Endress+Hauser CLS21D Specifications

TI00085C/07/EN/15.18 71392467

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Technical Information

Condumax CLS21D/CLS21

Conductivity sensors, analog or digital with Memosens technology

Cell constant k = 1.0 cm

Application

Measurement in media with average or high conductivity:

• Separation of media with average conductivity (milk/water)

• Separation of media with high conductivity (alkali/water)

• Drinking water treatment

• Wastewater treatment Sensors with temperature probes are used in conjunction with conductivity

measuring devices that support automatic temperature compensation:

• Liquiline CM442/CM444/CM448 (only CLS21D)

• Liquiline CM42

• Liquiline CM14 (only CLS21D)

• Liquisys CLM223/253 (only CLS21) The resistivity in MΩ · cm can also be measured using these transmitters.

Your benefits

• Different designs for optimum adaptation to the process or mounting location

• Installation in pipe or flow assembly

• Compact design

• With plug-in head (IP68 (CLS21D), IP65 (CLS21)) or fixed cable (IP67)

• High chemical, thermal and mechanical resistance

• Manufacturer inspection certificate stating the individual cell constant

Other advantages of Memosens technology

• Maximum process safety thanks to non-contact, inductive signal transmission

• Data security thanks to digital data transmission

• Very easy to use as sensor data saved in the sensor

• Recording of sensor load data in the sensor enables predictive maintenance

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Function and system design

Condumax CLS21D/CLS21

Measuring principle

Measuring system

Conductivity of liquids is determined with a measuring arrangement where two electrodes are located in the medium. An alternating voltage that causes a current to flow through the medium is applied at these electrodes. The electrical resistance, or its reciprocal value - conductance G - is calculated based on Ohm's law. The specific conductance κ is determined from the conductance value using the cell constant k, which depends on the sensor geometry.

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 1 Conductive measurement of conductivity

AC Alternating voltage source I Current intensity measurement U Voltage measurement

A complete measuring system comprises the following components at least:

• The conductively measuring conductivity sensor CLS21D or CLS21

• A transmitter, e.g. Liquiline M CM42

• A measuring cable, e.g. Memosens data cable CYK10 or CYK71 for analog sensors

 2 Example of a measuring system (with Memosens sensor)

1 Liquiline M CM42 transmitter 2 Memosens data cable 3 Condumax CLS21D

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A0024376

Condumax CLS21D/CLS21

Communication and data processing (only CLS21D)

Communication with the transmitter

Always connect digital sensors with Memosens technology to a transmitter with Memosens technology. Data transmission to a transmitter for analog sensors is not possible.

Digital sensors can store measuring system data in the sensor. These include the following:

• Manufacturer data – Serial number – Order code – Date of manufacture

• Calibration data – Calibration date – Cell constant – Delta cell constant – Number of calibrations – Serial number of the transmitter used to perform the last calibration

• Operating data – Temperature application range – Conductivity application range – Date of initial commissioning – Maximum temperature value – Hours of operation at high temperatures

Reliability

Maintainability

Integrity

Dependability (only CLS21D)

Memosens technology digitizes the measured values in the sensor and transmits the data to the transmitter using a non-contact connection that is free from potential interference. The result:

• Automatic error message if sensor fails or connection between sensor and transmitter is interrupted

• Immediate error detection increases measuring point availability

Easy handling

Sensors with Memosens technology have integrated electronics that store calibration data and other information (such as total hours of operation and operating hours under extreme measuring conditions). Once the sensor has been connected, the sensor data are transferred automatically to the transmitter and used to calculate the current measured value. As the calibration data are stored in the sensor, the sensor can be calibrated and adjusted independently of the measuring point. The result:

• Easy calibration in the measuring lab under optimum external conditions increases the quality of the calibration.

• Pre-calibrated sensors can be replaced quickly and easily, resulting in a dramatic increase in the availability of the measuring point .

• Maintenance intervals can be defined based on all stored sensor load and calibration data and predictive maintenance is possible.

• The sensor history can be documented on external data carriers and in evaluation programs. Thus, the current application of the sensors can be made to depend on their previous history.

With inductive transmission of the measured value using a non-contact connection, Memosens guarantees maximum process safety and offers the following benefits:

• All problems caused by moisture are eliminated. – Plug-in connection remains free from corrosion – Measured value distortion from moisture is not possible. – The plug-in system can even be connected under water.

• The transmitter is galvanically decoupled from the medium.

• EMC safety is guaranteed by screening measures for the digital transmission of measured values.

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Input

GN/YE

GND

–

Com A

Com B

GN/YE

Outer shield (see wiring diagram of transmitter)

GN WH

Pt 100

Coax BK Coax inner

shield (outer electrode)

BN n.c.

conductivity (inner electrode)

}

Cable GY

Sensor Plug

)

}

Condumax CLS21D/CLS21

Measured values

• Conductivity

• Temperature

Measuring ranges

Conductivity (in relation to water at 25 °C (77 °F))

CLS21D / CLS21 10 μS/cm to 20 mS/cm

Temperature

CLS21D CLS21

Cell constant

Temperature compensation

CLS21D / CLS21

NTC 30K (CLS21D)

Pt100 (Class B as per IEC 60751) (CLS21)

Power supply

Electrical connection CLS21D

The electrical connection simulator to the transmitter is established using measuring cable CYK10.

-20 to 100 °C (-4 to 212 °F)

-20 to 135 °C (-4 to 275 °F)

k = 1.0 cm–1, nominal

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 3 Measuring cable CYK10

CLS21

The sensor is connected via the fixed cable or the CYK71 measuring cable with shield. The wiring diagram is provided in the Operating Instructions of the transmitter used.

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 4 Measuring cable CYK71

A compatible cable connector is included in the delivery for the plug-in head versions. You must terminate the CYK71 cable (not included in the delivery) with the cable connector at the sensor end according to the connection diagram above.

A VMB junction box and another CYK71 cable are required for the cable extension.

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Condumax CLS21D/CLS21

Performance characteristics, general

Uncertainty of measurement

Response time

Maximum measured error

Repeatability

Installation instructions

Each individual sensor is factory-measured in a solution of approx. 5 mS/cm (CLS21D) or approx. 500 µS/cm (CLS21) using a reference measuring system traceable to NIST or PTB. The exact cell constant is entered into the manufacturer inspection certificate supplied. The uncertainty of measurement in determining the cell constant is 1.0 %.

Performance characteristics (only CLS21D)

Conductivity Temperature t90 ≤ 296 s

5% of reading

0.2% of reading

t95 ≤ 3 s

Installation

The sensors are installed directly via the process connection. As an option, the sensor can also be installed via a flow assembly (see "Accessories").

 5 Installation in flow assembly CLA751

A0019019

 6 Installation in flow assembly CLA752

A0035650

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