Memosens CPS77E

Summary

Product identification

• Product: Memosens CPS77E
• Type: ISFET sensor for pH measurement
• Technology: Memosens 2.0

Application

• Hygienic and sterile applications
• Food and pharmaceutical industry
• Biotechnology
• Hazardous areas (Zone 0, 1, and 2) with approvals including ATEX, IECEx, CSA C/US, NEPSI, JPN Ex, INMETRO, UKCA, and Korea Ex.

Key Benefits

• Break-resistant construction.
• Biocompatibility tested (in vitro and in vivo) according to USP <87> and USP <88> Cl. VI.
• Sterilizable.
• Longer calibration intervals compared to pH glass electrodes.
• Shorter hysteresis during temperature changes.
• Reduced measuring errors after exposure to high temperatures.
• Virtually no acid and alkaline errors.
• Integrated Pt1000 temperature sensor for compensation.
• Memosens Technology Benefits:
  • Maximum process safety via non-contact, inductive signal transmission.
  • Digital data transmission ensures data security.
  • Sensor data (calibration, load, operating data) saved in the sensor for easy use and predictive maintenance.

Measuring Principle

• Utilizes Ion-Selective Field-Effect Transistors (ISFET) as an alternative to glass electrodes for pH measurement.
• ISFETs are based on MOS transistor principles but replace the metal gate with direct contact between the medium and the gate insulator layer.
• A conductive channel forms in the silicon substrate, allowing current to flow between the "Source" and "Drain" electrodes, controlled by the gate potential generated by ions in the medium.
• The gate insulator is ion-selective for H⁺ ions, undergoing reversible surface reactions based on the medium's acidity or alkalinity, which controls the field effect and thus the pH measurement.
• The relationship between the gate-source voltage (UGS) and ion activity follows the Nernst equation.

Measuring System Components

A complete system includes:

• ISFET sensor (Memosens CPS77E)
• Memosens data cable (e.g., CYK10)
• Transmitter (e.g., Liquiline CM44x, CM42)
• Assembly (e.g., immersion, flow, retractable, permanent installation)
• Optional: Automatic cleaning and calibration system (e.g., Liquiline Control CDC90)

Communication and Data Processing

• Digital sensors with Memosens technology must be connected to Memosens-compatible transmitters.
• Sensors store various data, including: manufacturer details, serial number, order code, manufacturing date, calibration data, operating data, sensor load, and history.
• This data can be viewed with transmitters like Liquiline CM42/CM44x or Memobase Plus CYZ71D.

Dependability

• Integrated electronics store calibration and operational data, enabling independent calibration in a lab and quick sensor replacement.
• Predictive maintenance is possible due to accurate tracking of sensor load and history.
• Digital transmission is interference-immune, ensuring data security and reliable detection of sensor or connection failures.

Input

• Measured Variable: pH value, Temperature
• Measuring Range:
  • pH: 0 to 14
  • Temperature: –15 to 135 °C (5 to 275 °F)

Performance Characteristics

• Reference Operating Conditions: 25 °C (77 °F), 1013 hPa (15 psi)
• Reference System: Ag/AgCl reference lead, liquid KCl 3M, AgCl-free bridging electrolyte.
• Hysteresis: Lower acid/alkaline errors compared to glass electrodes. Average error between pH 1 and 13 is Δ pH 0.02 (at 25 °C).
• Repeatability: ± 0.01 pH
• Response Time:
  • Settling time (after voltage interruption, sensor in medium): 3-5 minutes
  • Settling time (after interruption of liquid film): 5-8 minutes
  • Settling time (after dry storage): up to 30 minutes
  • t<0xE2><0x82><0x90> (buffer change pH 4 to 7 under reference conditions): < 5 seconds. Response of the integrated temperature sensor can be slower with extreme temperature changes.

Mounting and Installation

• Orientation: ISFET chip should be positioned at approx. 30-45° to the direction of medium flow.
• ISFET sensors are not designed for abrasive media.
• Can be installed in any position; upside-down installation may risk air bubbles in the reference system.
• Recommended installation angle: approximately 30-45° to the medium flow.
• Maximum continuous sensor operation in dry conditions: 6 hours.
• Installation Torque: Hand-tighten with 3 Nm (2.21 lbf ft) when using Endress+Hauser assemblies.
• Hygienic Requirements: For hygienic applications, use certified process assemblies, ensure self-draining installation, and avoid dead areas. Sensor replacement recommended after 40 CIP cycles.

Environmental Limits

• Ambient Temperature Range: –15 to 50 °C (5 to 122 °F). Avoid temperatures below –15 °C to prevent frost damage.
• Storage Temperature: 0 to 50 °C (32 to 122 °F).
• Sensitivity to Light: Avoid direct sunlight during calibration and operation, as the ISFET chip is light-sensitive.
• Degree of Protection: IP 68 (10 m water column for 45 days at 25 °C).
• Electromagnetic Compatibility (EMC): Complies with EN 61326-1, EN 61326-2-3, and NAMUR NE21.

Process Limits

• Process Temperature Range: –15 to 135 °C (5 to 275 °F). Operation at high temperatures, especially with strong alkalis, can reduce sensor operating life.
  • Area A: No problems.
  • Area B: Limited operating life.
  • Area C: Use not recommended.
• Process Pressure Range: 0.8 to 11 bar (11.6 to 159.5 psi) absolute.
• Conductivity (Minimum): 50 μS/cm (under reference conditions).
• Pressure-Temperature Ratings:
  • Maximum: 11 bar (160 psi) absolute / 100 °C (212 °F)
  • Sterilizable: 4 bar (58 psi) absolute / 135 °C (275 °F) for 1 hour.

Mechanical Construction

• Dimensions: Available in installed lengths of 120 mm (4.72 in), 225 mm (8.86 in), and 360 mm (14.17 in).
• Weight: Ranges from 35 g (1.2 oz) to 66 g (2.3 oz) depending on length.
• Materials:
  • Sensor Shaft: PEEK
  • Seal: FFKM
  • O-ring: FKM
  • Process Coupling: PPS, fiberglass-reinforced
• Resistance to Breaking: High due to PEEK shaft.
• Temperature Sensor: Pt1000 (Class A according to DIN IEC 60751).
• Plug-in Head: Memosens plug-in head (pressure resistant to 16 bar relative).
• Process Connections: Pg 13.5
• Surface Roughness: Ra < 0.76 µm (30 µin).

Accessories

• Assemblies: Unifit CPA842, Cleanfit CPA875, Dipfit CPA111, Cleanfit CPA871, Cleanfit CPA450, Flowfit CPA250.
• Cleaning and Calibration System: Liquiline Control CDC90.
• Buffer Solutions: CPY20.
• Measuring Cables: Memosens data cable CYK10, Memosens laboratory cable CYK20.
• Handheld Instrument: Liquiline Mobile CML18.

Certificates and Approvals

• Current certificates and approvals can be found on the relevant product page at www.endress.com.

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Disclaimer: This extraction may miss figures, footnotes, or revisions. Contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror