Memosens CPS97E

Summary

Product Identification

• Product Name: Memosens CPS97E
• Sensor Type: ISFET sensor for pH measurement
• Technology: Memosens 2.0

Application

This sensor is designed for contaminated media, including those with solids, emulsions, and precipitation reactions. It is suitable for process applications involving:

• Rapidly changing pH values
• Varying temperatures and pressures
• Water treatment and wastewater

It is approved for use in hazardous areas with the following certifications: ATEX, IECEx, CSA C/US, NEPSI, JPN Ex, INMETRO, UKCA, and Korea Ex.

Key Features and Benefits

• Durability: Break-resistant construction.
• Reference System: Open junction with stabilized hard gel.
• Media Compatibility: Suitable for particle-laden media with high dirt load.
• Calibration: Longer calibration intervals compared to glass electrodes.
• Temperature Response: Shorter hysteresis and smaller measuring error at high temperatures.
• Accuracy: Virtually no acid and alkaline errors.
• Temperature Compensation: Integrated Pt1000 temperature sensor.
• Memosens Technology:
  • Maximum process safety via non-contact, inductive signal transmission.
  • Data security through digital transmission.
  • Ease of use: sensor data saved in the sensor.
  • Enables predictive maintenance by recording sensor load data.

Measuring Principle

The CPS97E utilizes an Ion-Selective Field-Effect Transistor (ISFET) as an alternative to traditional glass electrodes for pH measurement. The ISFET sensor's gate insulator layer is pH-selective, interacting with H⁺ ions in the medium to generate an electric field. This field controls a conductive channel in the silicon substrate, producing an output signal proportional to the ion concentration, governed by the Nernst equation.

Measuring System Components

A complete measuring system includes:

• ISFET sensor (Memosens CPS97E)
• Memosens data cable (e.g., CYK10)
• Transmitter (e.g., Liquiline CM44x, CM42)
• Assembly (e.g., Dipfit CPA111, Flowfit CPA250, Cleanfit CPA871, Unifit CPA842)
• Optional: Automatic cleaning and calibration system (e.g., Liquiline Control CDC90)

Data and Communication

• Digital Transmission: Connects exclusively to transmitters with Memosens technology. Analog transmitters are not compatible.
• On-Sensor Data Storage: Stores manufacturer data, calibration records, operating data, sensor load, and more.
• Data Accessibility: Data can be displayed using Liquiline CM42, CM44x, and Memobase Plus CYZ71D.
• Reliability: Integrated electronics store calibration data and operating history. Calibration can be performed independently of the measuring point. Sensor data allows for accurate maintenance scheduling and predictive maintenance.
• Interference Immunity: Digital transmission via a non-contact connection is free from potential interference. Failures or connection interruptions are reliably detected and reported.

Safety

• Process Safety: Inductive, non-contact measured value transmission eliminates moisture-related issues like corrosion and distorted readings.
• Galvanic Decoupling: Transmitter is galvanically decoupled from the medium.
• EMC: Guaranteed by screening measures for digital transmission.
• Hazardous Areas: Intrinsically safe electronics allow operation in hazardous areas with appropriate Ex approvals.

Technical Specifications

Input

• Measured Variables:
  • pH value
  • Temperature
• Measuring Range:
  • pH: 0 to 14 pH
  • Temperature: –15 to 110 °C (5 to 230 °F)

Performance Characteristics

• Reference Conditions:
  • Temperature: 25 °C (77 °F)
  • Pressure: 1013 hPa (15 psi)
• Reference System: Ag/AgCl reference lead, stabilized bridging electrolyte gel.
• Measured Error (pH 1 to 13): Average Δ pH 0.02 at 25 °C (77 °F).
• Repeatability: ± 0.01 pH
• Reaction Time:
  • Voltage interruption (sensor in medium): 3-5 minutes
  • Liquid film interruption: 5-8 minutes
  • Dry storage: up to 30 minutes
• Response Time (t<0xE2><0x82><0x90>): < 5 seconds (for a buffer change from pH 4 to pH 7 under reference conditions).

Process Limits

• Process Temperature Range: –15 to 110 °C (5 to 230 °F).
  • Note: Limited operating life in certain high-temperature/alkaline conditions (see Figure 9).
• Process Pressure Range: 0.8 to 11 bar (11.6 to 159.5 psi) absolute.
• Minimum Conductivity: > 500 μS/cm.
• Pressure/Temperature Rating: Maximum 11 bar (160 psi) absolute at 100 °C (212 °F).

Mechanical Construction

• Sensor Shaft Material: PEEK
• Seal Material: FFKM
• O-ring Material: FKM
• Process Coupling Material: PPS, fiberglass-reinforced
• ISFET Chip Material: Metal oxide based on tantalum pentoxide
• Temperature Sensor: Pt1000 (Class A according to DIN IEC 60751)
• Plug-in Head: Memosens plug-in head, pressure resistance 16 bar (232 psi) relative.
• Process Connections: Pg 13.5
• Surface Roughness: Ra < 0.76 µm (30 µin)
• Weight: Varies by installed length (35 g to 66 g).
• Installed Lengths: 120 mm, 225 mm, 360 mm.

Environmental Conditions

• Ambient Temperature Range: Not below –15 °C (5 °F).
• Storage Temperature: 0 to 50 °C (32 to 122 °F).
• Sensitivity to Light: ISFET chip is sensitive to light; avoid direct sunlight during calibration and operation.
• Degree of Protection: IP 68 (10 m water column, 25 °C, 45 days).

Electromagnetic Compatibility (EMC)

• Interference emission and immunity as per EN 61326-1, EN 61326-2-3, and NAMUR NE21.

Mounting

• Orientation: ISFET sensors can be installed in any position. However, upside-down installation may risk air bubbles interrupting electrical contact. Recommended orientation is at an angle of approx. 30 to 45° to the direction of flow.
• Installation Torque: 3 Nm (2.21 lbf ft) when installing in Endress+Hauser assemblies.
• Note: ISFET sensors are not designed for abrasive media. Avoid direct flow to the chip in such applications.

Certificates and Approvals

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

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