TI01496C/07/EN/02.21
71518514
2021-03-08

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Memosens CPS71E
pH sensor for chemical process applications

Digital with Memosens 2.0 technology
With poison-resistant reference thanks to ion trap
Application
Process technology and monitoring of processes with:• Rapidly changing pH values• High proportion of electrode poisons such as H2SWith ATEX, IECEx, CSA C/US, NEPSI, Japan Ex and INMETRO approvals for use inhazardous areas Zone 0, Zone 1 and Zone 2.
Your benefits• Very long service life thanks to poison-resistant reference with improved ion trap
• Bridging electrolyte free of silver ions, acrylamide-free• TP reference system with pressurized reference, for chemical processes with highconcentrations of reference poisons• TU reference system for upside-down installation, solidified gel in the internalreference lead
• Integrated NTC 30K temperature sensor for effective temperature compensation• Choice of 1 or 3 ceramic junctions (TB and TC reference system)
Other advantages provided by 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 are saved in the sensor• Predictive maintenance can be performed with the Memobase Plus CYZ71D byrecording sensor load data in the sensor

Memosens CPS71E

Function and system design
Measuring principle

pH measurement
The pH value is used as a unit of measurement for the acidity or alkalinity of a medium. The
membrane glass of the electrode delivers an electrochemical potential that depends on the pH valueof the medium. This potential is generated by the selective accumulation of H+ ions on the outerlayer of the membrane. As a result, an electrochemical boundary layer with an electrical potential
difference forms at this point. An integrated Ag/AgCl reference system serves as the requiredreference electrode.
The measured voltage is converted to the corresponding pH value using the Nernst equation.

Measuring system

A complete measuring system comprises:• pH sensor CPS71E• Memosens data cable CYK10 or CYK20• Transmitter, e.g. Liquiline CM44, Liquiline CM42
• Assembly• Immersion assembly, e.g. Dipfit CPA111• Flow assembly, e.g. Flowfit CPA250• Retractable assembly, e.g. Cleanfit CPA871• Permanent installation assembly, e.g. Unifit CPA842
Additional options are available depending on the application:
Automatic cleaning and calibration system, e.g. Liquiline Control CDC90413

2A0025757

Communication and dataprocessing

2

1

Example of a measuring system for pH measurement

123
4

Retractable assembly Cleanfit CPA871
pH sensor CPS71E
Memosens data cable CYK10
Liquiline M CM42 two-wire transmitter for hazardous areas

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.

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Memosens CPS71E

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
• Slope at 25 °C (77 °F)• Zero point at 25 °C (77 °F)• Offset of integrated temperature sensor• Number of calibrations• Calibration history• Serial number of the transmitter used to perform the last calibration or adjustment• Operating data
• Temperature application range• pH application range• Date of initial commissioning• Maximum temperature value• Hours of operation under extreme conditions• Number of sterilizations• CIP counter• Sensor load
The data listed above can be displayed with Liquiline CM42, CM44x, and Memobase Plus CYZ71D.
Dependability

Reliability
Easy handlingSensors with Memosens technology have an integrated electronics unit that stores calibration dataand other information (e.g. total hours of operation or operating hours under extreme measuringconditions). Once the sensor has been connected, the sensor data are transferred automatically tothe 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 theavailability of the measuring point.
• Thanks to the availability of the sensor data, maintenance intervals can be accurately defined andpredictive maintenance is possible.
• The sensor history can be documented on external data carriers and evaluation programs, e.g.
Memobase Plus CYZ71D.
• The saved application data of the sensor can be used to determine the continued use of the sensor
in a targeted manner.
Integrity
Data security thanks to digital data transmission
Memosens technology digitizes the measured values in the sensor and transmits the data to thetransmitter via a non-contact connection that is free from potential interference. The result:• If the sensor fails or there is an interruption in the connection between the sensor and transmitter,
this is reliably detected and reported.
• The availability of the measuring point is reliably detected and reported.

Endress+Hauser

3

Memosens CPS71E

SafetyMaximum process safety
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:• No corrosion at the connection• Measured values cannot be distorted by moisture• The transmitter is galvanically decoupled from the medium. Issues concerning "symmetrical highimpedance" or "asymmetry" or the type of impedance converter are a thing of the past.
• Electromagnetic compatibility (EMC) is guaranteed by screening measures for the digitaltransmission of measured values.
• Intrinsically safe electronics mean operation in hazardous areas is not a problem. Complete
flexibility thanks to individual Ex approvals for all components, such as sensors, cables andtransmitters.

Input
Measured variable

pH value
Temperature

Measuring range

Application B• pH: 0 to 14• Temperature: 0 to 140 °C (32 to 284 °F)
Application H• pH: 0 to 12• Temperature: 0 to 140 °C (32 to 284 °F)
Pay attention to the operating conditions in the process.

Power supply
Electrical connection

GY GNDYE Com B
GN Com A
WH –BN +EY/NG

A0024019

2Measuring cable CYK10 or CYK20‣ Connect the Memosens measuring cable, e.g. CYK10 or CYK20 to the sensor.
For further information on cable CYK10, see BA00118C

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Memosens CPS71E

Performance characteristics
Reference system

TB and TC reference system:
TP reference system:

TU reference system:

Ag/AgCl reference lead with ion trap, reference and bridging
electrolyte 3 M KCl, acrylamide-free, flowable gel electrolyte
Ag/AgCl reference lead with ion trap, reference and bridging
electrolyte 3 M KCl, acrylamide-free, flowable gel electrolyte,pressurized 7 bar (102 psi) (absolute); display via pressure
indicator
Ag/AgCl reference lead with ion trap, reference and bridging
electrolyte 3 M KCl, acrylamide-free, solidified gel electrolyte

Pay attention to the operating conditions in the process.

Installation
Orientation

TB, TC and TP reference system• Do not install the sensors upside-down.
• The angle of inclination from the horizontal must be at least 15°.
An installation angle < 15° is not permitted, as otherwise an air bubble will form. Contact between
the reference and membrane glass is then no longer guaranteed.

A15°

15°
B

A0028039

3A
B

Installation angle at least 15° from the horizontal
Permitted orientation
Incorrect orientation

TU reference system• The sensor is suitable for upside-down installation.
• Install the sensor at any angle.

360°A0024597

4Endress+Hauser

Any installation angle

5Memosens CPS71E

Installation instructions• Before screwing in the sensor, make sure the assembly thread, the O-rings and the sealing surface
are clean and undamaged and that the thread runs smoothly.
• Pay attention to the installation instructions provided in the Operating Instructions of theassembly used.

‣ Screw in the sensor and tighten by hand with a torque of 3 Nm (2.21 lbf ft) (specifications only
apply if installing in Endress+Hauser assemblies).

TP reference system

LCAUTION
Glass sensor with pressurized reference
Possibility of sudden rupture and injury from glass splinters!
‣ Always wear protective goggles when working with these sensors.
For correct pH measurement:
1.

Before commissioning, open the modified atmosphere packaging (MAP) by pulling the red teartab.

2.

Completely remove the MAP.

3.

Remove the moistening cap with the bayonet lock.

4.

Remove the reusable protective netting from the sensor.

5.

For optimum accuracy, insert the sensor into a calibration buffer solution with pH 4 to 9 for
15 to 20 min before calibration.

6.

Put the sensor into operation.
For detailed information on removing the moistening cap, see BA01988C

Environment
Ambient temperature range

NOTICE
Risk of damage from frost!
‣ Do not use the sensor at temperatures below –15 °C (5 °F) .

Storage temperature

0 to 50 °C (32 to 122 °F)

Degree of protection

IP 68 (10 m (33 ft) water column, 25 °C (77 °F), 45 days, 1 M KCl)

Electromagnetic
compatibility (EMC)

Interference emission and interference immunity as per EN 61326-1: 2013

Process
Process temperature range

Process pressure range

6Applications B and H: 0 to 140 °C (32 to 284 °F)
Version TB, TC:
Version TU, TP (pressurizedreference):

0 to 140 °C (32 to 284 °F)
0 to 140 °C (32 to 284 °F) (140 °C (284 °F) only for sterilization)
Maximum 100 °C (212 °F) in continuous operation due toincreasing pressure loss at T > 100 °C (212 °F)

Application B:
Application H

0.8 to 14 bar (11.6 to 203 psi) absolute
0.8 to 7 bar (11.6 to 101.5 psi) absolute

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Memosens CPS71ELCAUTION
Pressurization of sensor due to prolonged use under increased process pressure
Possibility of sudden rupture and injury from glass splinters!
‣ Avoid fast heating of these pressurized sensors if they are used under reduced process pressureor under atmospheric pressure.
‣ When handling these sensors, always wear protective goggles and appropriate protective gloves.
Conductivity

10 μS/cm (at atmospheric pressure, without flow) (minimized flow; pressure and temperature mustremain constant)Pressure/temperature
ratings[psi] p [bar]203174141214511687581086429200B

Hx0204060

80

1001201403268104

140176212

248284[°C]
T[°F]A0039291-EN

5B
H
x

Endress+Hauser

Pressure/temperature ratings
Application B
Application H
Atmospheric pressure

7Memosens CPS71E

Mechanical construction

50 (1.97)

50 (1.97)

Design, dimensions

1

12

120 / 225 / 360 / 425(4.72 / 8.86 / 14.2 / 16.7)

120 / 225 / 360 / 425(4.72 / 8.86 / 14.2 / 16.7)

2

3
4

56
7
89

3

4567

Ø 11.9 (0.47)

Ø 11.9 (0.47)

A0045225

A0042541

6123456789WeightMaterials

CPS71E. Engineering unit: mm (in)Memosens plug-in head with process connection
O-ring with thrust collar
Pressure indicator (only for TP version)
Ag/AgCl reference lead with ion trap
Ion trap
Ceramic junction
Temperature sensor
pH inner lead
pH glass membrane

7CPS71E TU reference system. Engineering
unit: mm (in)

1
2
3
4
5
6
7

Memosens plug-in head with process connection
O-ring with thrust collar
Ag/AgCl reference lead with ion trap
Ceramic junction
Temperature sensor
pH inner lead
pH glass membrane

Installed length

120 mm (4.72 in)

225 mm (8.86 in)

360 mm (14.17 in)

425 mm (16.73 in)Weight40 g (1.4 oz)

60 g (2.1 oz)

90 g (3.2 oz)

100 g (3.5 oz)

Sensor shaft
pH membrane glass
Metal lead
Open apertureO-ringProcess coupling
NameplateGlass to suit process
Type B
Type N
Ag/AgCl
Ceramic junction, zirconium dioxide
FKM
PPS fiber-glass reinforced
Ceramic metal oxide

Temperature sensor

NTC 30K

Plug-in head

Memosens plug-in head for digital, non-contact data transmission, pressure resistance
16 bar (232 psi) (relative)

Process connections

Pg 13.5

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Memosens CPS71E

Certificates and approvals markThe product meets the requirements of the harmonized European standards. As such, it complies
with the legal specifications of the EU directives. The manufacturer confirms successful testing of theproduct by affixing to it the  mark.

Ex approval

ATEX
II 1G Ex ia IIC T3/T4/T6 Ga
IECEx
Ex ia IIC T3/T4/T6 Ga
NEPSI
Ex ia IIC T3/T4/T6 Ga
CSA C/US• IS Cl. I Div 1, GP A-D Ex ia IIC T3/T4/T6• IS Cl. I Zone 0, AEx ia IIC T3/T4/T6
Japan ExEx ia IIC T3/T4/T6 Ga
INMETROEx ia IIC T3/T4/T6 Ga
Hazardous area versions of the digital sensors with Memosens technology are indicated by ared/orange ring on the plug-in head.
Pay attention to the instructions for Memosens data cable CYK10 and transmitter CM82.

Additional certification

TÜV certificate for Memosens plug-in head
Pressure resistance 16 bar (232 psi) relative, minimum three times the safety pressure
EAC
The product has been certified according to guidelines TP TC 004/2011 and TP TC 020/2011 which
apply in the European Economic Area (EEA). The EAC conformity mark is affixed to the product.

Ordering information
Product pagewww.endress.com/cps71e

Product Configurator

On the product page there is a Configure button to the right of the product image.
1.

Click this button.
 The Configurator opens in a separate window.

2.

Select all the options to configure the device in line with your requirements.
 In this way, you receive a valid and complete order code for the device.

3.

Export the order code as a PDF or Excel file. To do so, click the appropriate button on the rightabove the selection window.
For many products you also have the option of downloading CAD or 2D drawings of theselected product version. Click the CAD tab for this and select the desired file type using
picklists.

Scope of delivery

Endress+Hauser

The delivery comprises:• Sensor in the version ordered• Operating Instructions• Safety instructions for the hazardous area (for sensors with Ex approval)

9Memosens CPS71E

Accessories
The following are the most important accessories available at the time this documentation wasissued.

‣ For accessories not listed here, please contact your Service or Sales Center.
Device-specific accessories

Assemblies
Unifit CPA842• Installation assembly for food, biotechnology and pharmaceutics• With EHEDG and 3A certificate• Product Configurator on the product page: www.endress.com/cpa842
Technical Information TI01367C
Cleanfit CPA875• Retractable process assembly for sterile and hygienic applications• For in-line measurement with standard sensors with 12 mm diameter, e.g. for pH, ORP, oxygen• Product Configurator on the product page: www.endress.com/cpa875
Technical Information TI01168C
Dipfit CPA140• pH/ORP immersion assembly with flange connection for very demanding processes• Product Configurator on the product page: www.endress.com/cpa140
Technical Information TI00178C
Cleanfit CPA871• Flexible process retractable assembly for water, wastewater and the chemical industry• For applications with standard sensors with 12 mm diameter• Product Configurator on the product page: www.endress.com/cpa871
Technical Information TI01191C
Cleanfit CPA450• Manual retractable assembly for installing sensors with a diameter of 12 mm and a length of
120 mm in tanks and pipes• Product Configurator on the product page: www.endress.com/cpa450
Technical Information TI00183C
Cleanfit CPA473• Stainless steel process retractable assembly with ball valve shutoff for particularly reliable
separation of the medium from the environment• Product Configurator on the product page: www.endress.com/cpa473
Technical Information TI00344C
Cleanfit CPA474• Plastic process retractable assembly with ball valve shutoff for particularly reliable separation ofthe medium from the environment• Product Configurator on the product page: www.endress.com/cpa474
Technical Information TI00345C
Dipfit CPA111• Immersion and installation assembly made of plastic for open and closed vessels• Product Configurator on the product page: www.endress.com/cpa111
Technical Information TI00112C
Flowfit CPA240• pH/ORP flow assembly for processes with stringent requirements• Product Configurator on the product page: www.endress.com/cpa240
Technical Information TI00179C

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Memosens CPS71E

Flowfit CPA250• Flow assembly for pH/ORP measurement• Product Configurator on the product page: www.endress.com/cpa250
Technical Information TI00041C
Ecofit CPA640• Set comprising adapter for 120 mm pH/ORP sensors and sensor cable with TOP68 coupling• Product Configurator on the product page: www.endress.com/cpa640
Technical Information TI00246C
Buffer solutions
High-quality buffer solutions from Endress+Hauser - CPY20
The secondary buffer solutions have been referenced to primary reference material of the PTB(German Federal Physico-technical Institute) or to standard reference material of NIST (NationalInstitute of Standards and Technology) according to DIN 19266 by a laboratory accredited by theDAkkS (German accreditation body) according to DIN 17025.
Product Configurator on the product page: www.endress.com/cpy20
Measuring cable
Memosens data cable CYK10• For digital sensors with Memosens technology• Product Configurator on the product page: www.endress.com/cyk10
Technical Information TI00118C
Memosens laboratory cable CYK20• For digital sensors with Memosens technology• Product Configurator on the product page: www.endress.com/cyk20

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