safety instructions for electrical apparatus for explosion-hazardous areas
ATEX II 1G Ex ia IIC T3/T4/T6 Ga
ATEX II 1G Ex ia IIC T4/T6 Ga
IECEx Ex ia IIC T3/T4/T6 Ga
IECEx Ex ia IIC T4/T6 Ga
English version - 01/2025
Download
Ex Safety Instruction (XA)
XA Memosens pH/ORP sensors pH and ORP measurement
EAC Ex 0Ex ia IIC T3/T4/T6 Ga X
EAC Ex 0Ex ia IIC T4/T6 Ga X
English version - 04/2025
Download
Ex Safety Instruction (XA)
Memosens pH/ORP sensors pH and ORP measurement
Supplement to: BA01988C, BA02142C
Safety instructions for electrical apparatus in explosion-hazardous
areas
NEPSI Ex ia IIC T3/T4/T6 Ga
NEPSI Ex ia IIC T4/T6 Ga
English version - 09/2021
Download
Ex Safety Instruction (XA)
XA Memosens pH/ORP sensors pH and ORP measurement
Safety instructions for electrical apparatus in explosion-hazardous
areas
English version - 11/2024
Download
Ex Safety Instruction (XA)
Memosens pH/ORP sensors pH and ORP measurement
Supplement to BA01988C, BA02142C
Safety instructions for electrical apparatus in explosion-hazardous
areas
KOR Ex ia IIC T3/T4/T6 Ga
KOR Ex ia IIC T4/T6 Ga
English version - 10/2021
Download
Ex Safety Instruction (XA)
Memosens pH/ORP sensors pH and ORP measurement
Safety instructions for electrical apparatus in explosion-hazardous
areas
English version - 04/2021
Download
Ex Safety Instruction (XA)
XA Memosens pH/ORP sensors Safety instructions for electrical apparatus in explosion-hazardous areas
CSA C/US IS Cl. I Div. 1 GP A-D T3/T4/T6 + CSA C/US IS Cl. I Zone 0 AEx ia IIC T3/T4/T6
CSA C/US IS Cl. I Div. 1 GP A-D T4/T6 + CSA C/US IS Cl. I Zone 0 AEx ia IIC T4/T6
CSA C/ US Cl. 1 Div 1&2 GP A-D T6…T3
English version - 05/2026
Download
Ex Safety Instruction (XA)
Memosens pH/ORP sensors pH and ORP measurement
Safety instructions for electrical apparatus in explosion-hazardous
areas
English version - 04/2021
Download
Fields of Activities (FA)
Sensors, transmitters, compact devices and assemblies Experts in Liquid Analysis
English version - 02/2026
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)
Sıvı analizinde uzmanlık Sensörlerden komple anahtar teslim çözümlere
Turkish version - 11/2023
Download
Fields of Activities (FA)
Expertise in liquid analysis From sensors to complete turnkey solutions
English version - 09/2022
Download
Fields of Activities (FA)
Sensoren, Messumformer, Kompaktgeräte and Armaturen Kompetenz in der Flüssigkeitsanalyse
German version - 02/2026
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)
Sensori, trasmettitori, dispositivi compatti e armature Sensori, trasmettitori,
dispositivi compatti e armature
Esperti in materia di analisi dei
liquidi
Italian version - 06/2026
Download
Competence Brochure (CP)
pH-Messung in Industrieprozessen Auswahl- und Engineering-Hilfe für verschiedene Industriebranchen und
Applikationen
German version - 12/2021
Download
Competence Brochure (CP)
pH 測定セレクションガイド 産業プロセスにおけるpH測定
Japanese version - 06/2026
Download
Competence Brochure (CP)
pH measurement in industrial processes Selection and engineering guide for different industries and
applications
English version - 12/2021
Download
Case Study (CS)
Die Zukunft des Bergbaus Automatisierung und Effizienz in der Nickel- und Kobaltgewinnung
German version - 04/2025
Download

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Memosens CPS91E - Digital pH sensor for chemical processes, paper or paint production
Memosens CPS91E digital pH sensor

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Spare parts and accessories

further parts
further parts

Kit CPSxx protective caps

further parts
further parts
Order code 71538217

Memoclip label Memosens sensor

Order code 71038228

Memoclip label memosens cable

Order code 71038229

KCL-Electrolyte solution CPY4

Order code CPY4-
Spare parts & accessories

Selection of compatible products

/