ELMETRON CP-511 User manual

LABORATORY pH-METER
CP-511
USER‘S MANUAL

USER‘S MANULAL
WATERPROOF pH-METER
CP-511
Before starting work please read the instruction carefully.

CONTENTS
I. INTRODUCTION 1
1. Exploitation notices 3
2. Characteristics of the meter 4
3. What is the meter designed for 5
4. The outside view 6
5. Switching the meter on and off 9
6. Preparation to work 10
6.1. Choosing the kind of temperature compensation 10
II. pH MEASUREMENT 11
7. Preparation of the pH electrode 13
8. Calibration 14
8.1. Calibration with automatic temperature compensation 15
8.2. Calibration with manual temperature compensation 16
9. The electrode parameters readout 17
10. pH measurement 19
10.1.Measurement with automatic temperature compensation 19
10.2.Measurements with manual temperature compensation 20
11. Notices about the temperature compensation and interpretation
of the measurement results 21
III. REDOX POTENTIAL AND TEMPERATURE MEASUREMENT 23
12. Redox potential measurement 25
13. Temperature measurement 25
IV. OTHER 27
14. Readout of the software version number 28
15. Technical data 29
16. Equipment 30

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I. INTRODUCTION

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User‘s manual for CP-511 pH meter v1.10

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1. Exploitation notices
Dear User!
We present you a device distinguished by accuracy according to the
technical data and by a high stability of the displayed results. We believe that
the measurements will not cause you any trouble and that the meter will
operate without any inconvenience. Wide range of additional functions
requires careful reading of the manual, in other case some of the
features may stay unused or using the meter may be troublesome.
Employing of good-quality electrodes and replacing them after a suitable time
ensures obtaining high measuring parameters. We want to call your attention
to the fact, that this equipment has a much shorter working life than the
meter. Typical symptoms of an improper operation of the electrode are:
deterioration of final result stability and its flowing as well as significant
measuring error. Part of the users has problems arising from employing
electrodes not being preconditioned before the measurement or making
measurements without removing the shielding ring from the liquid
junction or with a plugged junction. To avoid such situations it is
necessary to choose a proper kind of electrode for solutions which are going
to be measured e.g. special electrodes for the sewage, liquids with deposits,
meat cheese etc. Therefore, if you observe improper operation of the device,
please take control measurements with another electrode or check the used
electrode with another pH-meter. Generally, the deterioration of the
meter’s work is caused by the electrode and not by the meter.
The essential feature of our products is their low failure frequency. However,
if your meter fails, our firm will immediately perform its warranty repair.
We wish pleasant and trouble-free work with our meter.

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User‘s manual for CP-511 pH meter v1.10
2. Characteristics of the meter
The CP-511 pH meter belongs to the newest generation of measuring
devices which offer wide range of additional functions. The meter ensures
high accuracy and repeatability of the readings and is easy in use.
Electronic elements of the newest generation used in the meter have made
its memory independent from power supply.
The meter is equipped with large custom LCD display, which displays the pH
or redox potential and temperature reading.
Main features of CP-511 are:
-high accuracy and stability of readings;
-automatic temperature compensation;
-pH electrode calibration in 1 to 3 points;
-automatic recognition of pH buffers and standards;
- storage of the standard solutions values;
- the electrode slope is stored in the memory independently from power
supply;
-information about the pH electrode condition.

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3. What is the meter designed for
CP-511 pH meter is a precise and easy-to-use laboratory device designed for
measuring hydrogen ion concentration in pH units, redox potential in mV units
and temperature of solutions or air in °C.
Depending on the type of applied pH electrode, the CP-511 pH meter is being
used in food, chemical, pharmaceutical and power industries, in water
treatment stations, laboratories, agriculture, universities, scientific laboratories
etc.
The meter is prepared to work with all types of combination pH electrodes and
redox electrodes equipped with BNC-50 connector. It is possible to connect
the meter with two electrodes (measuring and reference) by special adapter
offered as additional equipment. CP-511 pH meter cooperates with Pt-1000
temperature probe equipped with Chinch connector.

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User‘s manual for CP-511 pH meter v1.10
4. The outside view
On the front wall of the meter there is an LCD display (Pic. 1) which,
depending on the chosen function, shows:
-the pH readout in pH units;
-the redox potential readout in mV.
The measurement function is chosen by pressing appropriately marked
button and is signalised with lighting diode placed above the button.
Simultaneously with the readout the temperature value in
0
C is displayed.
Symbols of units are displayed next to the readout.
Pic. 1
Next to the temperature reading the symbol is displayed: - the symbol for
automatic temperature compensation or - the symbol for manual
temperature compensation. The CAL symbol in the left on the display
signalises that the meter is in the calibration mode. In the MODE mode it is
possible to check the electrode parameters verified during the last calibration.

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The meter’s keyboard (Pic. 2) is equipped with the following buttons:.
- switching the meter on and off;
- choosing the pH measurement;
-choosing the mV measurement;
- holding this button in the measurement function enters the
calibration mode; pressing shortly in this mode confirms the calibration
result;
, - buttons used for entering parameters.
In the upper wall of the meter there are inputs placed with the symbols given
below:
pH/mV –the BNC-50 connector for the combination or measuring pH
electrode or redox electrode;
Gnd – the connector for the reference electrode;
temp – the Chinch connector for the temperature probe;
POWER – the power adapter connector.

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User‘s manual for CP-511 pH meter v1.10
Pic. 2

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5. Switching the meter on and off
After switching it on with the button, the meter tests the memory and the
display on which all symbols are displayed (pic. 3).
Pic. 3.
If the test ends successfully, after about 1.5 s the meter switches
automatically to the measuring mode, in which it was switched off. If the
sign is displayed, it means that the meter has lost the factory settings
and requires service. If after 1,5 s all symbols are continuously displayed, it
informs that the calibration parameters of the electrode have been lost.
After pressing the button the meter adopts standard parameters:
-drift = 0 pH, slope = 100%
and enters the measuring mode. It will be necessary to calibrate the pH
electrode.
The meter is switched off by pressing the button.

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User‘s manual for CP-511 pH meter v1.10
6. Preparation to work
Before starting work:
- connect the power adapter plug to the Power connector;
-connect the combination pH electrode or the redox electrode to the
pH/mV connector (BNC-50);
-in case of using a measuring and reference electrode connect them with
use of the adapter, available optionally;
-connect the temperature probe to the ttemperature connector (Chinch);
- switch the meter on by pressing the button.
6.1. Choosing the kind of temperature compensation
The meter switches to the automatic temperature compensation mode after
connecting the temperature probe. Next to the reading the symbol is
displayed. The measurement will be compensated to the value of
temperature measured by the probe.
Disconnecting the temperature probe switches the meter to the manual
temperature compensation mode (the symbol disappears and the
symbol appears). At the same time the , buttons will be unlocked,
what enables the temperature value changing.
Note: pressing the , buttons simultaneously will set the
compensation temperature to 20
0
C.

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II. pH MEASUREMENT

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User‘s manual for CP-511 pH meter v1.10

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7. Preparation of the pH electrode
The electrode should be prepared to work according to the manufacturer’s
instructions. If the instructions weren’t given please follow the steps:
-new electrode should be put into saturated KCl solution for about 5 hours:
-before starting measurements, protecting rings (if used in this kind of
electrode) should be removed. The ring placed on the junction – the lower
part of the electrode - should be removed upwards along the electrode’s
body and the upper, which protects the KCl refilling hole, downwards
along the body. Removing the lower ring is essential, in other case the
electrode won’t measure. The upper ring should be removed during
measurements of high-temperature solutions or to protect the junction
during measurements in solutions with deposits or oils. Sometimes
instead of ring a cork is used;
-during measurements in laboratory it is advisable to use an electrode
holder;
-after every measurement the electrode should be washed in distilled
water;
-excess of liquid on the electrode should be removed by gentle touching
the glass with a tissue paper;
-after work the electrode should be stored in the KCl solution. Protecting
rings should be put on the junction and the upper hole;
-in case of long breaks between measurements the electrode should be
stored, after drying, in the packaging;
-after taking the electrode out of the package the deposit, which is likely to
appear, should be removed with use of water;
-before use, the electrode should be placed in saturated KCl solution for
about 1 hour;
-if the construction of the electrode enables refilling the electrolyte, it
should be controlled and refilled periodically by the upper hole in the
electrode’s body (usually as the electrolyte a KCl solution is used).
-If the electrode is equipped with a small container (bottle) put on its end,
the bottle should be taken off before measurements by unscrewing the nut
gently and taking the bottle down the electrode’s body. After the
measurements the bottle should be put on again. Such electrodes are not
equipped with the protective ring on the junction and do not require
activating the membrane.
Note: storing the electrode in distilled water shortens its life span and
may heighten the measurement error.

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User‘s manual for CP-511 pH meter v1.10
8. Calibration
Before starting measurement with new electrode, after long-lasting use or
before making measurements which require high accuracy the electrode
connected with the meter should be calibrated. Results of measurements
made without calibration will be burdened with a significant error. Calibration
is made in buffer solutions. It consists in comparing pH value of buffer
solutions with the value displayed by the meter and next in automatic
introduction of correction which is taken into consideration during next
measurements. Calibration should be periodically repeated because the
parameters of the electrode are changing while working, what influences
accuracy. The frequency of this procedure depends on the demanded
accuracy, number of the measurements carried out, conditions in which the
electrode was used, temperature and value of the measured solutions. When
the highest accuracy is required, it is recommended to use fresh buffer
solutions with certificates.
CP-511 enables calibration in buffer solutions with values determined by
the manufacturer, which are: 4.00; 7.00 and 10.00 pH, and are
automatically detected.
There is a possibility of calibration minimum in 1 point and maximum in 3
points. The more calibration points are used, the higher accuracy in the
whole range is ensured.
Calibration at 1 point does not ensure high accuracy. If the accuracy
requirements are not very high and the measurement is made in the whole
measuring range one-point calibration should be made with use of 7.00 pH
buffer solution. Thanks to this the error connected with so called “zero offset”
of the electrode will be eliminated.
At the rest of the points standard electrode’s slope parameters from the
meter’s memory will be adopted. This slope corresponds to the theoretical
efficiency of pH electrode. In case of accurate measurements in the whole
range we recommend three-point calibration. In case of measurements in
acids calibration in 2 buffer solutions: 4.00 and 7.00 pH is recommended, in
case of alkali measurements calibration in 7.00 and 10.00 pH buffers is
advisable.
In CP-511 the slope of the electrode is approximated in segments between
the calibration points.
Starting the calibration process irreversibly erases the calibration data
stored in the memory.
The buffer solutions may be used in a freely chosen order.