WATERPROOF
OXYGEN METER
CO- 411
USER’S MANUAL
Sp. j.
41-814 Zabrze, ul. Witosa 10, POLAND
tel. +48 32 / 273 8106, tel./fax +48 32 / 2738114
www.elmetron.com.pl
e-mail: info@elmetron.com.pl
WATERPROOF
OXYGEN METER
CO-411
USER’S MANUAL
Before use, please read this instruction carefully!
WARRANTY
The “ELMETRON” company gives 24 months of
warranty
for
the
CO-411
oxygen
meter
number........................................
.
In case of damage the producer will repair the meter
within 14 days from the day of delivery.
The warranty doesn’t cover the damages caused by
usage not in conformity with the users manual, using
wrong power adapter, mechanical damages and
damages caused by repairs made by unauthorised
persons.
NOTICE: Before sending the meter to us please contact the
firm by phone.
When sending the meter, the used electrode, temperature
probe and power adapter should be also included.
Date of production...........................
Date of sale.....................................
Date of expiry..................................
Sp. j.
41-814 Zabrze - Grzybowice ul. Witosa 10
tel. (+48) 32 2738106, fax (+48) 32 2738114
POLAND
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User’s manual - CO-411 Dissolved Oxygen Meter
CONTENTS
1.
2.
3.
4.
5.
6.
Exploitation notices
Characteristic of the CO-411 oxygen meter
What is the meter designed for
Outside look
Switching the meter on and off
Preparation for work
6.1. choosing the kind of temperature compensation
7. Basic information about the oxygen measurement
8. Oxygen sensor
9. Entering the oxygen meter parameters
9.1. Salinity influence compensation
9.2. Atmospheric pressure influence compensation
9.3. Changing the unit
10. Oxygen sensor calibration
10.1. Bringing back the manufacturers characteristic
of the oxygen probe
11. Oxygen concentration measurement
11.1. Measurement with automatic temp. compensation
11.2. Measurement with manual temp. compensation
12.
13.
14.
15.
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User’s manual - CO-411 Dissolved Oxygen Meter
Temperature measurement
Power, changing the battery
Equipment
Technical data
2
3
3
4
6
7
7
8
10
10
10
12
12
13
14
15
16
16
17
18
18
19
-2-
- 19 -
Dear User!
15. TECHNICAL DATA
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. Before starting the measurements please
read this manual carefully in other case using the meter
may cause you a troubles.
Accurate dissolved oxygen measurements depend on calibration
of the sensor and regular maintenance activities – changing the
membrane, electrolyte and cleaning the electrodes. Not
performing this activities after some time may make the
measurement impossible.
We would like to turn your attention to the fact that stable
measurement is possible only when the measured solution
is flowing. Measurements in mg/l require entering the values
of atmospheric pressure and salinity, which influence the
result.
The essential feature of our products is their low failure
frequency. However if your meter will fail, our firm immediately
performs its warranty repair.
OXYGEN METER:
We wish to you a pleasant and trouble-free work with our meter.
TEMPERATURE MEASUREMENT:
range
resolution
0 ÷ 199 %
0 ÷ 19.9 mg/l
1%
0.1 mg/l
Accuracy of the measurement:
accuracy*
(±1 digit)
measurement temperature
2 %
4 %
6 %
equal to calibration temperature
±5 oC from the calibration temperature
±10 oC from the calibration temp.
Temperature compensation range:
Salinity compensation range:
Air pressure compensation range:
Sensor calibration:
2 points
or 1 point
Oxygen sensor:
0.0 ÷ 40.0 0C
0.0 ÷ 50.0 g/l
800 ÷ 1100 hPa
in 0% and 100% O2
in 100%O2
membrane, polarisation
range
resolution
accuracy*
(±1 digit)
- 50.0 ÷ 199.9 0C
0.1 0C
0.2 0C
* accuracy of the meter. Total measurement error depends on the kind of
used Pt-1000 sensor.
Temperature probe
platinum resistor Pt-1000
Accuracy of the probe in range 0 ÷ 100 0C:
with Pt1000B resistor
±0.9 0C
1
with Pt1000 /3B resistor
±0.4 0C
OTHER:
WORK TEMPERATURE:
POWER:
POWER CONSUMPTION:
DISPLAY:
DIMENSIONS:
WEIGHT:
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User’s manual - CO-411 Dissolved Oxygen Meter
-5 do 45 0C
1. battery 9V type 6F22
2. stabilised power adapter 12V
27 mW
LCD 55 x 45 mm
149 x 82 x 22 mm
220 g
- 18 13. POWER SOURCE AND CHANGING THE BATTERY
The meter is 9V battery or stabilised power adapter powered.
The adapter should be joined with the right connector in the
meter (pic. 1, no. 4). Joining the power adapter disconnects
the battery.
Displaying the
symbol informs that the battery should
be changed. To do this it is necessary to unscrew the two
screws in the lower wall of the meter pull out the whole wall
and replace the battery.
The next thing is to put the battery back into the meter and
mount the wall.
The wall on the edge has a sealing ring. It is very important to
pay attention, during closing the meter, if the ring on the whole
edge was put inside the housing. If it is correct screw the
screws till feeling the resistance (not to hard). Leaving the wall
not correctly screwed causes loosing the waterproofnes and
may cause flooding the meter and it’s destroying. This kind of
failure is not repaired on the warranty conditions.
14. EQUIPMENT
The standard set includes:
1. Oxygen sensor;
2. temperature probe Pt-1000B ( standard);
3. plastic container for the meter, temperature probe and the
sensor;
4. users manual with warranty.
As the extra equipment one may order:
1. power adapter 12V
2. temperature probe Pt1000 1/3B – higher accuracy
-32. THE CHARACTERISTICS OF THE OXYGEN METER
CO-411
The CO-411 dissolved oxygen meter belongs to the newest
generation of measuring devices with high accuracy and
repeatability of the readings and very easy operation.
Two kinds of power source - battery and power adapter
enable work in field and long-lasting measurements in the
laboratory. Thanks using the newest generation electronic
elements the meter has very low power consumption what
greatly increases the operation time on 1 battery. The meter
is equipped with large LCD display, it enables observing the
value of oxygen measurement or temperature. Waterproof
housing makes working in difficult conditions possible. Small
size and weight make working in the field easier.
Main characteristics of the CO-411 oxygen meters are:
- good accuracy and stability of the reading;
- automatic or manual temperature compensation;
- sensor calibration in 1 or 2 points;
- automatic detection of calibration points;
- automatic counting of the salinity and air pressure
influence to the result;
- storing of the oxygen sensor characteristic in non-volatile
memory;
- protection against damage caused by wrong connecting
of the battery;
- function informing with
signal about necessity of
changing the battery;
automatic switch off function.
3. WHAT IS THE METER DESIGNED FOR
The waterproof oxygen meter CO-411 is an accurate and
easy in use meter designed for oxygen dissolved in water
measurements in % or mg/l. The meter may also be used as
accurate air and liquids thermometer - measurements in 0C.
The CO-411 may be used in water treatment stations, fish
farming, chemical laboratories, scientific researches etc.
The meter is designed for cooperation with polarised oxygen
sensor with BNC-50 connector and with Pt-1000 temperature
sensor with Chinch connector.
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User’s manual - CO-411 Dissolved Oxygen Meter
-4-
- 17 -
4. OUTSIDE VIEW.
11. TEMPERATURE MEASUREMENT
On the front wall of the meter there is a large LCD display
(pic. 1) on which depending on the chosen function following
symbols are displayed:
result of the oxygen measurement in % or mg/l;
result of the temperature measurement in °C units;
or
buttons.
The measuring function is chosen with
The symbols of the units are displayed on the right side of
the results. (when measuring in mg/l there is no unit
displayed).
In case of disconnecting the temperature probe the meter
automatically switches it self to the constant temperature
compensation set by the manufacturer on 20 °C. Next to the
oxygen result a blinking symbol will appear. If the battery
should be changed a
symbol is displayed. The
keyboard placed under the display is used for switching the
meter on and off, choosing the measuring function,
calibration and freezing the result.
The keyboard has following buttons:
- switching the meter on and off;
- oxygen measurement, longer pressing in the
measuring mode causes calibrating the sensor in
automatically detected point (0% or 100%);
- temperature measurement;
,
keys used for entering the parameters.
In upper wall of the meter there are inputs with below given
symbols:
1. F - BNC-50 connector for connecting the oxygen sensor;
2. t - Chinch input for connecting the temperature probe;
3. P - Power adapter input.
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User’s manual - CO-411 Dissolved Oxygen Meter
The temperature measurement is done as follows:
- to the Chinch connector connect the temperature probe;
-
by pressing
button switch the meter on;
press the
button, by the displayed value a symbol
will appear
- put the temperature probe to the measured solution;
- wait till the stabilisation of the value on the display and
read the result.
The meter co-operates with the PT-1000 probe. Depending
on its class the accuracy of the measurement changes.
-
CAUTION:
The
blinking
199.9oC
result
during
measurements in lower temperatures informs about break in
the probe’s circuit.
The blinking –50.0oC result during measurements in higher
(positive) temperatures informs about short circuit in the
probe’s circuit.
- 16 -
-5-
11.1. Measurement with automatic temperature
compensation
To make the measurement with automatic temperature
compensation one should:
- connect the temperature sensor;
- place the oxygen sensor and temperature probe in the
measured solution;
- turn the meter on with
button;
- choose the unit according to chapter 9.3;
- when measuring in mg/l enter the pressure and salinity
values (chapters 9.1 and 9.2);
- with
button choose the measuring function;
- check or simulate the flow of the measured solution;
- wait till stabilisation of the result about 1  1.5 min
(depending on sensor) and read the value.
11.2. Measurement with manual temperature
compensation
To make the measurement with manual temperature
compensation one should:
- disconnect the temperature sensor;
- place the oxygen sensor in the measured solution;
- turn the meter on with
button;
- choose the unit according to chapter 9.3;
- when measuring in mg/l enter the pressure and salinity
values (chapters 9.1 and 9.2);
- with a thermometer measure the temperature of solution;
- with
mode;
button choose the temperature measuring
,
buttons enter the temperature of the
measured solution;
- check or simulate the flow of the measured solution;
- with
- with
button choose the measuring function;
- wait till stabilisation of result about and read the value.
CAUTION:
in case of measurements in solutions with
low salinity check according to chapter 9.1, weather the entered
value is 0.00 g/l.
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User’s manual - CO-411 Dissolved Oxygen Meter
Pic. 1.
-6-
- 15 -
5. SWITCHING THE METER ON AND OFF
11. OXYGEN CONCENTRATION MEASUREMENT
The meter is switched on by pressing the
button. The
meter tests the memory and display on which all symbols are
displayed.
Before starting the measurement of oxygen dissolved in the
solution it is necessary to prepare the meter for work (chapter 6)
and calibrate the oxygen sensor (chapter 10). Oxygen
measurement in % and in mg/l requires additionally
Pic. 2.
If the test was successful, after about 1.5 s the meter
switches it self automatically to the measuring mode, in
which it was switched off. Continuous displaying of the test
informs about loosing the electrode characteristic. After
pressing the
button the meter will automatically provide
standard characteristic and will enter the measuring mode. It is
necessary to make the calibration after this.
The meter is switched off by pressing the
button.
In case of working on the batteries to save them the meter
switches it self automatically off after 10 minutes from the
last pressing of any button. This function is switched off for
the time of calibration or working with the power adapter.
.
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User’s manual - CO-411 Dissolved Oxygen Meter
temperature measurement to take it’s influence on the
sensor’s membrane into consideration. The measurement in
mg/l, used more frequently, requires additionally
determining the salinity and air pressure. The calculations
are made by the meter with the temperature measured by the
temperature sensor taken into consideration, when automatic
temperature compensation used, or with the temperature set by
the user when manual temperature compensation is used.
Because of limited accuracy of this type of compensation, the
highest accuracy may be achieved by calibrating the oxygen
sensor in this same temperature in which the measurement will
be done. The measurement error is increasing when the
difference between the calibration and measurement
temperatures is growing it is connected with the
characteristic of the sensor and not of the probe. For the
used sensor the error is ±4% when the temperature difference
is 5oC and grows to ±6% when the difference is 10 oC. In
case accurate measurements it is necessary to take into
consideration the time from the last calibration (signal drift).
When the atmospheric pressure is close to 1013 hPa and small
salinity of the measured solution it is not necessary to introduce
this values (standard values should be introduced 0.00 g/l and
1013 hPa). Accurate measurements should be preceded by
determining the salinity of the measured solution. The
easiest way is to calculate the conductivity to salinity in NaCl.
The value of salinity is introduced according to chapter 9.1. It is
also necessary to introduce the actual value of the atmospheric
pressure – chapter 9.2.
- 14 -
-7-
To calibrate the meter one should:
- place the activated sensor in the vessel with 0% saturation
solution;
- choose the saturation in % measurement according to
chapter 9.3;
6. PREPARATION TO WORK
- after the stabilisation of result press and hold the
button till appearing on the display a
symbol what
informs about storing the calibration value, after this on the
display corrected value of the measurement will be
displayed (0%);
Take the sensor out, wash it accurately in distilled water
and put it into 100% oxygen saturated solution ensuring the
liquid flow or leave it on the air.
- after the stabilisation of the result press and hold the
button till appearing on the display a
symbol what
informs about storing the calibration value, after this on
the display corrected value of the measurement will be
displayed (100%);.
If after pressing the
button the meter can’t detect the value
of the sample solution (0% or 100%), instead of the
symbol for a short while an
symbol will be displayed. The
parameters of previous calibration won’t be changed. In this
situation it is necessary to check the condition of the
membrane and the used sample solutions.
10.1. Bringing back the manufacturers characteristic of
the oxygen sensor
Before starting a 1 point calibration of the oxygen sensor it is
necessary to delete the old characteristic. To do so it is
necessary switch off the meter, than press and hold the
and simultaneously switch the meter on. On the display a
sign will be displayed, what informs about deleting the
user’s calibration data and bringing back the factory
characteristic.
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User’s manual - CO-411 Dissolved Oxygen Meter
Before starting the work one should :
- join the power adapter plug to the right input (P) if work
with the power adapter is planned;
- to BNC-50 input (F) join the ready to work oxygen sensor;
- in case of using the temperature probe should be
connected with the chinch temperature input (t);
-
Turn the meter on by pressing the
switch the meter on by pressing the
button.
button.
6.1. Choosing the kind of temperature compensation
The meter switches it self to the automatic temperature
calibration mode automatically after joining the temperature
probe. The measurement will be compensated to the
temperature measured by the sensor.
In case of measurements without the temperature probe,
after disconnecting it the meter enters the manual
temperature compensation mode. By the oxygen
measurement result a blinking symbol will appear and for
the compensation the value set by the user will be taken.
Way of entering the temperature is described below
6.1.1. Entering the temperature
compensation
value
for
manual
To enter the temperature value for the manual temperature
compensation one should:
- disconnect the temperature probe;
- with
button chose the temperature measurement function,
the earlier set value will be displayed and beside it a blinking
symbol;
- with
,
buttons change it for the required value;
- return to the oxygen measuring mode by pressing the
button;
-87. BASIC INFORMATION ABOUT DISSOLVED OXYGEN
MEASUREMENT
The measurement of dissolved oxygen in water solutions is
performed using an oxygen sensor. The basic element of the
sensor is a semi-permeable membrane, which enables the
penetration of oxygen contained in the measured solution, into
the electrolyte – inside of the sensor. The sensor creates a
power source, which voltage depends on the oxygen content in
the electrolyte.
The meter enables measurement in % of oxygen saturation and
mg/l. The calculation of the mg/l value is based on the
saturation measurement in % and the temperature
measurement. When requiring high accuracy during mg/l
measurements, the values of salinity and atmospheric pressure
must be additionally introduced because they have a great
influence on the result. The saturation measurement in % does
not depend on these factors.
The quality of the oxygen sensor has a decisive effect on
the measurement accuracy. The troubles arising during the
measurements are caused mainly (98%) by the sensor, yet
not by the device. In many cases the troubles result from
lack of basic maintenance of the sensor from the user’s
side. It must be remembered, that during the measurement the
sensor takes oxygen from the environment of the membrane.
The sensor’s manufacturers recommend in their
instructions the minimal flow-rate of the tested water,
assuring a stable result. If that requirement is not complied
the result will regularly decrease. During measurements in
stagnant solutions the flow can be partly simulated by keeping
the sensor in motion with a suitable speed. In laboratory
conditions, i.e. performing the measurements in a vessel, the
flow can be forced with a magnetic stirrer. Although it must be
kept in mind that when measuring low O2 saturation intensive
stirring can cause an increase of oxygen content in the tested
solution. Taking water samples and transferring them to the
laboratory can alter the O2 concentration in the samples. The
best results can be achieved only in conditions, which are
recommended by the manufacturer of the sensor in the
operation manual. Long-lasting storing of the sensor without
performing of measurements (above 1 month) requires
removing of the electrolyte. After this period the container must
be filled with a fresh electrolyte and the sensor stored in distilled
water for about 24 hours.
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User’s manual - CO-411 Dissolved Oxygen Meter
- 13 10. CALIBRATION OF THE OXYGEN PROBE
In order to eliminate the measurement error arising from the
individual characteristic of the sensor a calibration of the device
should be carried out. This procedure should be performed
always before operation with a new sensor, after replacing the
membrane or for special requirements concerning the
measurement accuracy. The probes have a so-called “signal
drift” associated with the interval between the calibration and
measurement. A longer interval decreases the measurement
accuracy. The calibration is also recommended if the
temperature of the tested solution differs greatly from the
temperature in which the probe was calibrated, because then an
additional error arises. In this case calibration solutions
should be used, which temperature is almost the same as
the predicted temperature of the tested solutions.
If it is impossible to calibrate the device, the membrane of the
sensor must be replaced according to the manufacturer’s
instruction. This situation usually takes place if the membrane is
strongly polluted or ruptured (sometimes almost invisible). After
replacing the membrane the sensor should be conditioned in
water for 24 hours.
The used oxygen sensors require one or two point calibration in
standard solutions. During two point calibration a solution with
0% oxygen saturation is used (solution of Na2SO3) and second
with 100% oxygen saturation. It can be prepared by aeration of
water for more than ten minutes. When using this solution it
should flow or be stirred. The method of preparing both
solutions is described in detail in the users manual for the
oxygen sensor. A simplified calibration for 100% O2 saturation
can be carried out in the air, without immersing the sensor in
water. Before that the membrane must be wetted with water
for several minutes.
It is assumed that the O2 content in the air correspondents to
100%- saturation, what enables a simplified calibration to be
carried out.
The one point calibration is done only in the solution with 100%
oxygen saturation.
- 12 9.2.
Atmospheric pressure compensation
The value of oxygen saturated in water determined in
mg/l depends directly on the atmospheric pressure
value, this means that 10% pressure change causes oxygen
saturation change for 10%. If the air pressure value is
different than 1013 hPa, this change should be taken into
consideration during the measurements. The CO-411 meter
enables entering the pressure values and calculates the
oxygen saturation changes.
9.2.1. Entering the air pressure value
To enter the air pressure value one should:
- Measure the atmospheric pressure value in hPa;
- in the temperature measuring mode simultaneously press
the
,
buttons for a short while
(pressure)
symbol will be displayed, and next the previously entered
pressure value;
- with
,
buttons enter the measured pressure
value;
- enter the oxygen measurement mode by pressing the
button.
Measurement in % of saturation doesn’t require entering
the pressure value.
9.3. Changing the unit
The measurement result may be displayed in % of the
oxygen saturation or in mg/l. To choose the unit in the
oxygen or temperature measuring mode one should
simultaneously press the
and
, buttons for a short
moment a
(unit) symbol will be displayed. Each pressing
of those button changes the unit from
% to mg/l or
contrary. The meter automatically returns to the oxygen
measuring mode.
Caution: after choosing the mg/l unit by the result there won’t
be any unit symbol displayed. When measurement in
% of saturation was chosen by the result a % symbol
will be displayed.
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User’s manual - CO-411 Dissolved Oxygen Meter
-9A correct measurement is determined by the good condition
of the membrane. The membrane must be free of any cracks
(appearing of electrolyte-drops or white spots when dry).
Before the measurement the electrode should be activated
by storing in distilled water for about 15 minutes. Strongly
polluted wastewater causes after some time clogging of the
membrane. This is revealed by the impossibility of calibrating
of the device at 100% oxygen content (the calibration range
becomes too narrow). In both cases the membrane should
be replaced according to the manufacturer’s instructions.
When replacing the membrane and replenishing the
electrolyte it is important to pay attention weather there are
no air bubbles in the container beneath of the membrane,
because otherwise the measurements will be false. In that
case the twisting of the sensor should be repeated after
refilling the electrolyte. In order to obtain a stable result there
must be some awaiting time before making the reading.
According to the sensor’s manufacturers that is about 1-1,5
min, depending on the thickness of the membrane. The
accuracy of the measurement is connected with the
temperatures of calibration and measurement. The greater
the difference of these temperatures, the greater the
measurement error. The used sensors require a two-point
calibration in a zero O2 saturated solution and an optional
solution (most often a 100% - saturated one). Clean water
contains about 60 ÷ 80% oxygen. Waste water and chemical
solutions are in general less saturated with oxygen but liquids
with forced aeration are much more saturated. When
performing
accurate
measurements
the
sensor’s
manufacturers recommend carrying out calibration just
before the measurement since after some time the sensor’s
parameters are changing. Even the best oxygen sensors
have so called drift about ±1%/24 h.
- 10 -
- 11 -
8. THE OXYGEN SENSOR
The meter may co-operate with polarisation membrane oxygen
sensor with accuracy of ±2%, if the measurement is done in this
same temperature as the calibration. The accuracy of
measurement decreases together with growing of the difference
between the temperature of calibration and temperature of
measurement. It is <4% when the difference is ±5°C and 6%
when the difference is ±10°C. In case of using another
sensor the device requires its adaptation by the
manufacturer. It must be remembered that the membrane of
the sensor should be replaced if it is mechanically damaged or
if the device cannot be calibrated. The necessary procedures
are given in the instruction of the sensor’s manufacturer.
Before starting the work please read carefully the
information given in chapter 7.
9. ENTERING THE OXYGEN METER PARAMETERS
9.1. Salinity influence compensation
Salinity of the solution decreases the oxygen solubility in
water and requires taking into consideration during
measurements in mg/l. 1 g/l change of salinity changes
the oxygen saturation for about 5%. The meter enables
entering the salinity value in g/l and counts the change of
oxygen saturation in mg/l.
Entering the salinity value
The salinity value may be determined on the basis of known
conductivity of the measured solution. The table 1 gives the
real dependence between the salinity and conductivity
counted in NaCl. To enter the salinity value one should:
- with any conductivity meter measure the conductivity of the
solution
- from the table 1 read the salinity value;
- in the oxygen measuring mode press simultaneously the
,
- with
table 1;
buttons till displaying a
,
(salinity) sign on LCD;
buttons enter the salinity value red from the
- enter the oxygen measuring mode by pressing the
button.
Measurement in % of saturation doesn’t require entering
the salinity value
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User’s manual - CO-411 Dissolved Oxygen Meter
mS/cm
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
Table 1.
g/l
0.49
1.00
1.52
2.08
2.63
3.19
3.74
4.29
4.85
5.40
6.00
6.61
7.21
7.83
8.45
9.07
9.70
10.35
11.01
11.66
12.31
12.96
13.61
14.26
14.91
15.56
16.22
mS/cm
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
g/l
16.87
17.52
18.17
18.82
19.46
20.11
20.76
21.41
22.05
22.70
23.35
23.99
24.64
25.29
25.93
26.58
27.23
27.87
28.52
29.17
29.82
30.46
31.11
31.76
32.40
33.05
33.70
mS/cm
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
g/l
34.34
34.99
35.64
36.28
36.93
37.58
38.23
38.87
39.52
40.17
40.81
41.46
42.11
42.75
43.40
44.05
44.70
45.34
45.99
46.64
47.28
47.93
48.58
49.22
49.87
50.63
Table 1. Determining the salinity in g/l NaCl on
the basis of conductivity in mS/cm (in
temperature 25oC).