Endress+Hauser CPS16D Specifications
TI00503C/07/EN/02.14
71270268
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Technical Information
Memosens CPS16D
Combination of pH and ORP electrode with
Memosens technology
For standard applications in process technology
and environmental engineering
Poison-resistant reference with ion trap
Application
• Long-term monitoring or limit control in processes with stable process conditions
– Chemical processes
– Pulp and paper industry
– Power stations (e.g. flue gas cleaning)
– Incinerator plants
– Mining
– Wastewater
• Water treatment
– Drinking water
– Cooling water
– Well water
With ATEX, IEC, FM and CSA approval for use in hazardous areas.
Your benefits
• Simultaneous measurement of pH, ORP and rH value (in rH mode)
• Additional electrode made of platinum, for measuring reference impedance
• Low-maintenance and robust thanks to large PTFE ring junction
• Can be used at pressures up to 17 bar (246 psi), absolute
• Process glass also for very alkaline applications
• Integrated temperature sensor for effective temperature compensation
• Long service life thanks to poison-resistant reference with ion trap
• Glass breakage and blockage detection by measuring:
– Resistance of glass membrane
– Reference impedance
Other advantages of Memosens technology
• Maximum process safety owing to non-contact, inductive signal transmission
• Data security thanks to digital data transmission
• Very easy to use as sensor data saved in the sensor
• Predictive maintenance possible as sensor load data logged in the sensor
Function and system design
Memosens CPS16D
Measuring principle
pH measurement
The pH value is used as a unit of measurement for the acidity or alkalinity of a liquid medium. The
membrane glass of the electrode supplies an electrochemical potential which is dependent upon the
pH value of the medium. This potential is generated by the selective penetration of H+ ions through
the outer layer of the membrane. An electrochemical boundary layer with an electric potential forms
at this point. An integrated Ag/AgCl reference system serves as the required reference electrode.
The transmitter converts the measured voltage into the corresponding pH value using the Nernst
equation.
ORP measurement
The ORP potential is a unit of measurement for the state of equilibria between oxidizing and
reducing components of a medium. The ORP is measured using a platinum or gold electrode instead
of the pH-sensitive glass membrane. Analog to the pH measurement, an integrated Ag/AgCl
reference system is used as a reference electrode.
rH measurement
The rH value is defined as the negative logarithm of partial pressure of hydrogen in a solution. The
pH value and ORP value of a solution must be measured simultaneously to calculate the rH value.
The value is calculated using the following equation:
rH = 2 . (mV/S) + 2 pH
pH = measured pH value
mV = measured ORP value in mV + 207 mV (Ag/AgCl system)
S = slope of pH electrode
The rH value is an indicator of the oxidation or reducing ability of a process solution. The measuring
range is from 0 to 42. A process medium with rH values between 0 and 9 has a high reducing ability;
a low reducing ability with rH 9-17; an indeterminate ability with rH 17-25; a low oxidation ability
with rH 25-34, and a high oxidation ability with rH 34-42.
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Memosens CPS16D
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Measuring system
A complete measuring system comprises:
• pH/ORP combined electrode CPS16D
• Transmitter, e.g. Liquiline CM44x
• Measuring cable CYK10
• Immersion, fixed installation, flow or retractable assembly, e.g. CPA442
A0024594
1 Example of a measuring system
1 pH/ORP combined electrode CPS16D
2 Transmitter CM44x
3 Measuring cable CYK10
4 Permanent installation assembly CPA442
Communication and data processing
Communication with the transmitter
Always connect digital Memosens sensors with a combination of pH and ORP electrode to a
transmitter with the relevant functionality and Memosens technology.
Such transmitters are Liquiline CM42 (software package 9 or higher) and Liquiline CM44x (software
version 01.04.00, from 4th quarter 2012). To upgrade a Liquiline CM42 to software package 9 or
higher, the digital sensor input module FSDG1 with firmware version 1.01.01 or higher is required.
In the case of a FSDG1 with firmware version lower than 1.01.01, the sensor input module must be
replaced. Order numbers: 51518007 (non-Ex) and 51517469 (Ex). The installation of software
package 9 on the CM42 is performed using DAT CY42-S1.
The transfer of data to older transmitters, including those with Memosens capability, is possible only
to a limited extent (pH measurement only). In rare cases, it is possible that no data transfer is
performed.
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Memosens CPS16D
The digital sensors are able to store the following system data in the sensor.
• Manufacturing data
– Serial number
– Order code
– Date of manufacture
• Calibration data
– Calibration date
– Calibrated slope at 25 °C (77 °F)
– Calibrated zero point at 25 °C (77 °F)
– Calibrated offset (ORP mV measuring mode)
– Slope as % (ORP % measuring mode)
– Temperature offset
– Number of calibrations
– Serial number of the transmitter used for the last calibration
– Calibration database (stores the last 8 calibrations in the Memosens head)
• Application data
– Temperature application range
– pH application range
– ORP application range
– Date of first commissioning
– Maximum temperature value
– Operating hours at temperatures above 80 °C (176 °F) and 100 °C (212 °F)
– Operating hours at very low and very high pH values (Nernst voltage below -300 mV, above
+300 mV)
– Number of sterilizations
Reliability
Maintainability
Integrity
Maximum 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.
– Plug-in connection 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. Issues concerning "symmetrical highimpedance" or "asymmetry" or an impedance converter are a thing of the past.
• EMC safety is guaranteed by screening measures for the digital transmission of measured values.
Low-maintenance
The electrode has a sterilizable, dirt-repellent PTFE ring junction that prevents clogging, making the
electrode reliable and stable over the long term.
Data security thanks to digital data transmission
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 allow for saving calibration data
and further 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 evaluation programs at any
time. Thus, the current application of the sensors can be made to depend on their previous history.
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